Latarjet Procedure: Biomechanical Evaluation of 2 Screw Coracoid Fixation

BACKGROUND

Coracoid nonunion is a relevant complication following the Latarjet procedure and is influenced by multiple factors, including the method of graft fixation.

AIMS

The purpose of this study was to evaluate and characterize the biomechanical properties of various two-screw fixation constructs used for coracoid graft fixation in the Latarjet procedure.

METHODS

Forty model scapulae (Sawbones Inc., Vashon, WA, USA) were used for this study. A 15 percent anterior inferior glenoid bone defect was created. The coracoid was osteotomized at the juncture of the vertical and horizontal aspects, transferred to the anterior-inferior edge of the glenoid, and fixed with either two 3.5 mm fully threaded cannulated cortical screws (FTCS), two 3.5 mm fully threaded solid cortical screws (FTSS), two 3.5 mm partially threaded cannulated screws (PTCS), or two 4.5 mm partially threaded malleolar screws (MS). Biomechanical testing was performed with an Instron materials testing machine (Instron Corp., Norwood, MA) by applying loads to the lateral aspect of the transferred coracoid graft. The constructs were preconditioned with non-destructive cyclical loading (0-20N) to determine construct stiffness. After 100 cycles of dynamic loading, the construct was loaded to failure to determine ultimate failure load, yield displacement, and mode of failure.

RESULTS

All failures were associated with plastic deformation of the screws and coracoid graft fracture. There was a significantly lower initial stiffness for PTCS compared to MS (186±49.3 N/mm vs 280±65.5 N/mm, p=0.01) but no significant differences among the other constructs. There was no difference in ultimate failure load (p=0.18) or yield displacement (p=0.05) among constructs.

CONCLUSION

Two screw coracoid fixation of the coracoid in a simulated classic Latarjet procedure with 3.5 mm fully threaded cortical and cannulated screws is comparable to 4.5 mm malleolar screws in strength, stiffness, and displacement at failure. On the other hand, partially threaded 3.5 mm cannulated screws provide inferior fixation stiffness and could potentially affect clinical outcomes.

Clinical Outcomes and Graft Resorption After Metal-Free Bone Block Suture Tape Cerclage Fixation for Recurrent Anterior Shoulder Instability: A Computed Tomography Analysis

BACKGROUND

Glenoid reconstruction with a bone block for anterior glenoid bone loss (GBL) has shown excellent outcomes. However, fixation techniques that require metal implants are associated with metal-related complications and bone graft resorption.

HYPOTHESIS

Arthroscopic glenoid reconstruction using a tricortical iliac crest bone graft (ICBG) and metal-free suture tape cerclage fixation can safely and effectively restore the glenoid surface area in patients with recurrent anterior shoulder instability and anterior GBL.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Adult patients (≥18 years) of both sexes with recurrent anterior shoulder instability and anterior GBL ≥15% were enrolled. These patients underwent arthroscopic glenoid reconstruction with ICBGs and metal-free suture tape cerclage fixation. The effectiveness and clinical outcomes with this technique were evaluated at 24 months using functional scores. Resorption of the graft articular surface was assessed by computed tomography, with the graft surface divided into 6 square areas aligned in 2 columns. Descriptive analysis was conducted.

RESULTS

A total of 23 consecutive patients met inclusion criteria (22 male, 1 female; mean age, 30.5 ± 7.9 years). The mean preoperative GBL was 19.7% ± 3.4%, and there were 15 allograft and 8 autograft ICBGs. All patients exhibited graft union at 3 months. The median follow-up was 38.5 months (interquartile range, 24-45 months). The Western Ontario Shoulder Instability Index, Rowe, Constant-Murley, and Subjective Shoulder Value scores improved from preoperatively (35.1%, 24.8, 83.1, and 30.9, respectively) to postoperatively (84.7%, 91.1, 96.0, and 90.9, respectively) (P < .001). No differences in clinical scores were observed between the graft types. One surgical wound infection was reported, and 2 patients (8.7% [95% CI, 2.4%-26.8%]) required a reoperation. The mean overall glenoid surface area increased from 80.3% ± 3.5% to 117.0% ± 8.3% immediately after surgery before subsequently reducing to 98.7% ± 6.2% and 95.0% ± 5.7% at 12 and 24 months, respectively (P < .001). The mean graft resorption rate was 18.1% ± 7.9% in the inner column and 80.3% ± 22.4% in the outer column. Additionally, 3 patients treated with an allograft (20.0% [95% CI, 7.1%-45.2%]), including the 2 with clinical failures, exhibited complete graft resorption at the last follow-up.

CONCLUSION

Arthroscopic glenoid reconstruction using an ICBG and metal-free suture tape cerclage fixation was safe and effective, yielding excellent clinical outcomes. Resorption of the graft articular surface predominantly affected the nonloaded areas beyond the best-fit circle perimeter.

Accuracy and Consistency of 3D Magnetic Resonance Imaging Is Comparable to 3D Computed Tomography in Assessing Glenohumeral Instability: A Systematic Review

PURPOSE

The purpose of this study is to compare the accuracy of 3D magnetic resonance imaging (MRI) with that of 3D CT in evaluating glenoid bone loss (GBL).

METHODS

This review aligned with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, the Cochrane Library, Embase, and Web of Science were obtained from data inception to Aug 28, 2023. The search term "glenoid bone loss" was extracted and analyzed via stringent inclusion and exclusion criteria. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) combined with the Quality Assessment of Diagnostic Accuracy Studies-Comparative (QUADAS-C) to assess the heterogeneity of included studies.

RESULTS

A total of 1589 related studies were retrieved, and 10 studies were finally included, of which a total of 143 shoulders were evaluated. The index test in QUADAS-C was low risk in 9 studies. 3D MRI measurements of GBL were primarily best-fit circles (n = 9). In both clinical and cadaveric studies, the mean percentages of GBL measured by 3D MRI were 0.38% to 2.19% and 0.25% to 6.1% when compared with 3D CT and standard reference values, respectively. ICC agreement greater than 0.9 between GBL percentages measured by 3D CT and 3D MRI. 3D MRI can also accurately measure glenoid width, glenoid height, humeral head width and height, etc. 3D MRI reconstruction time was similar to that of 3D CT, which was mainly 10-15 min.

CONCLUSIONS

In both clinical and cadaveric studies, compared to 3D CT, 3D MRI is accurate and consistent in assessing glenohumeral bone, especially in measuring GBL, and the reconstruction time of 3D MRI is similar to 3D CT.

conjoint tendon transfer in a 10% anterior glenoid bone loss shoulder instability model

BACKGROUND

The treatment of shoulder instability in patients with subcritical glenoid bone loss poses a difficult problem for surgeons as new evidence supports a higher failure rate when a standard arthroscopic Bankart repair is used. The purpose of this study was to compare a conjoint tendon transfer (soft-tissue Bristow) to an open Bankart repair in a cadaveric instability model of 10% glenoid bone loss.

METHODS

Eight cadaveric shoulders were tested using a custom testing system that allows for a 6-degree-of-freedom positioning of the glenohumeral joint. The rotator cuff muscles were loaded to simulate physiologic muscle conditions. Four conditions were tested: (1) intact, (2) Bankart lesion with 10% bone loss, (3) conjoint tendon transfer, and (4) open Bankart repair. Range of motion, glenohumeral kinematics, and anterior-inferior translation at 60° of external rotation with 20 N, 30 N, and 40 N were measured in the scapular and coronal planes. Glenohumeral joint translational stiffness was calculated as the linear fit of the translational force-displacement curve. Force to anterior-inferior dislocation was also measured in the coronal plane. Repeated measures analysis of variance with a Bonferroni correction was used for statistical analysis.

RESULTS

A Bankart lesion with 10% bone loss increased the range of motion in both the scapular (P = .001) and coronal planes (P = .001). The conjoint tendon transfer had a minimal effect on the range of motion (vs. intact P = .019, .002), but the Bankart repair decreased the range of motion to intact (P = .9, .4). There was a significant decrease in glenohumeral joint translational stiffness for the Bankart lesion compared with intact in the coronal plane (P = .021). The conjoint tendon transfer significantly increased stiffness in the scapular plane (P = .034), and the Bankart repair increased stiffness in the coronal plane (P = .037) compared with the Bankart lesion. The conjoint tendon transfer shifted the humeral head posteriorly at 60° and 90° of external rotation in the scapular plane. The Bankart repair shifted the head posteriorly in maximum external rotation in the coronal plane. There was no significant difference in force to dislocation between the Bankart repair (75.8 ± 6.6 N) and the conjoint tendon transfer (66.5 ± 4.4 N) (P = .151).

CONCLUSION

In the setting of subcritical bone loss, both the open Bankart repair and conjoint tendon transfer are biomechanically viable options for the treatment of anterior shoulder instability; further studies are needed to extrapolate these data to the clinical setting.

Posterior Shoulder Instability and Glenoid Bone Loss: A Review and a Free Bone Graft Technique

Posterior glenoid bone loss (pGBL) is frequently associated with posterior shoulder instability. Posterior glenohumeral instability accounts for a small percentage of shoulder pathologies, and critical bone loss in posterior instability has not been well defined in the literature. Younger patient populations who participate in activities that repetitively stress the posterior stabilizing structures of the shoulder are more prone to developing posterior shoulder instability. A variety of surgical options have been described, ranging from isolated capsulolabral repair to glenoid osteotomy. Soft-tissue repair alone may be an inadequate treatment in cases of pGBL and places patients at a high risk of recurrence. Our preferred technique for posterior glenoid reconstruction in cases of pGBL involves the transfer of a free iliac crest bone graft onto the native glenoid. The graft is contoured to fit the osseous defect and secured to provide an extension of the glenoid track. In this study, we review pGBL in the setting of posterior instability and describe our technique in detail. Further long-term studies are needed to refine the indications for glenoid bone graft procedures and quantify what constitutes a critical pGBL.

Distal Tibial Allograft for the Treatment of Anterior Shoulder Instability With Glenoid Bone Loss: A Systematic Review and Meta-analysis

BACKGROUND

The use of a distal tibial allograft (DTA) for reconstruction of a glenoid defect in anterior shoulder instability has grown significantly over the past decade. However, few large-scale clinical studies have investigated the clinical and radiographic outcomes of the DTA procedure.

PURPOSE

To conduct a systematic review and meta-analysis of clinical studies with data on outcomes and complications in patients who underwent the DTA procedure for recurrent anterior shoulder instability with glenoid bone loss.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

A comprehensive search of major bibliographic databases was conducted for articles pertaining to the use of a DTA for the management of anterior shoulder instability with associated glenoid bone loss. Postoperative complications and outcomes were extracted and compiled in a meta-analysis.

RESULTS

Of the 8 included studies with 329 total participants, the mean patient age was 28.1 ± 10.8 years, 192 (83.8%) patients were male, and the mean follow-up was 38.4 ± 20.5 months. The overall complication rate was 7.1%, with hardware complications (3.8%) being the most common. Partial graft resorption was observed in 36.5% of the participants. Recurrent subluxation was reported in 1.2% of the participants, and recurrent dislocation prompting a reoperation was noted in 0.3% of the participants. There were significant improvements in clinical outcomes, including American Shoulder and Elbow Surgeons score (40.9-point increase; P < .01), Single Assessment Numeric Evaluation (47.2-point increase; P < .01), Western Ontario Shoulder Instability Index (49.4-point decrease; P < .01), Disabilities of the Arm, Shoulder and Hand (20.0-point decrease; P = .03), and visual analog scale (2.1-point decrease; P = .05). Additionally, postoperative shoulder range of motion significantly increased from baseline values.

CONCLUSION

The DTA procedure was associated with a low complication rate, good clinical outcomes, and improved range of motion among patients with anterior shoulder instability and associated glenoid defects.

Reliability of Manual Measurements Versus Semiautomated Software for Glenoid Bone Loss Quantification in Patients With Anterior Shoulder Instability

Background

The presence of glenoid bone defects is indicative in the choice of treatment for patients with anterior shoulder instability. In contrast to traditional linear- and area-based measurements, techniques such as the consideration of glenoid concavity have been proposed and validated.

Purpose

To compare the reliability of linear (1-dimensional [1D]), area (2-dimensional [2D]), and concavity (3-dimensional [3D]) measurements to quantify glenoid bone loss performed manually and to analyze how automated measurements affect reliability.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

Computed tomography images of 100 patients treated for anterior shoulder instability with differently sized glenoid defects were evaluated independently by 2 orthopaedic surgeons manually using conventional software (OsiriX; Pixmeo) as well as automatically with a dedicated prototype software program (ImFusion Suite; ImFusion). Parameters obtained included 1D (defect diameter, best-fit circle diameter), 2D (defect area, best-fit circle area), and 3D (bony shoulder stability ratio) measurements. Mean values and reliability as expressed by the intraclass correlation coefficient [ICC]) were compared between the manual and automated measurements.

Results

When manually obtained, the measurements showed almost perfect agreement for 1D parameters (ICC = 0.83), substantial agreement for 2D parameters (ICC = 0.79), and moderate agreement for the 3D parameter (ICC = 0.48). When measurements were aided by automated software, the agreement between raters was almost perfect for all parameters (ICC = 0.90 for 1D, 2D, and 3D). There was a significant difference in mean values between manually versus automatically obtained measurements for 1D, 2D, and 3D parameters (P < .001 for all).

Conclusion

While more advanced measurement techniques that take glenoid concavity into account are more accurate in determining the biomechanical relevance of glenoid bone loss, our study showed that the reliability of manually performed, more complex measurements was moderate.

Yoke procedure as a salvage treatment option for failed reverse total shoulder arthroplasty with irreconstructible glenoid

BACKGROUND

Glenoid bone loss is a known challenge in primary and revision reverse total shoulder arthroplasty. In severe deficiency, even placing the baseplate in alternative centerline or using an augmented baseplate may be insufficient. This study reports on the use of a soft tissue resurfacing technique using Achilles tendon allograft, coined Yoke procedure, for salvage treatment of glenoid deficient shoulder requiring reconstruction.

MATERIALS AND METHODS

All patients who underwent the Yoke procedure between 2014 and 2020 by a single surgeon at a single academic center were identified and had their charts retrospectively reviewed. Demographics and surgical information were recorded. Preoperative X-rays and 3D-computed tomography scans were reviewed to classify patient glenoid types, evaluate glenoid medialization, and measure shoulder angles. Preoperative and postoperative range of motions and patient-reported outcome scores were evaluated, including anterior elevation, external rotation, internal rotation, visual analog scale, subjective shoulder value score, Simple Shoulder Test, and American Shoulder and Elbow Surgeons (ASES) scores. Postoperative radiographs and follow-up notes were reviewed to evaluate postoperative complication profiles at 1 year.

RESULTS

Seven patients with a median age of 69 years (range, 54-77 years) underwent Yoke procedure and had a median 12-month follow-up (range, 9-56 months). All patients were female and had a median of 2 prior shoulder surgeries (range, 0-13). Of all the patients, the most common comorbidity was osteoporosis (6) followed by rheumatoid arthritis (3). Of the 5 patients who had previous arthroplasty, the most common indications were baseplate failure (4), followed by instability (3) and infection (3). The median visual analog scale score improved from 8 (range, 3-9) to 2 (range, 1-4). The median Simple Shoulder Test improved from 8% (range, 0%-42%) to 33% (range, 17%-83%). The median ASES score improved from 15 (range, 5-38) to 52 (range, 40-78). The median anterior elevation and external rotation improved from 20° (range, 0°-75°) to 100° (range, 40°-145°) and 10° (range, 0°-20°) to 20° (range, 0°-55°), respectively. There was no change in median internal rotation. As of the last follow-up, one patient reported postoperative complications of anterior-superior implant escape, heterotopic ossification, and scapular notching.

CONCLUSION

The Yoke procedure is a promising salvage treatment that can offer patients consistent pain reduction and moderate functional improvements at short-term follow-up. In the setting of poor bone quality and severe glenoid deficiency, glenoid baseplate implantation may not be absolutely necessary for a pain-relieving, functionally acceptable outcome.

Femoral head allograft for glenoid bone loss in primary reverse shoulder arthroplasty: functional and radiologic outcomes

BACKGROUND

Several techniques have been adopted during primary reverse shoulder arthroplasty (RSA) to manage glenoid bone defect. Among bone grafts, humeral head autograft is currently the mainstream option. However, autologous humeral heads may be unavailable or inadequate, and allografts may be a viable alternative. The aim of the present study was to evaluate the functional and radiologic outcomes of femoral head allografts for glenoid bone defects in primary RSA.

METHODS

We conducted a retrospective study with prospective data collection enrolling 20 consecutive patients who underwent RSA with femoral head allografts for glenoid bone defects. Indications for surgery were eccentric cuff tear arthropathy in 10 cases (50%), concentric osteoarthritis in 9 cases (45%), and fracture sequelae in 1 case (5%). Each patient was evaluated preoperatively and at follow-up by radiologic and computed tomography (CT) and by assessing the range of motion (ROM) and the Constant-Murley score (CMS). A CT-based software, a patient-specific 3D model of the scapula, and patient-specific instrumentation were used to shape the graft and to assess the position of K-wire for the central peg. Postoperatively, CT scans were used to identify graft incorporation and resorption.

RESULTS

After a median follow-up of 26.5 months (24-38), ROM and CMS showed a statistically significant improvement (all P = .001). The median measures of the graft were as follows: 28 mm (28-29) for diameter, 22° (10°-31°) for angle, 4 mm (2-8 mm) for minimum thickness, and 15 mm (11-21 mm) for maximum thickness. Before the surgery, the median glenoid version was 21.8° (16.5°-33.5°) for the retroverted glenoids and -13.5° (-23° to -12°) for the anteverted glenoids. At the follow-up, the median postoperative baseplate retroversion was 5.7° (2.2°-1.5°) (P = .001), and this value was close to the 4° retroversion planned on the preoperative CT-based software. Postoperative major complications were noted in 4 patients: 2 dislocations, 1 baseplate failure following a high-energy trauma, and 1 septic baseplate failure. Partial graft resorption without glenoid component failure was observed in 3 cases that did not require revision surgery.

CONCLUSION

The femoral head allograft for glenoid bone loss in primary RSA restores shoulder function, with CMS values comparable to those of sex- and age-matched healthy individuals. A high rate of incorporation of the graft and satisfactory correction of the glenoid version can be expected after surgery. The management of glenoid bone defects remains a challenging procedure, and a 15% risk of major complication must be considered.

Bipolar bone loss and distance to dislocation

Studies have shown that glenoid- and humeral-sided bone loss may be present in up to 73-93% of individuals with recurrent anterior shoulder instability. As such, bone loss must be addressed appropriately, as the amount of bone loss drives surgical decision making and influences outcomes. Methods to describe and measure bone loss have changed over time. Originally, glenoid and humeral bone loss were viewed separately. However, the concepts of bipolar bone loss, the glenoid track (GT), and "on/off-track" lesions arose, highlighting the interplay between the two entities in contributing to recurrent instability. Classically, "off-track" lesions have been described as those Hill-Sachs interval (HSI) greater than the GT, and have been shown to result in higher rates of re-instability when addressed nonoperatively or with Bankart repair alone. More recently, further attention has been given to "on-track" lesions (HSI < GT). The new concept of "distance to dislocation" (DTD) has gained popularity. DTD is calculated as the difference between the GT and HSI, and literature evaluating DTD suggests that not all "on-track" lesions should be treated in the same manner. The purpose of this concept review article is twofold: (I) describe glenoid, humeral, and bipolar bone loss in the setting of anterior shoulder instability; and (II) elaborate on the new concept of "DTD" and its use in guidance of management.

Comparison of the Glenoid Index by Computed Tomography With Magnetic Resonance Imaging

Introduction Anterior shoulder instability results in labral and osseous glenoid injuries. With a large osseous defect, there is a risk of recurrent dislocation of the joint, and therefore the patient has to undergo surgical correction. An MRI evaluation of the patient helps to assess the soft tissue injury. Currently, the volumetric three-dimensional (3D) reconstructed CT image is the standard for measuring glenoid bone loss and the glenoid index. However, it has the disadvantage of exposing the patient to radiation and additional expenses. This study aims to compare the values of the glenoid index using MRI and CT. Methodology The present study was a two-year cross-sectional study of patients with shoulder pain, trauma, and dislocation in a tertiary hospital in Karnataka. The sagittal proton density (PD) section of the glenoid and enface 3D reconstructed images of the scapula were used to calculate glenoid bone loss and the glenoid index. The baseline data were analyzed using descriptive statistics, and the Chi-square test was used to test the association of various complications with selected variables of interest. Results The glenoid index calculated in the current study using 3D volumetric CT images and MR sagittal PD images was 0.95±0.01 and 0.95±0.01, respectively. The CT and MRI glenoid bone loss was 5.41±0.65% and 5.38±0.65%, respectively. When compared, the glenoid index and bone loss calculated by MRI and CT revealed a high correlation and significance with a p-value of <0.001. Conclusions The study concluded that MRI is a reliable method for glenoid measurement. The sagittal PD sequence combined with an enface glenoid makes it possible to identify osseous defects linked to glenohumeral joint damage and dislocation. The values derived from 3D CT are identical to the glenoid index and bone loss determined using the sagittal PD sequence in MRI.

Distal Radius Allograft for Glenohumeral Instability: A Novel Osteochondral Allograft Reconstruction Option in the Setting of Glenoid Bone Loss

BACKGROUND

Distal tibial allograft (DTA) reconstruction for glenoid bone loss is nonanatomic, as it does not match the glenoid radius of curvature (ROC) in the anterior-posterior (AP) plane. The dorsal articular portion of the distal radius has not been previously described as an allograft reconstruction option for glenoid bone loss.

PURPOSE

To evaluate distal radius fresh-frozen allograft (DRA) as a potential match for glenoid reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen fresh-frozen human cadaveric specimens-including 6 shoulder, 6 wrist, and 6 tibia specimens-were used. The ROC and the graft length were measured in the superior-inferior (SI) plane. A 30% defect was created in all glenoid specimens, and both DTAs and DRAs were harvested to assess graft fit after fixation. Computed tomography analysis was used to assess bony ROC and bone mineral density (BMD).

RESULTS

The cadaveric specimens had a mean age of 77 years. The mean SI glenoid length was 39.7 mm compared with 36.8 mm for the DRA and 30 mm for the DTA. The ROC in the SI plane was 29 ± 5.3 mm for the glenoid, 37.8 ± 4.9 mm for the DRA, and 24 ± 3.7 mm for the DTA. In the AP plane, the ROC was 39.6 ± 6.6 mm for the glenoid, 30.4 ± 18.6 mm for the DRA, and 126.3 ± 9.5 mm for the DTA. On computed tomography analysis, the ROC in the SI plane was 30.4 ± 1.5 mm for the glenoid, 30.3 ± 5.6 mm for the DRA, and 24.5 ± 9.4 mm for the DTA. In the AP plane, the ROC was 30.8 ± 2 mm for the glenoid, 19.1 ± 2.3 mm for the DRA, and 46.7 ± 21.7 mm for the DTA. The BMD was 226.3 ± 79 Hounsfield units (HU) for the glenoid, 228.5 ± 94.7 HU for the DRA, 235 ± 96.2 HU for the coracoid process, and 235.1 ± 84.6 HU for the DTA.

CONCLUSION

Compared with the DTA, the DRA had a greater mean graft length in the SI plane, providing utilization in cases of larger bony defects; the DRA has a more acute ROC in the AP plane (closer to that of the glenoid), providing a greater potential buttress to anterior humeral translation. Compared with currently utilized grafts, the DRA BMD was not significantly diminished. This study presents the DRA as a novel allograft reconstruction option in the setting of anterior glenoid bone loss; further biomechanical and clinical investigation is indicated.

Glenoid segmentation from computed tomography scans based on a 2-stage deep learning model for glenoid bone loss evaluation

BACKGROUND

The best-fitting circle drawn by computed tomography (CT) reconstruction of the en face view of the glenoid bone to measure the bone defect is widely used in clinical application. However, there are still some limitations in practical application, which can prevent the achievement of accurate measurements. This study aimed to accurately and automatically segment the glenoid from CT scans based on a 2-stage deep learning model and to quantitatively measure the glenoid bone defect.

MATERIALS AND METHODS

Patients who were referred to our institution between June 2018 and February 2022 were retrospectively reviewed. The dislocation group consisted of 237 patients with a history of ≥2 unilateral shoulder dislocations within 2 years. The control group consisted of 248 individuals with no history of shoulder dislocation, shoulder developmental deformity, or other disease that may lead to abnormal morphology of the glenoid. All patients underwent CT examination with a 1-mm slice thickness and a 1-mm increment, including complete imaging of the bilateral glenoid. A residual neural network (ResNet) location model and a U-Net bone segmentation model were constructed to develop an automated segmentation model for the glenoid from CT scans. The data set was randomly divided into training (201 of 248) and test (47 of 248) data sets of control-group data and training (190 of 237) and test (47 of 237) data sets of dislocation-group data. The accuracy of the stage 1 (glenoid location) model, the mean intersection-over-union value of the stage 2 (glenoid segmentation) model, and the glenoid volume error were used to assess the performance of the model. The R2 value and Lin concordance correlation coefficient were used to assess the correlation between the prediction and the gold standard.

RESULTS

A total of 73,805 images were obtained after the labeling process, and each image was composed of CT images of the glenoid and its corresponding mask. The average overall accuracy of stage 1 was 99.28%; the average mean intersection-over-union value of stage 2 was 0.96. The average glenoid volume error between the predicted and true values was 9.33%. The R2 values of the predicted and true values of glenoid volume and glenoid bone loss (GBL) were 0.87 and 0.91, respectively. The Lin concordance correlation coefficient value of the predicted and true values of glenoid volume and GBL were 0.93 and 0.95, respectively.

CONCLUSION

The 2-stage model in this study showed a good performance in glenoid bone segmentation from CT scans and could quantitatively measure GBL, providing a data reference for subsequent clinical treatment.

A comprehensive comparison and evaluation of surgical techniques for anterior shoulder instability: a Bayesian network meta-analysis

BACKGROUND

Anterior shoulder instability is a common clinical problem; however, conflicting evidence exists regarding optimal treatment algorithms. We perform a comparative analysis of stabilization techniques used for recurrent anterior shoulder instability to identify the one associated with the lowest rate of recurrent instability. We additionally explore how glenoid bone loss and osseus lesions affect recurrence rates.

METHODS

PubMed, MEDLINE, Embase, and Cochrane databases were searched for clinical studies comparing surgical techniques for anterior shoulder instability. Two team members independently assessed all potential studies for eligibility and extracted data. Each included study underwent a risk of bias assessment using the Cochrane risk of bias summary tool. The primary outcome of interest was the rate of recurrent instability, which underwent a Bayesian network meta-analysis. Additional analyses were performed relating to the degree of glenoid bone loss and the presence of osseous lesions.

RESULTS

Of 2699 studies screened, 52 studies with 4209 patients were included. Patients who underwent open Latarjet demonstrated the overall lowest rate of recurrent instability [log odds ratio (LOR) 1.93], whereas patients who underwent arthroscopic Bankart repair demonstrated the highest (LOR 2.87). When glenoid bone loss was 10% to 20%, open Latarjet had significantly lower recurrent instability (P = .0016) compared to arthroscopic Bankart repair. When glenoid bone loss increased from 0%-10% to 10%-20%, arthroscopic Bankart repair had a significantly increased rate of recurrence (P = .021). In the presence of an engaging Hill-Sachs lesion, both open Latarjet (P = .01) and arthroscopic Bankart with remplissage (P = .029) had significantly reduced recurrence rates compared to arthroscopic Bankart repair. Finally, regardless of procedure, the presence of a Hill-Sachs or bony Bankart lesion was associated with an increased risk of recurrent instability (r = 0.44, P = .0003, and r = 0.40, P = .006, respectively).

CONCLUSION

The open Latarjet has the overall lowest recurrent instability and significantly lower compared to arthroscopic Bankart repair in the setting of increasing glenoid bone loss. Bone loss between 0% and 10% results in similar outcomes across all procedures.

Strategies for the planning of complex shoulder arthroplasty: Use of a custom-made glenoid component in reverse shoulder arthroplasty for a neglected posterior fracture dislocation of the shoulder with malunited scapula fractures and severe eccentric glenoid bone loss

Glenoid bone loss associated with abnormal glenoid morphology can be encountered in complex primary and revision reverse shoulder arthroplasty. Strategies to deal with this include allografts, augments and custom-made prostheses. We describe a unique case of a long-standing neglected posterior fracture dislocation of the shoulder with severe glenoid bone loss and retroversion. The patient also had malunited acromial and scapula fractures and an associated rotator cuff tear. The primary challenges were access to the shoulder joint due to the malunited fractures, reconstruction of the dysplastic glenoid and providing joint stability. A reverse shoulder replacement was planned using a custom-made glenoid component and patient-specific instrumentation (PSI). The custom base plate was manufactured based on the pre-operative computerised tomography (CT) scan and conformed to the native glenoid. A post-operative CT scan confirmed adequate positioning of the implants. 30 months following surgery, there was a significant improvement in pain and range of motion with an Oxford Shoulder Score (OSS) of 39/48, compared to a pre-operative score of 12/48. Plain radiographs did not show any evidence of loosening or osteolysis. This case report highlights the approach for planning a complex reverse shoulder arthroplasty and the use of custom-made prostheses and PSI in such scenarios.

Cadaveric Biomechanical Study of Partial Glenoid Arthroplasty Versus the Latarjet Procedure for Anterior Glenoid Bone Loss

BACKGROUND

For severe anterior glenoid bone loss due to recurrent shoulder instability, the Latarjet procedure offers a dynamic sling effect in addition to bone augmentation. Yet, it heavily alters the surrounding anatomy, while fixation and graft union issues are also common.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare a novel printed 3-dimensional (3D) partial glenoid arthroplasty (PGA) implant with the classic Latarjet procedure. It was hypothesized that by replicating the original glenoid geometry and preserving soft tissue anatomy, PGA may better reproduce normal joint kinematics. In addition, the locking screw construct may offer stronger fixation.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 14 matched cadaveric shoulders were tested. The PGA implant was 3D printed in titanium based on preoperative computed tomography. The intact, 25% anterior glenoid bone loss, and postoperative states were tested in the scapular and coronal planes. The following parameters were measured: articular surface area and stepoff, rotational range of motion and the humeral head apex position during rotation, and load and linear stiffness at 25% anterior translation and at 2-mm construct displacement.

RESULTS

The baseline dimensions of the glenoid articular surface were comparable between the groups. The articular surface area after PGA was significantly larger (P = .006) with less articular stepoff (P = .030). PGA better approximated the intact state's external (P = .006) and total (P = .019) rotational range of motion in the scapular plane. The course of the humeral head apex after PGA better followed that of the intact state (P < .001). Resistance against anterior translation after PGA was not significantly different compared with after the Latarjet procedure. Greater linear stiffness (P = .031) and loading (P = .002) at 2-mm construct displacement were demonstrated in the PGA group.

CONCLUSION

In addressing anterior glenoid bone loss, PGA better approximated intact glenohumeral joint kinematics compared with the Latarjet procedure with less articular stepoff in a cadaveric model. PGA was comparable in resisting anterior translation while being significantly stronger against loading at 2-mm construct displacement. Further clinical studies are warranted to validate this novel procedure.

CLINICAL RELEVANCE

A 3D-printed PGA implant may offer an alternative treatment option for severe glenoid bone loss due to shoulder instability, overcoming the previous drawbacks of the Latarjet procedure, including altered kinematics, fixation failure, and hardware issues.

Risk Factors for Glenoid Bone Loss in the Setting of Posterior Glenohumeral Instability

Background

Posterior instability has been reported to account for up to 24% of cases of shoulder instability in certain active populations. However, there is a paucity of data available regarding the risk factors associated with posterior glenoid bone loss.

Purpose

To characterize the epidemiology of, and risk factors associated with, glenoid bone loss within a cohort of patients who underwent primary arthroscopic shoulder stabilization for isolated posterior-type glenohumeral instability.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

This was a retrospective analysis of patients who underwent primary arthroscopic shoulder stabilization for posterior-type instability between January 2011 and December 2019. Preoperative magnetic resonance arthrograms were used to calculate posterior glenoid bone loss using a perfect circle technique. Patient characteristics and revision rates were obtained. Bone loss (both in millimeters and as a percentage) was compared between patients based on sex, age, arm dominance, sports participation, time to surgery, glenoid version, history of trauma, and number of anchors used for labral repair.

Results

Included were 112 patients with a mean age of 28.66 ± 10.07 years; 91 patients (81.25%) were found to have measurable bone loss. The mean bone loss was 2.46 ± 1.68 mm (8.98% ± 6.12%). Significantly greater bone loss was found in athletes versus nonathletes (10.09% ± 6.86 vs 7.44% ± 4.56; P = .0232), female versus male patients (11.17% ± 6.53 vs 8.17% ± 5.80; P = .0212), and patients dominant arm involvement versus nondominant arm involvement (10.26% ± 5.63 vs 7.07% ± 6.38; P = .0064). Multivariate regression analysis identified dominant arm involvement as an independent risk factor for bone loss (P = .0033), and dominant arm involvement (P = .0024) and athlete status (P = .0133) as risk factors for bone loss >13.5%. At the conclusion of the study period, 7 patients had experienced recurrent instability (6.25%).

Conclusion

The findings of this study are in alignment with existing data suggesting that posterior glenoid bone loss is highly prevalent in patients undergoing primary arthroscopic stabilization for posterior-type shoulder instability. Our results suggest that patients with dominant arm involvement are at risk for greater posterior glenoid bone loss. Athlete status and dominant arm involvement were identified as independent risk factors for bone loss >13.5%.

Primary Stability and Bone Contact Loading Evaluation of Suture and Screw based Coracoid Graft Fixation for Anterior Glenoid Bone Loss

BACKGROUND

Reconstruction techniques for anterior glenoid bone loss have seen a trend from screws to suture-based fixations. However, comparative biomechanical data, including primary fixation and glenoid-graft contact pressure mapping, are limited.

HYPOTHESIS

Suture-based bone block cerclage (BBC) and suspensory suture button (SB) techniques provide similar primary fixation and cyclic stability to double-screw fixation but with higher contact loading at the bony interface.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 60 cadaveric scapulae were prepared to simulate anterior glenoid bone loss with coracoid autograft reconstruction. Graft fixation was performed with 3 different techniques: (1) an interconnected all-suture BBC, (2) 2 SB suspensions, and (3) 2 screws. Initial compression was analyzed during primary fixation. Cyclic peak loading with 50 N and 100 N over 250 cycles at 1 Hz was performed with a constant valley load of 25 N. Optical recording and pressure foils allowed for spatial bone block tracking and contact pressure mapping at the glenoid-graft interface. Load-to-failure testing was performed at a rate of 1.5 mm/s with ultimate load and stiffness measured.

RESULTS

Initial graft compression was higher with screw fixation (141 ± 5 N) compared with suture-based fixations (P < .001), with BBC fixation providing significantly higher compression than SB fixation (116 ± 7 N vs. 91 ± 5 N; P < .001). Spatial bone block migration and ultimate failure load were similar between the BBC and screw groups. The SB group showed significantly increased bone block translation (3.1 ± 1.0 mm; P≤ .014) and rotation (2.5°± 1.4°; P≤ .025) and significantly lower ultimate failure load (180 ± 53 N) compared with the BBC (P = .046) and screw (P = .002) groups. Both suture-based fixations provided significantly increased graft-glenoid contact loading with higher pressure amplitudes (P≤ .032) and contact pressure after cyclic loading (+13%; SB: P = .007; BBC: P = .004) compared with screw fixation.

CONCLUSION

Both SB and interconnected cerclage fixation improved dynamic contact loading compared with screw fixation in a biomechanical glenoid bone loss model. Cerclage fixation was biomechanically comparable with screw fixation but with a greater variability. SB fixation showed significantly lower primary fixation strength and greater bone block rotation and migration.

CLINICAL RELEVANCE

Suture-based bone block fixations improved graft-glenoid contact loading, but the overall clinical consequence on healing remains unclear.

Acromion morphology is associated with glenoid bone loss in posterior glenohumeral instability

BACKGROUND

The acromion morphology in a shoulder with posterior instability differs from that of a shoulder without glenohumeral instability. Specifically, the acromion with a flatter sagittal tilt, greater posterior acromial height, and less posterior coverage is associated with posterior instability. However, the association between acromion morphology and glenoid bone loss (GBL) in the setting of posterior glenohumeral instability has not previously been investigated. The purpose of this study was to determine whether acromial morphology influences the extent or pattern of posterior GBL in a cohort of patients with posterior glenohumeral instability.

METHODS

This multicenter retrospective study identified 89 shoulders with unidirectional posterior glenohumeral instability. Total area GBL was measured using the best-fit circle method on magnetic resonance imaging (MRI). Shoulders were divided into 3 groups: (1) no GBL (n = 30), (2) GBL 0%-13.5% (n = 45), or (3) GBL ≥13.5% (n = 14). Acromion measurements were performed on MRI and included acromial tilt, posterior acromial height, anterior acromial coverage, and posterior acromial coverage.

RESULTS

Patients without GBL had a steeper acromial tilt (58.5° ± 1.4°) compared with those with 0%-13.5% GBL (64.3° ± 1.5°) or GBL ≥13.5% (67.7° ± 1.8°) (P = .004). Patients without GBL also had greater posterior coverage (65.4° ± 1.7°) compared with those with GBL (60.3° ± 1.4°) (P = .015). Posterior acromion height was not significantly different among groups.

CONCLUSION

The results demonstrate that an acromion with a flatter sagittal tilt and less posterior coverage is associated with GBL in the setting of posterior glenohumeral instability. This is important to consider as posterior GBL has been identified as a risk factor for failure of posterior soft tissue-stabilizing procedures.

Remodeling process and clinical outcomes following all-arthroscopic modified Eden-Hybinette procedure using iliac crest autograft and 1-tunnel double Endobutton fixation system

BACKGROUND

Arthroscopically modified Eden-Hybinette procedures for glenohumeral stabilization have been used for a long time. With the advancement of arthroscopic techniques and the development of sophisticated instruments, a double Endobutton fixation system has been used clinically to secure bone graft to the glenoid rim placed through a specifically designed guide. The purpose of this report was to evaluate clinical outcomes and serial glenoid remodeling process following all-arthroscopic anatomical glenoid reconstruction using autologous iliac crest bone grafting technique through 1-tunnel fixation.

METHODS

Forty-six patients with recurrent anterior dislocations and significant glenoid defects greater than 20% underwent arthroscopic surgery with a modified Eden-Hybinette technique. Instead of firm fixation, autologous iliac bone graft was fixed to the glenoid by double Endobutton fixation system through 1-tunnel placed in the glenoid surface. Follow-up examinations were performed at 3, 6, 12, and 24 months. The patients were followed up for a minimum of two years using the Rowe score, the Constant score, the Subjective Shoulder Value, and the Walch-Duplay score; patient satisfaction with the procedure outcome was also rated. Graft positions, healing, and absorption were evaluated postoperatively with computed tomography imaging.

RESULTS

At a mean follow-up of 28 months, all patients were satisfied and had a stable shoulder. The Constant score improved from 82.9 to 88.9 points (P ＜ .001), the Rowe score, improved from 25.3 to 89.1 points (P < .001), the Subjective Shoulder Value improved from 31% to 87% (P < .001), and the Walch-Duplay score improved from 52.5 to 85.7 points (P ＜ .001). One donor-site fracture occurred during the follow-up period. All grafts were well-positioned and achieved optimal bone healing with zero excessive absorption. The preoperative glenoid surface (72.6% ± 4.5%) increased significantly immediately after surgery to 116.5% ± 9.6% (P ＜ .001). After a physiological remodeling process, the glenoid surface remained significantly increased at the last follow-up (99.2% ± 7.1%) (P ＜ .001). The glenoid surface area appeared to decrease serially when compared between the first 6 months and 12 months postoperatively, while there was no significant interval change between 12 and 24 months postoperatively.

CONCLUSION

Patient outcomes were satisfactory following the all-arthroscopic modified Eden-Hybinette procedure using an autologous iliac crest grafting technique through one-tunnel fixation system with double Endobutton. Graft absorption mostly occurred on the edge and outside the ''best-fit'' circle of the glenoid. Glenoid remodeling occurred within the first year after all-arthroscopic glenoid reconstruction with an auto iliac bone graft.

Bone loss in shoulder instability: putting it all together

Glenohumeral bone loss is frequently observed in cases of recurrent anterior and posterior shoulder instability and represents a risk factor for failure of nonoperative treatment. Patients with suspected glenoid or humeral bone loss in the setting of recurrent instability should be evaluated with a thorough history and physical examination, as well as advanced imaging including computed tomography (CT) and/or magnetic resonance imaging (MRI). In cases of both anterior and posterior instability, the magnitude and location of bone loss should be determined, as well as the relationship between the glenoid track (GT) and any humeral defects. While the degree and pattern of osseous deficiency help guide treatment, patient-specific risk factors for recurrent instability must also be considered when determining patient management. Treatment options for subcritical anterior bone loss include labral repair and capsular plication, while more severe deficiency should prompt consideration of bony augmentation including coracoid transfer or free bone block procedures. Concomitant humeral lesions are treated according to the degree of engagement with the glenoid rim and may be addressed with soft tissue remplissage or bony augmentation procedures. While critical and subcritical thresholds of glenoid bone loss guide the management of anterior instability, such thresholds are less defined in the setting of posterior instability. Furthermore, current treatment algorithms are limited by a lack of long-term comparative studies. Future high-quality studies as well as possible modifications in indications and surgical technique are required to elucidate the optimal treatment of anterior, posterior, and bipolar glenohumeral bone loss in the setting of recurrent shoulder instability.

Prevalence and Risk Factors of Glenoid Bone Loss in Combined Shoulder Instability in Young, Active-Duty Military Patients

Background

US military servicemembers experience higher rates of posterior and combined-type instability as compared with their nonmilitary peers.

Purpose

(1) To determine the prevalence of glenoid bone loss (GBL) in young, active-duty military patients with combined-type shoulder instability who underwent operative shoulder stabilization; (2) to evaluate whether GBL is associated with differences in postoperative outcomes; and (3) to identify factors associated with larger defects.

Study Design

Case series; Level of evidence, 4.

Methods

This study included active-duty military patients who underwent primary surgical shoulder stabilization for combined anterior and posterior capsulolabral tears between January 2012 and December 2018. Preoperative magnetic resonance arthrograms were used to calculate anterior, posterior, and total GBL using the "perfect circle" technique. We recorded patient characteristics, revisions, complications, return to duty, range of motion, and scores on multiple outcome measures (visual analog scale for pain, Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons, and Rowe). GBL prevalence was compared by time to surgery, glenoid version, history of trauma, and number of anchors used for labral repair. Outcome scores, return to active duty, and revision procedures were compared by degree of anterior or posterior GBL: <13.5% (mild) versus ≥13.5% (subcritical).

Results

GBL was noted in 28 (77.8%) of the 36 patients. Nineteen (52.8%) patients had anterior GBL, 18 (50.0%) had posterior, and 9 (25.0%) had combined. Four (11.1%) patients had subcritical anterior or posterior GBL. Increased posterior GBL was associated with history of trauma (P = .041), time to surgery >12 months (P = .024), and glenoid retroversion ≥9° (P = .010); increased total GBL was associated with longer time to surgery (P = .023) and labral repair requiring >4 anchors (P = .012); and increased anterior GBL was associated with labral repair requiring >4 anchors (P = .011). There were statistically significant improvements on all outcome measures, with no changes in range of motion postoperatively. No significant difference on any outcome score was observed between patients with mild and subcritical GBL.

Conclusion

In our analysis, 78% of patients had appreciable GBL, suggesting that GBL is highly prevalent in this patient population. Longer time to surgery, traumatic cause, significant glenoid retroversion, and large labral tears were identified as risk factors for increased GBL.

Complete Restoration of Native Glenoid Width Improves Glenohumeral Biomechanics After Simulated Latarjet

BACKGROUND

The amount of glenoid width that must be restored with a Latarjet procedure in order to reestablish glenohumeral stability has not been determined.

PURPOSE/HYPOTHESIS

The purpose of this article was to determine the percentage of glenoid width restoration necessary for glenohumeral stability after Latarjet by measuring anterior humeral head translation and force distribution on the coracoid graft. The hypothesis was that at least 100% of glenoid width restoration with Latarjet would be required to maintain glenohumeral stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine cadaveric shoulders were prepared and mounted on an established shoulder simulator. A lesser tuberosity osteotomy (LTO) was performed to allow accurate removal of glenoid bone. Coracoid osteotomy was performed, and the coracoid graft was sized to a depth of 10 mm. Glenoid bone was sequentially removed, and Latarjet was performed using 2 screws to reestablish 110%, 100%, 90%, and 80% of native glenoid width. The graft was passed through a subscapularis muscle split, and the LTO was repaired. A motion tracking system recorded glenohumeral translations, and force distribution was recorded using a TekScan pressure sensor secured to the glenoid face and coracoid graft. Testing conditions included native; LTO; Bankart tear; and 110%, 100%, 90%, and 80% of glenoid width restoration with Latarjet. Glenohumeral translations were recorded while applying an anteroinferior load of 44 N at 90° of humerothoracic abduction and 0° or 45° of glenohumeral external rotation. Force distribution was recorded without an anteroinferior load.

RESULTS

Anterior humeral head translation progressively increased as the proportion of glenoid width restored decreased. A marked increase in anterior humeral head translation was found with 90% versus 100% glenoid width restoration (10.8 ± 3.0 vs 4.1 ± 2.6 mm, respectively; P < .001). Greater glenoid bone loss also led to increased force on the coracoid graft relative to the native glenoid bone after Latarjet. A pronounced increase in force on the coracoid graft was seen with 90% versus 100% glenoid width restoration (P < .001).

CONCLUSION

Anterior humeral head translation and force distribution on the coracoid graft dramatically increased when <100% of the native glenoid width was restored with a Latarjet procedure.

CLINICAL RELEVANCE

If a Latarjet is unable to fully restore the native glenoid width, surgeons should consider alternative graft sources to minimize the risk of recurrent instability or coracoid overload.

The Influence of Glenoid Bone Loss and Graft Positioning on Graft and Cartilage Contact Pressures After the Latarjet Procedure

BACKGROUND

Glenohumeral joint contact loading before and after glenoid bone grafting for recurrent anterior instability remains poorly understood.

PURPOSE

To develop a computational model to evaluate the influence of glenoid bone loss and graft positioning on graft and cartilage contact pressures after the Latarjet procedure.

STUDY DESIGN

Controlled laboratory study.

METHODS

A finite element model of the shoulder was developed using kinematics, muscle and glenohumeral joint loading of 6 male participants. Muscle and joint forces at 90° of abduction and external rotation were calculated and employed in simulations of the native shoulder, as well as the shoulder with a Bankart lesion, 10% and 25% glenoid bone loss, and after the Latarjet procedure.

RESULTS

A Bankart lesion as well as glenoid bone loss of 10% and 25% significantly increased glenoid and humeral cartilage contact pressures compared with the native shoulder (P < .05). The Latarjet procedure did not significantly increase glenoid cartilage contact pressure. With 25% glenoid bone loss, the Latarjet procedure with a graft flush with the glenoid and the humerus positioned at the glenoid half-width resulted in significantly increased humeral cartilage contact pressure compared with that preoperatively (P = .023). Under the same condition, medializing the graft by 1 mm resulted in humeral cartilage contact pressure comparable with that preoperatively (P = .097). Graft lateralization by 1 mm resulted in significantly increased humeral cartilage contact pressure in both glenoid bone loss conditions (P < .05).

CONCLUSION

This modeling study showed that labral damage and greater glenoid bone loss significantly increased glenoid and humeral cartilage contact pressures in the shoulder. The Latarjet procedure may mitigate this to an extent, although glenoid and humeral contact loading was sensitive to graft placement.

CLINICAL RELEVANCE

The Latarjet procedure with a correctly positioned graft should not lead to increased glenohumeral joint contact loading. The present study suggests that lateral graft overhang should be avoided, and in the situation of large glenoid bone defects, slight medialization (ie, 1 mm) of the graft may help to mitigate glenohumeral joint contact overloading.

Association Between Preoperative Glenoid Bone Loss and Postoperative Outcomes After Coracoid Transfer Combined With Open Bankart Repair: Comparison of the Bristow and Latarjet Techniques

Background

Whether the extent of glenoid bone loss (GBL) affects clinical outcome after coracoid process transfer (CPT) is still unclear.

Purpose

To evaluate postoperative outcomes after CPT combined with open Bankart repair in young rugby players in terms of the extent of GBL and between the Bristow and Latarjet techniques.

Study Design

Cohort study; Level of evidence, 3.

Methods

The authors investigated 101 shoulders in 91 competitive rugby players who underwent CPT combined with open Bankart repair by the Bristow (group B; 66 shoulders) or Latarjet (group L; 35 shoulders) procedure between 2007 and 2017. The extent of GBL was calculated from the en face view of the glenoid on preoperative 3-dimensional computed tomography scans and was used to categorize shoulders into 4 grades (grade 0, 0%; grade 1, >0% and ≤10%; grade 2, >10% and ≤20%; grade 3, >20%). At the minimum 2-year follow-up, the authors analyzed the relationship between GBL or GBL grade and postoperative outcome scores (American Shoulder and Elbow Surgeons score, Rowe score, Western Ontario Shoulder Instability Index, and patient satisfaction), return-to-play (RTP) times, graft failure (insufficient union or translocation), and recurrence.

Results

The mean GBL in all shoulders was 10.9% ± 9.2% and was not significantly different between the 2 groups. There were no significant correlations between GBL and any outcome measure in either group. The mean RTP time was significantly shorter in group L versus group B (4.8 ± 1.1 vs 5.8 ± 1.8 months, respectively; P = .002), but it was not associated with GBL. In group B, the rate of graft failure was not significantly higher in shoulders with grade 0 or 1 GBL versus grade 2 or 3 GBL (8 [25.0%] vs 4 [11.8%], respectively; P = .21). In group B, graft failure was confirmed in 12 shoulders (18.2%), compared with 1 shoulder (2.9%) in group L. Postoperative recurrence occurred in significantly fewer shoulders in group B than in group L (2 [3.0%] vs 5 [14.3%], respectively; P = .047).

Conclusion

The extent of GBL did not affect outcome scores after CPT, regardless of operative procedure.

Shoulder arthroplasty in patients with glenohumeral osteoarthritis, glenoid bone loss and an intact rotator cuff: an algorithmic approach and review of the literature

In patients with severe glenohumeral osteoarthritis (OA) and preserved rotator cuff function who have failed nonoperative treatment, anatomic total shoulder arthroplasty (TSA) has historically been the preferred surgical treatment. Shoulder arthroplasty in the setting of glenoid bone loss setting is technically demanding. Many techniques have been described to deal with glenoid bone loss including eccentric reaming, bone grafting, augmented glenoid baseplates, and patient-specific implants. Still, the decision to perform anatomic TSA or reverse total shoulder arthroplasty (RTSA) is often unclear, especially as the use of RTSA increases and evolves, making historical studies less useful when considering modern implant designs. RTSA has been advocated as a solution for patients with severe glenoid bone loss with intact rotator cuff function. Moreover, in appropriately selected patients, good outcomes can be achieved without the use of bone grafting or augmented baseplates. In cases of severe glenoid bone loss, RTSA can be performed with reaming the glenoid flat such that the baseplate rests on native glenoid bone. We have previously reported excellent prosthetic survival with this technique at 5-year follow-up. The purpose of this article is to highlight our suggested treatment algorithm for glenohumeral OA with glenoid bone loss and intact rotator cuff. Specifically, we focus on situations where RTSA may be preferred as opposed to anatomic TSA, and our suggested approach to managing bone loss intraoperatively in this complex patient population.

Comparison of glenoid bone grafting vs. augmented glenoid baseplates in reverse shoulder arthroplasty: a systematic review

BACKGROUND

Management of bone loss and glenoid deformity can present a significant challenge to surgeons. The purpose of this review was to compare outcomes of reverse shoulder arthroplasty (RSA) using either bone graft or augmented baseplates for the management of glenoid bone loss and deformity.

METHODS

A comprehensive search of MEDLINE, Embase, and Cochrane indices was performed for studies reporting clinical outcomes following primary RSA with bone grafting or use of augmented baseplates. Pooled and frequency-weighted means, standard deviations, and ranges were calculated and reported for comparison.

RESULTS

Overall, 19 studies and 652 patients with bone grafting (n = 401) and augmented baseplates (n = 251) were included in the study. Mean patient age and gender were 70.3 ± 3.1 years and 47% female in the bone grafting group and 72.9 ± 3.7 years and 59.0% female in the augmented baseplate group. Mean follow-up for the augmented baseplate group was 23.1 ± 8.2 months and 29.5 ± 10.1 months for the bone grafting group. Overall complication and revision rates were 11.7% and 4.5% for the bone grafting group and 11.8% and 3.7% for the augmented baseplate group. Range of motion as well as patient-reported and functional outcome scores were similar between both techniques. Infections, component loosening, and notching were 1.9%, 3.6%, and 24.6% in the bone grafting group and 0.7%, 1.6%, and 4.7% in the augmented baseplate group.

CONCLUSIONS

Glenoid bone grafting and augmented baseplates are effective treatment options for the management of bone loss and glenoid deformity. Both treatments improve overall clinical outcomes with relatively low complication rates and revision rates.

Predictors of Bone Loss in Anterior Glenohumeral Instability

BACKGROUND

Anterior shoulder instability can result in bone loss of both the anterior glenoid and the posterior humerus. Bone loss has been shown to lead to increased failure postoperatively and may necessitate more complex surgical procedures, resulting in worse clinical outcomes and posttraumatic arthritis.

HYPOTHESIS/PURPOSE

The purpose of this study was to investigate predictors of glenoid and humeral head bone loss in patients undergoing surgery for anterior shoulder instability. It was hypothesized that male sex, contact sport participation, traumatic dislocation, and higher number of instability events would be associated with greater bone loss.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 892 patients with anterior shoulder instability were prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. The presence and amount of anterior glenoid bone loss and accompanying Hill-Sachs lesions were quantified. Descriptive information and injury history were used to construct proportional odds models for the presence of any bone defect, for defects >10% of the anterior glenoid or humeral head, and for combined bony defects.

RESULTS

Anterior glenoid bone loss and Hill-Sachs lesions were present in 185 (20.7%) and 470 (52.7%) patients, respectively. Having an increased number of dislocations was associated with bone loss in all models. Increasing age, male sex, and non-White race were associated with anterior glenoid bone defects and Hill-Sachs lesions. Contact sport participation was associated with anterior glenoid bone loss, and Shoulder Actitvity Scale with glenoid bone loss >10%. A positive apprehension test was associated with Hill-Sachs lesions. Combined lesions were present in 19.4% of patients, and for every additional shoulder dislocation, the odds of having a combined lesion was 95% higher.

CONCLUSION

An increasing number of preoperative shoulder dislocations is the factor most strongly associated with glenoid bone loss, Hill-Sachs lesions, and combined lesions. Early surgical stabilization before recurrence of instability may be the most effective method for preventing progression to clinically significant bone loss. Patients should be made aware of the expected course of shoulder instability, especially in athletes at high risk for recurrence and osseous defects, which may complicate care and worsen outcomes.

REGISTRATION

NCT02075775 (ClinicalTrials.gov identifier).

A biomechanical analysis of double screw, double button and screw button fixation constructs in PSI guided Latarjet procedure

BACKGROUND

The Latarjet coracoid transfer procedure reliably stabilizes the glenohumeral joint for shoulder instability. However, complications such as graft osteolysis, non-union and fracture continue to affect patient clinical outcomes. The double screw (SS) construct is regarded as the gold standard method of fixation. SS constructs are associated with graft osteolysis. More recently, a double button technique (BB) has been suggested to minimize graft related complications. However, BB constructs are associated with fibrous non-union. To mitigate this risk, a single screw combined with a single button (SB) construct has been proposed. It is thought that this technique incorporates the strength of the SS construct and allows micromotion superiorly to mitigate stress shielding related graft osteolysis.

AIMS

The primary aim of this study was to compare the failure load of SS, BB and SB constructs under a standardized biomechanical loading protocol. The secondary aim was to characterize the displacement of each construct throughout testing.

METHODS

Computed tomography scans of twenty matched-pair cadaveric scapulae were performed. Specimens were harvested and dissected free of soft tissue. SS and BB techniques were randomly assigned to specimens for matched-pair comparison with SB trials. A patient specific instrument (PSI) guided Latarjet procedure was performed on each scapula. Specimens were tested using a uniaxial mechanical testing device under cyclic loading (100 cycles, 1Hz, 200N/s) followed by a load-to-failure protocol (0.5mm/s). Construct failure was defined by graft fracture, screw avulsion and/or graft displacement of more than 5mm.

RESULTS

Forty scapulae from twenty fresh frozen cadavers with a mean age of 69.3 years underwent testing. On average, SS constructs failed at 537.8N (SD 296.8), while BB constructs failed at 135.1N (SD 71.4). SB constructs required a significantly greater load to fail compared to BB constructs (283.5N, SD 162.8, p=0.039). Additionally, SS (1.9mm, IQR 0.87) had a significantly lower maximum total graft displacement during the cyclical loading protocol compared to SB (3.8mm, IQR 2.4, p=0.007) and BB (7.4mm, IQR 3.1, p<0.001) constructs.

CONCLUSION

These findings support the potential of the SB fixation technique as a viable alternative to SS and BB constructs. Clinically, the SB technique could reduce the incidence of loading-related graft complications seen in the first three months of BB Latarjet cases. The study is limited to time-specific results and does not account for bone union or osteolysis.

Disagreement Between the Accepted Best-Fit Circle Method to Calculate Bone Loss Between Injured and Uninjured Shoulders

BACKGROUND

No study has evaluated whether best-fit circles based on glenoids with defects accurately represent normal inferior glenoids before injury.

PURPOSE

To investigate whether the best-fit circles on the affected side with a glenoid defect can accurately represent native glenoids before injury.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

This retrospective study included 58 patients with unilateral recurrent anterior shoulder instability. First, we compared the diameter of best-fit circles based on affected and unaffected glenoids. Glenoid defect sizes based on each best-fit circle were then calculated and compared. Second, we created serial virtual glenoid defects (10%, 15%, 20%, 25%) on unaffected glenoids and compared diameters of best-fit circles on the glenoids before and after virtual defects. We also analyzed and compared the size of virtual and calculated glenoid defects. Bland-Altman plots and intraclass coefficients (ICCs) were used to compare and analyze agreement of measurements. After categorization of glenoid defects based on clinical cutoff values, Cohen κ and percentage agreement were calculated.

RESULTS

The diameter of 55.2% (32/58) of best-fit circles from affected glenoids over- or underestimated the diameter on the unaffected side by >5%. In 28 of the 32 patients, the diameter of the affected side circle was overestimated. Consequently, 41.4% (24/58) of glenoid defects were over- or underestimated by >5%. In 19 of the 24 patients, the glenoid defect from the affected side was >5% larger. ICCs between sides for best-fit circle diameters and defect sizes were 0.632 and 0.800, respectively. Agreement of glenoid defect size between sides was 58.6% (34/58) overall, but when the defect was ≥10%, agreement decreased to 32.3% (10/31). Among 232 glenoids with virtual defects created from 58 normal glenoids, the diameter of 31.0% (72/232) of best-fit circles and the size of 11.6% (27/232) of defects were over- or underestimated by >5%.

CONCLUSION

When assessing glenoid defects in anterior shoulder instability, best-fit circles based on affected glenoids do not always represent the native glenoid and may thus lead to inaccurate circle sizes and defect estimates.

Glenoid Bone Loss Pattern in Patients With Posterior Instability Versus Anterior Instability: A Matched Cohort Study

Background

The pattern of glenoid bone loss (GBL) in anterior glenohumeral instability is well described. It was recognized recently that posterior GBL after instability has a posteroinferior pattern.

Purpose/Hypothesis

The purpose of this study was to compare GBL patterns in a matched cohort of patients with anterior versus posterior glenohumeral instability. The hypothesis was that the GBL pattern in posterior instability would be more inferior than the GBL pattern in anterior instability.

Study Design

Cohort study; Level of evidence, 3.

Methods

In this multicenter retrospective study, 28 patients with posterior instability were matched with 28 patients with anterior instability by age, sex and number of instability events. GBL location was defined using a clockface model. Obliquity was defined as the angle between the long axis of the glenoid and a line tangent to the GBL. Superior and inferior GBL were measured as areas and defined relative to the equator. The primary outcome was the 2-dimensional characterization of posterior versus anterior GBL. The secondary outcome was a comparison of the posterior GBL patterns in traumatic and atraumatic instability mechanisms in an expanded cohort of 42 patients.

Results

The mean age of the matched cohorts (n = 56) was 25.2 ± 9.87 years. The median obliquity of GBL was 27.53° (interquartile range [IQR], 18.83°-47.38°) in the posterior cohort and 9.28° (IQR, 6.68°-15.75°) in the anterior cohort (P < .001). The mean superior-to-inferior bone loss ratio was 0.48 ± 0.51 in the posterior cohort and 0.80 ± 0.55 (P = .032) in the anterior cohort. In the expanded posterior instability cohort (n = 42), patients with traumatic injury mechanism (n = 22), had a similar GBL obliquity compared to patients with an atraumatic injury mechanism (n = 20) (mean, 27.73° [95% CI, 20.26°-35.20°] vs 32.20° [95% CI, 21.27°-43.14°], respectively) (P = .49).

Conclusion

Posterior GBL occurred more inferiorly and at an increased obliquity compared with anterior GBL. This pattern is consistent for traumatic and atraumatic posterior GBL. Bone loss along the equator may not be the most reliable predictor of posterior instability, and critical bone loss may be reached more rapidly than a model of loss along the equator may predict.

Factors Associated with Functional Improvement After Posteriorly Augmented Total Shoulder Arthroplasty

BACKGROUND

Posteriorly augmented glenoid components in anatomic total shoulder arthroplasty (TSA) address posterior glenoid bone loss with inconsistent results. The purpose of this study is to identify pre- and postoperative factors that impact range of motion and function after augmented TSA in patients with B2 or B3 glenoid morphology.

METHODS

A retrospective review was performed of all patients who underwent TSA with a step type augment by a single surgeon between 2009 and 2018. Patients with a Walch type B2 or B3 glenoid were included. Outcomes included forward elevation (FE), external rotation (ER), internal rotation (IR), Single Assessment Numeric Evaluation (SANE), and Visual Analog Scale for pain (VAS). Preoperative imaging was reviewed to assess glenoid retroversion and posterior humeral head subluxation relative to the scapular body and mid-glenoid face. Postoperative measurements included glenoid retroversion, subluxation relative to the scapular body, subluxation relative to the central glenoid peg, and center-peg osteolysis. Measurements were performed by investigators blinded to range of motion and functional outcome scores.

RESULTS

Fifty patients (mean age, 68.1 + 8.0) with a mean follow-up of 42.0 months (Range, 24-106 months) were included. Glenoid morphology included 41 B2 and 9 B3 glenoids. One patient had center-peg osteolysis and one patient had glenoid component loosening. The average preoperative FE, ER, and IR was 110°, 21°, and S1, respectively. The average postoperative FE, ER, and IR was 155°, 42°, and L1, respectively. The mean postoperative VAS score was 0.5 + 0.8 and mean SANE score was 94.5 + 5.6. Patients with B3 glenoids were associated with better postoperative internal rotation compared to B2 glenoids (T10 vs L1, p=0.024), with no other differences in range of motion between the glenoid types. Preoperative glenoid retroversion did not significantly impact postoperative range of motion. Postoperative glenoid component retroversion and residual posterior subluxation relative to the scapular body or glenoid face did not correlate with range of motion in any plane. However, posterior subluxation relative to the glenoid face was moderately associated with lower SANE scores (r= -0.448, p=0.006).

CONCLUSION

Patients achieved excellent functional outcomes and pain improvement after TSA with an augmented glenoid component. Postoperative range of motion and function had no clinically important associations with pre- or postoperative glenoid retroversion or humeral head subluxation in our cohort of posteriorly augmented total shoulder arthroplasties except for worse functional scores with increased humeral head subluxation in relation to the glenoid surface.

3D Printed Patient-Specific Cutting Guides for Bone Grafting in Reverse Shoulder Arthroplasty: A Novel Technique

Glenoid bone loss remains a challenge in shoulder arthroplasty. Addressing substantial bone loss is essential to ensure proper function and stability of the shoulder prosthesis and to prevent baseplate loosening and subsequent revision surgery. Current options for creating and shaping glenoid bone grafts include free-hand techniques and simple reusable cutting guides that cut the graft at a standard angle. There is currently no patient-specific device available that enables surgeons to accurately prepare the bone graft and correct glenoid deformity. We present a novel surgical technique using three-dimensional (3D)-printed cutting guides to create a patient-specific bone graft to address glenoid deformity in the setting of reverse shoulder arthroplasty.

Clinical and Radiological Outcomes in Patients With Anterior Shoulder Instability and Glenoid Bone Loss after Arthroscopic Free Bone Block Combined With Dynamic Anterior Stabilization

BACKGROUND

As an alternative to the Latarjet procedure, the arthroscopic free bone block (FBB) procedure combined with dynamic anterior stabilization (DAS) has been recently proposed to provide both glenoid augmentation and a tendon sling effect for treating anterior shoulder instability (ASI) with glenoid bone loss.

PURPOSE

To evaluate the clinical and radiological outcomes of FBB-DAS for ASI with glenoid bone loss.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent arthroscopic FBB-DAS for ASI with >15% glenoid bone loss between February 2017 and March 2020 were screened and enrolled in this study. Clinical outcome measures were assessed preoperatively and at a minimum 2-year follow-up, including recurrence, complications, shoulder functional scores, range of motion, and return to sports. Postoperative computed tomography and magnetic resonance imaging were also performed.

RESULTS

Of a total of 65 patients with a mean follow-up of 46.1 ± 13.1 months, no patients experienced a recurrent dislocation or subluxation postoperatively, while 2 had a positive anterior apprehension test (3.1%). Additionally, 2 patients (3.1%) experienced complications of hematoma and shoulder stiffness, respectively. The mean visual analog scale score, American Shoulder and Elbow Surgeons score, Rowe score, and Oxford Shoulder Instability Score all improved significantly from 3.2 ± 2.4, 75.0 ± 18.9, 43.6 ± 27.3, and 33.8 ± 9.0 preoperatively to 1.3 ± 0.8, 95.1 ± 8.0, 95.5 ± 7.8, and 14.8 ± 3.5 at final follow-up, respectively (all P < .001). No difference was detected in range of motion except for 8.1° and 7.5° external rotation limitations in adduction and abduction, respectively. There were 62 patients (95.4%) who returned to sports, and 54 patients (83.1%) returned to the preinjury level. The transferred biceps tendon was intact in all 59 patients who completed radiological examination at the latest follow-up. Good bone healing was achieved in 98.3% of patients, and the glenoid bone defect decreased from 18.1% to 4.9%. Osseous and labral glenoids were significantly enlarged in width and depth on the latest magnetic resonance imaging (all P < .001).

CONCLUSION

Arthroscopic FBB-DAS provided satisfactory clinical and radiological outcomes for ASI with glenoid bone loss. Despite slight external rotation restrictions, it achieved low recurrence and complication rates, excellent shoulder functional scores, a high return-to-sports rate, and favorable graft healing and remodeling.

Surgeon variation in glenoid bone reconstruction procedures for shoulder instability

BACKGROUND

Advances in the understanding and management of glenoid bone loss in shoulder instability have led to the development of alternative bony reconstruction techniques to the Latarjet using free bone grafts, but little is known about surgeon adoption of these procedures. This study sought to characterize surgeon variation in the use of glenoid bone reconstruction procedures for shoulder instability and ascertain reasons underlying procedure choice.

METHODS

A 9-question survey was created and distributed to 160 shoulder surgeons members of the PacWest Shoulder and Elbow Society, of whom 65 (41%) responded. The survey asked questions regarding fellowship training, years in practice, surgical volume, preferred methods of glenoid bone reconstruction, and reasons underlying treatment choice.

RESULTS

All surgeons completed a fellowship, with an equal number of sports medicine fellowship-trained (46%) and shoulder and elbow fellowship-trained (46%) physicians. The majority had been in practice for at least 6 years (6-10 years: 25%; >10 years: 59%). Most (78%) performed ≤10 glenoid bony reconstructions per year, and 66% indicated that bony procedures represented <10% of their total annual shoulder instability case volume. The open Latarjet was the preferred primary reconstruction method (69%), followed by open free bone block (FBB) (22%), arthroscopic FBB (8%), and arthroscopic Latarjet (1%). Distal tibia allograft (DTA) was the preferred graft (74%) when performing an FBB procedure, followed by iliac crest autograft (18%), and distal clavicle autograft (6%). The top 5 reasons for preferring Latarjet over FBB were the sling effect (57%), the autologous nature of the graft (37%), its robust clinical evidence (22%), low cost (17%), and availability (11%). The top 5 reasons for choosing an FBB procedure were less anatomic disruption (58%), lower complication rate (21%), restoration of articular cartilage interface (16%), graft versatility (11%), and technical ease (11%). Only 20% of surgeons indicated always performing a bony glenoid reconstruction procedure in the noncontact athlete with less than 20% glenoid bone loss. However, that percentage rose to 62% when considering a contact athlete with the same amount of bone loss.

CONCLUSIONS

Although open Latarjet continues to be the most popular glenoid bony primary reconstruction procedure in shoulder instability, nearly 30% of shoulder surgeons in the western United States have adopted FBB techniques as their preferred treatment modality--with DTA being the most frequently used graft. High-quality comparative clinical effectiveness research is needed to reduce decisional conflict and refine current evidence-based treatment algorithms.

Clinical and Radiological Outcomes after Total Shoulder Arthroplasty Using Custom-Made Glenoid Components: A Systematic Review

Reverse total shoulder arthroplasty presents itself sometimes as challenging when it comes to addressing massive bone loss, either in primary or revision settings. Custom components recently have made their way into shoulder prosthetics and are meant to help in the case of extensive glenoid bone destruction. Because of strict indication and the fairly recent introduction of these implants, the usage of custom-made glenoid implants is not very common yet. However, the early results are promising. The purpose of this review was to summarize and analyze the available literature. Therefore, a systematic review was performed according to PRISMA guidelines. A comprehensive search of the databases PubMed, Cochrane, and Livivo was performed to screen for studies reporting on clinical and radiological outcomes of custom glenoid implants. Four studies with a total of 46 shoulders were included in this review. The mean patient age was 68.8 years and the mean time of follow-up was 24.3 months. The weighted means showed an increase in CMS (32.7 points), in ASES (39.8 points), in anteversion (67.4 degrees), and in abduction (51.9 degrees) and a decrease in VAS (5.4 points). Custom-made glenoid implants are therefore a viable option in cases of large combined glenoid bone loss, both in primary and revision shoulder arthroplasty.

Arthroscopic Bankart Repair With Remplissage as an Alternative to Latarjet for Anterior Glenohumeral Instability With More Than 15% Glenoid Bone Loss

BACKGROUND

Surgical management of anterior shoulder instability continues to evolve. The clinical effectiveness of arthroscopic Bankart repair with remplissage (REMP) in patients with increasing glenoid bone loss (GBL) has not been thoroughly compared with Latarjet.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare 2-year outcomes of REMP versus open Latarjet in patients with >15% GBL. We hypothesized that there would be no difference.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A multicenter, retrospective study was performed on a consecutive series of patients who underwent primary REMP or Latarjet by 4 shoulder specialists between August 2013 and December 2019 for >15% GBL. Procedure performance was based on shared decision making between the surgeon and patient. Baseline and 2-year postoperative range of motion (ROM) and the following patient-reported outcomes (PROs) were collected: Western Ontario Shoulder Instability Index, Single Assessment Numeric Evaluation, and visual analog scale for pain. Return to sport, satisfaction, complications, recurrence, and revisions were reviewed.

RESULTS

A total of 47 patients were available for study, including 22 who underwent REMP and 25 who underwent Latarjet. Baseline demographic characteristics, ROM, and PROs were similar between the groups. Mean preoperative GBL (REMP 25.8% ± 7.8% vs Latarjet 25.1% ± 9.0%; P = .800) and off-track lesions (REMP 59.1% vs Latarjet 44.0%; P = .302) were similar. Postoperative change in external rotation favored Latarjet (10° ± 22° vs -4° ± 13°; P = .017). Postoperative PROs, return to the sports (86.4% vs 87.5%; P = .99), and satisfaction (95.5% vs 95.8%; P = .99) were similar between groups. There were no recurrent dislocations in either group. One infected hematoma was encountered in the Latarjet cohort.

CONCLUSION

At short-term follow-up, the hypothesis was upheld. REMP and Latarjet provided similar outcomes for patients with >15% GBL, although REMP patients experienced slightly decreased external rotation. Although larger series and longer-term follow-ups are required, remplissage may be considered in patients with >15% glenoid bone loss.

Augmented baseplates yield optimum outcomes when compared with bone graft augmentation for managing glenoid deformity during reverse total shoulder arthroplasty: a retrospective comparative study

PURPOSE

The purpose of this study was to compare the outcomes of primary reverse total shoulder arthroplasty (rTSA) using glenoid bone grafting (BG rTSA) with primary rTSA using augmented glenoid baseplates (Aug rTSA) with a minimum 2-year follow-up.

METHODS

A total of 520 primary rTSA patients treated with 8° posterior glenoid augments (n = 246), 10° superior glenoid augments (n = 97), or combined 10° superior/8° posterior glenoid augments (n = 177) were compared with 47 patients undergoing glenoid bone grafting for glenoid bone insufficiency. The mean follow-up was 37.0(±16) and 53.0(±27) months, respectively. Outcomes were analyzed preoperatively and at the latest follow-up using conventional statistics and stratification by minimum clinically important difference (MCID) and substantial clinical benefit (SCB) thresholds where applicable. Radiographs were analyzed for baseplate failure, and the incidences of postoperative complications and revisions were recorded.

RESULTS

The glenoid Aug rTSA cohort had greater improvements in patient-reported outcome measures (PROMs) and range of motion when compared with the BG rTSA group at a minimum of 2-year follow-up, including Simple Shoulder Test, Constant score, American Shoulder and Elbow Surgeons score, University of California Los Angeles score, Shoulder Pain and Disability Index score, shoulder function, Shoulder Arthroplasty Smart score, abduction, and external rotation (P < .05). Patient satisfaction was higher in the Aug rTSA group compared with the BG rTSA group (P = .006). The utilization of an augmented glenoid component instead of glenoid bone grafting resulted in approximately 50% less total intraoperative time (P < .001), nearly 33% less intraoperative blood loss volume (P < .001), approximately 3-fold less scapular notching (P < .01), and approximately 15-fold less adverse events requiring revision (P < .01) when compared with the BG rTSA cohort. Aside from SCB for abduction, the Aug rTSA cohort achieved higher rates of exceeding MCID and SCB for every PROM compared with BG rTSA. More specifically, 77.6% and 70.2% of the Aug rTSA achieved SCB for American Shoulder and Elbow Surgeons and Shoulder Pain and Disability Index vs. 55% and 48.6% in the BG rTSA, respectively (P = .003 and P = .013).

CONCLUSION

The present midterm clinical and radiographic study demonstrates that the utilization of an augmented baseplate for insufficient glenoid bone stock is superior as judged by multiple PROMs and range of motion metrics when compared with bone graft augmentation at minimum 2-year follow-up. In addition, when analyzed according to MCID and SCB thresholds, the use of augmented baseplates outperforms the use of glenoid bone grafting. Complication and revision rates also favor the use of augmented glenoid baseplates over glenoid bone grafting. Long-term clinical and radiographic follow-up is necessary to confirm that these promising midterm results are durable.

How to Fashion the Bone Block for Reconstruction of the Glenoid in Anterior and Posterior Instability

BACKGROUND

Glenoid restoration techniques to address glenohumeral instability-induced anterior and posterior glenoid bone loss (AGBL and PGBL) often require reconstruction, but best-fit bone block (BFBB) modeling has not been developed.

PURPOSE

To provide glenoid bony reconstruction models for anterior and posterior instability of the shoulder using a bone loss instability cohort with high-fidelity 3-dimensional (3D) imaging.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We reviewed consecutive patients indicated for operative stabilization who had posterior glenohumeral instability and suspected GBL who underwent 2-dimensional (2D) computed tomography (CT). Patients were matched by sex, laterality, and age to patients who underwent operative stabilization of anterior glenohumeral instability. Mimics software was used to convert all 2D CT scans into 3D models of the scapula. A BFBB model was designed to digitally reconstruct GBL and was used to predict the amount, anatomic configuration, and fixation configuration of bony reconstruction required in AGBL and PGBL.

RESULTS

The study included 30 patients with posterior instability and 30 patients with anterior instability; the participants' mean ± SD age was 28.8 ± 8.15 years (range, 16.0-51.0 years). Mean surface area of AGBL was 24.9% ± 7.7% (range, 14.7%-39.1%). Mean BFBB dimensions to reconstruct the anterior glenoid were determined to be a superior-inferior length of 23.9 ± 4.2 mm, anterior-posterior width of 6.4 ± 2.4 mm, and height of 1 cm. Mean angle of AGBL bone block interface relative to glenoid to reconstruct the native concavity was 79.4°± 5.9°. For PGBL, the mean surface area was 9.2% ± 5.6% (range, 3.0%-26.3%). Mean BFBB dimensions to reconstruct the posterior glenoid were a superior-inferior length of 21.9 ± 3.4 mm, width of 4.5 ± 2.3 mm, and height of 1 cm. The mean angle of PGBL bone block interface relative to the glenoid to reconstruct the native concavity was 38.6°± 14.3°. Orientation relative to the vertical glenoid axis was 77.2°± 13.8° in anterior reconstructions versus 105.9°± 10.9° in posterior reconstructions.

CONCLUSION

Patients with anterior instability required a more rectangular BFBB with a bone block-glenoid interface angle of 79°, whereas patients with posterior instability required a more trapezoidal, obtusely oriented BFBB with a bone block-glenoid interface angle of 39°. BFBBs for either AGBL or PGBL can be effectively designed, and their size and/or shape can be predicted based on approximate percentage of GBL.

Biomechanical comparison between various screw fixation angles for Latarjet procedure: a cadaveric biomechanical study

BACKGROUND

The Latarjet procedure is a reliable treatment for the management of anterior glenohumeral instability with glenoid bone loss. However, the biomechanical properties of different fixation angles between screw and glenoid surface (α angle) have rarely been studied. The aim of the study was to investigate and compare the fixation stability, failure load, and failure mechanism between different α angles for Latarjet procedures, which were performed on cadaver specimens.

METHODS

Twenty-four shoulder specimens (8 in each of 3 groups) were dissected free of all soft tissue, and a 25% glenoid defect was created. The coracoid process was osteomized and fixed with 2 screws at 3 different α angles: 0° (group A), 15° (group B), and 30° (group C). Specimens were mounted to a testing apparatus, and cyclic loading (100 cycles at 1 Hz) was applied with a staircase protocol (50, 100, 150, and 200 N). Gross graft displacement and interface displacement were measured. The ultimate failure loads and failure mechanisms were recorded.

RESULTS

There was no significant difference in gross displacement under any cyclic load between 3 groups. However, a significant larger interface displacement was noted in group C than in group A in 150-N cyclic loading (P = .017). Under failure strength testing, all 24 specimens failed because of screw cutout from the glenoid, and the ultimate failure load was similar among the three groups.

CONCLUSION

Compared with the 0° α angle, the displacement after cyclic loading did not significantly increase when the α angle was increased to 15° but significantly increased at 30° for Latarjet procedures, which were performed on cadaver specimens. The results suggest that surgeons should apply the screws as parallel as possible to the glenoid surface when performing the Latarjet procedure. Although mild deviation may not reduce fixation stability, α angles greater than 30° should be avoided.

High rate of return to sport and excellent patient-reported outcomes after an open Latarjet procedure

HYPOTHESIS

The purpose of this study was to report return to sport, patient-reported outcomes (PROs), subjective outcomes, and complications or failures in patients who underwent open Latarjet surgery.

METHODS

Patients who underwent open Latarjet surgery performed by 2 fellowship-trained surgeons between August 2006 and November 2018 were included. Prospectively collected data were reviewed. Recurrent instability and revision surgical procedures were recorded. Subjective outcomes included return to sport and fear of reinjury or activity modification as a result of patients' instability history. PROs included the American Shoulder and Elbow Surgeons (ASES) score, Short Form 12 Physical Component Summary score, Single Assessment Numeric Evaluation score, Quick Disabilities of the Arm, Shoulder and Hand score, and satisfaction. Age, sex, sports participation, pain, primary vs. revision surgery (prior failed arthroscopic or open Bankart repair), dislocation number, glenoid bone loss, glenoid track concept, and projected glenoid track were evaluated. Failure was defined as an ASES score <70, recurrent dislocation, or revision instability surgery.

RESULTS

A total of 126 shoulders (125 patients) met the inclusion criteria, with a mean age of 28.1 years (range, 15-57 years). Of 126 shoulders, 7 (5.5%) underwent additional procedures prior to final follow-up and were excluded from outcome analyses; failure occurred in 6 of these shoulders. Mean follow-up data at 3.7 years (range, 2-9.3 years) were attained in 86.6% of patients (103 of 119). All PROs significantly improved from preoperative baseline (ASES score, from 69.7 to 90.2; Single Assessment Numeric Evaluation score, from 55.8 to 85.9; and Quick Disabilities of the Arm, Shoulder and Hand score, from 28.4 to 10.5). PROs did not differ based on sex, sports participation type, dislocation with or without sports, primary vs. revision procedure, and preoperative dislocation number. No correlations existed between PROs and age, glenoid bone loss, or number of previous surgical procedures. On-track lesions (50 of 105, 47.6%) and projected on-track lesions (90 of 105, 85.7%) correlated with better patient satisfaction but not PROs. Despite not having recurrences, 63 of 99 patients (63.6%) reported activity modifications and 44 of 99 patients (44.4%) feared reinjury. These groups had statistically worse PROs, although the minimal clinically important difference was not met. Return to sport was reported by 97% of patients (86 of 89), with 74% (66 of 89) returning at the same level or slightly below the preinjury level. Revision stabilization surgery was required 6 of 126 cases (4.8%), and 6 of 103 shoulders (5.8%) had ASES scores <70.

CONCLUSION

The open Latarjet procedure led to significant improvements in all PROs, and overall, 97% of patients returned to sport. Fear of reinjury and activity modifications were common after open Latarjet procedures but did not appear to affect clinical outcomes. On-track and projected on-track measurements correlated with better patient satisfaction but not improved PROs.

Glenoid Bone Loss Directly Affects Hill-Sachs Morphology: An Advanced 3-Dimensional Analysis

BACKGROUND

While the glenoid track concept presents a useful prediction for recurrent glenohumeral instability, little is known about the humeral head bony architecture as it relates to glenoid erosion in the setting of bipolar bone loss.

PURPOSE

To (1) qualitatively and quantitatively analyze the interplay between glenoid bone loss (GBL) and Hill-Sachs lesions (HSLs) in a cohort of patients with anterior instability using 3-dimensional imaging software and (2) assess the relationships between GBL and HSL characteristics.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Patients were identified who had anterior shoulder instability with a minimum 5% GBL and evidence of HSL confirmed on computed tomography. Unilateral 3-dimensional models of the ipsilateral proximal humeral head and en face sagittal oblique view of the glenoid were reconstructed using MIMICS software (Materialise NV). GBL surface area, width, defect length, and glenoid track width were quantified. The volume, surface area, width, and depth of identified HSLs were quantified with their location (medial, superior, and inferior extent) on the humeral head. Severity of GBL was defined as percentage glenoid bone surface area loss and categorized as low grade (5%-10%), moderate grade (>10% to 20%), high grade (>20% to 30%), and extensive (>30%). Analysis of variance was then computed to determine significance (P < .05) between severity of GBL and associated HSL parameters.

RESULTS

In total, 100 patients met inclusion criteria (mean age, 27.9 years; range, 18-43 years), which included 58 right shoulders and 42 left shoulders (84 male, 16 female). Among groups, there were 32 patients with low-grade GBL (mean GBL = 6.1%), 38 with moderate grade (mean GBL = 16.2%), 17 with high grade (mean GBL = 23.7%), and 13 with extensive (mean GBL = 34.0%), with an overall mean GBL of 18.1% (range, 5%-39%). Patients with 5%-10% GBL had significantly narrower HSLs (average and maximum width; P < .03) and deeper HSLs (average depth; P = .002) as compared with all other GBL groups, while greater GBL was associated with wider and shallower HSLs. GBL width, percentage width loss, defect length, and glenoid track width all significantly differed across the 4 GBL groups (P < .05).

CONCLUSION

HSLs had significantly different morphological characteristics depending on the severity of GBL, indicating that GBL was directly related to the characteristics of HSLs. Patients presenting with smaller glenoid defects had significantly narrower and deeper HSLs with less humeral head surface area loss, while greater GBL was associated with wider and shallower HSLs.

Editorial Commentary: Buttoning Up After Recurrent Anterior Shoulder Instability: The Eden-Hybinette Procedure Is an Effective Salvage After Failed Latarjet

Operative management of anterior glenohumeral dislocation can confer significant improvements in subjective shoulder function, pain, and overall stability. Although the coracoid-based Latarjet procedure has long been considered the ultimate treatment for complex anterior shoulder instability with glenoid or bipolar bone loss, few authors have considered the unimaginable question: what do you do when a patient fails Latarjet? A modified arthroscopic technique of the Eden-Hybinette procedure allows for revision anterior glenoid augmentation of critical glenoid bone loss with autologous tricortical iliac crest, while suture button fixation may obviate hardware complications previously seen with bicortical screw fixation. Although distal tibial allograft provides excellent congruity, viable articular cartilage, and no harvest site morbidity, financial costs and graft availability must also be considered. With favorable patient-reported outcomes, excellent rates of radiographic union, and reliable return to sport, the Eden-Hybinette procedure with suture button-based construct offers a viable alternative for patients with advanced glenoid bone loss (>20%) or revision scenarios.

Lateralized glenosphere reverse shoulder arthroplasty: inlay and onlay designs have similar clinical outcomes in patients with glenohumeral osteoarthritis

BACKGROUND

Whether or how the position of the humeral tray (inlay or onlay) in reverse shoulder arthroplasty (RSA) affects outcomes is unclear. Our goal was to compare the clinical and radiographic results of RSA systems with inlay vs. onlay designs but with similar neck shaft angles (NSAs) and lateralized glenospheres.

METHODS

We screened the institutional database at our tertiary academic center for patients who underwent primary RSA (with a lateralized glenosphere and a 135° NSA) from 2009 through 2017. The indication for surgery was glenohumeral osteoarthritis with glenoid bone loss (Walch classification A2, B2, B3, or C) and an intact rotator cuff. All patients were followed for a minimum of 2 years (mean, 47 months; range, 24-123 months). The humeral tray design was inlay for 79 patients and onlay for 71. All patients underwent preoperative and postoperative evaluations, including physical examination, radiography, and patient-reported outcome measures (visual analog scale for pain, American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and Western Ontario Osteoarthritis of the Shoulder index).

RESULTS

Compared with preoperative values, both groups achieved minimal clinically important differences in range of motion and patient-reported outcomes at the final follow-up. We found no significant differences between groups in any of these measures at the final follow-up. Rates of revision (inlay, 3.8% vs. onlay, 1.4%), scapular notching (inlay, 5.1% vs. onlay, 7.0%), acromial stress fracture (inlay, 0% vs. onlay, 2.8%), and tuberosity resorption (inlay, 25% vs. onlay, 27%) were not significantly different between groups (all, P > .05).

CONCLUSION

For patients with glenohumeral osteoarthritis with glenoid bone loss and an intact rotator cuff who underwent RSA using a lateralized glenosphere prosthesis with a 135° NSA, there were no significant differences between the inlay and onlay groups for range of motion, patient-reported outcomes, or complication rates. These findings are limited to this off-label indication for RSA.

Comparison of Glenoid Bone Grafting versus Augmented Glenoid Baseplates in Reverse Shoulder Arthroplasty: A Systematic Review

BACKGROUND

Management of bone loss and glenoid deformity can present a significant challenge to surgeons. The purpose of this review was to compare outcomes of reverse shoulder arthroplasty (RSA) using either bone graft or augmented baseplates for the management of glenoid bone loss and deformity.

METHODS

A comprehensive search of MEDLINE, Embase, Cochrane indices was performed for studies reporting clinical outcomes following primary RSA with bone grafting or use of augmented baseplates. Pooled and frequency-weighted means were calculated where applicable. Between-group comparison was also performed.

RESULTS

Overall, 19 studies and 652 patients were included in the study. There were no significant differences in age or gender between the bone grafting (70.3 years; 47.8% female) and augmented baseplate (72.9 years; 59.0% female) groups (p=0.166; p=0.659). Overall complication and revision rates were similar for reverse shoulder arthroplasty (RSA) using either bone graft (11.7% complication rate; 4.5% revision rate) or augmented baseplates (11.8% complication rate; 3.7% revision rate) for the management of glenoid bone loss and deformity (p=0.968; p=0.562). Furthermore, range of motion as well as patient-reported and functional outcome scores were similar between both techniques. However, infections (0.7% augmented baseplate; 1.9% bone grafting) and notching (4.7% augmented baseplate; 24.6% bone grafting) were found to be more common in the bone grafting group (p=0.012; p=0.018).

CONCLUSIONS

Glenoid bone grafting and augmented baseplates have similar overall clinical outcomes, complication rates, and revision rates. However, there were some significant differences between groups with respect to notching and infections which deserve consideration and further exploration.

Anterior Shoulder Instability Part II-Latarjet, Remplissage, and Glenoid Bone-Grafting-An International Consensus Statement

PURPOSE

The purpose of this study was to establish consensus statements via a modified Delphi process on the Latarjet procedure, remplissage, and glenoid-bone grafting for anterior shoulder instability.

METHODS

A consensus process on the treatment utilizing a modified Delphi technique was conducted, with 65 shoulder surgeons from 14 countries across 5 continents participating. Experts were assigned to one of 9 working groups defined by specific subtopics of interest within anterior shoulder instability.

RESULTS

The technical approaches identified in the statements on the Latarjet procedure and glenoid bone-graft were that a subscapularis split approach should be utilized, and that it is unclear whether a capsular repair is routinely required. Furthermore, despite similar indications, glenoid bone-grafting may be preferred over the Latarjet in patients with bone-loss greater than can be treated with a coracoid graft, and in cases of surgeon preference, failed prior Latarjet or glenoid bone-grafting procedure, and epilepsy. In contrast, the primary indications for a remplissage procedure was either an off-track or engaging Hill-Sachs lesion without severe glenoid bone loss. Additionally, in contrast to the bone-block procedure, complications following remplissage are rare, and loss of shoulder external rotation can be minimized by performing the tenodesis via the safe-zone and not over medializing the fixation.

CONCLUSION

Overall, 89% of statements reached unanimous or strong consensus. The statements that reached unanimous consensus were the prognostic factors that are important to consider in those undergoing a glenoid bone-grafting procedure including age, activity level, Hill-Sachs Lesion, extent of glenoid bone-loss, hyperlaxity, prior surgeries, and arthritic changes. Furthermore, there was unanimous agreement that it is unclear whether a capsular repair is routinely required with a glenoid bone graft, but it may be beneficial in some cases. There was no unanimous agreement on any aspect related to the Latarjet procedure or Remplissage.

LEVEL OF EVIDENCE

Level V, expert opinion.

Arthroscopic Latarjet: 2 or 4 Cortical Buttons for Coracoid Fixation? A Case-Control Comparative Study

BACKGROUND

While 2 screws are traditionally used for coracoid bone block fixation, no gold standard technique has yet been established when using cortical buttons.

PURPOSE

To compare anatomic and clinical outcomes of the arthroscopic Latarjet procedure using either 2 or 4 buttons for coracoid bone block fixation.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 23 patients with 4-button fixation (group 4B) were matched for age at surgery, sex, and follow-up to 46 patients who had 2-button fixation (group 2B). All patients underwent guided arthroscopic Latarjet (using coracoid and glenoid guides), and a tensioning device was used to rigidify the suture button construct and get intraoperative bone block compression. The primary outcome was assessment of bone block positioning and healing using computed tomography scans performed at 2 weeks and at least 6 months after surgery. The mean ± standard deviation follow-up was 49 ± 7 months (range, 24-64 months).

RESULTS

The bone block healing rate was similar in both groups: 91% in group 4B versus 95.5% in group 2B. The transferred coracoid was flush to the glenoid surface in 21 patients (91%) in group 4B and 44 patients (96%) in group 2B (P = .6); it was under the equator in 22 patients (96%) in group 4B and 44 patients (96%) in group 2B (P≥ .99). There was no secondary bone block displacement; the rate of bone block resorption was similar between the groups: 28% in group 4B and 23% in group 2B (P = .71). Patient-reported outcomes, return to sports, and satisfaction were also similar between the groups. The operating time was significantly longer in group 4B (95 vs 75 minutes; P = .009).

CONCLUSION

A 4-button fixation technique did not demonstrate any anatomic or clinical advantages when compared with a 2-button fixation technique, while making the procedure more complex and lengthening the operating time by 20 minutes. A 2-button fixation is simple, safe, and sufficient to solidly fix the transferred coracoid bone block. The use of drill guides allows accurate graft placement, while the use of a tensioning device to rigidify the suture button construct provides high rates of bone block healing with both techniques (>90%).

Functional and Radiological Outcomes after Treatment with Custom-Made Glenoid Components in Revision Reverse Shoulder Arthroplasty

Glenoid implant position and fixation are challenging in severe glenoid defects in reverse total shoulder arthroplasty (rTSA). Custom-made glenoid implants are metal augmented implants that are specially produced for a certain defect. They provide the restoration of the joint line and proper fixation. This retrospective data analysis investigated the clinical and radiological outcomes after revision using custom-made glenoid implants. Between 2018 and 2020, nine patients (10 shoulders) with severe glenoid defects underwent revision rTSA using a custom-made glenoid implant (Materialise Glenius or Lima ProMade). The pre- and postoperative Constant Murley Score (CMS), UCLA Score and Subjective Shoulder Value (SSV) were assessed. Postoperative CT scans and X-rays in two planes were available. The minimum follow-up was 12 months, with a mean follow-up of 23.1 months. The mean preoperative CMS, UCLA Score and SSV were 10.9, 4.1 and 11.0, respectively. The mean postoperative CMS, UCLA Score and SSV showed significant increases of 51.7 (<0.001), 22.9 (<0.001) and 52.0 (<0.001), respectively. There were no signs of loosening implants or scapular notching, and no revision was necessary. This trial showed promising clinical and radiological short-term outcomes for custom-made glenoid components in revision rTSA.

Glenohumeral osteoarthritis with intact rotator cuff treated with reverse shoulder arthroplasty: a systematic review

BACKGROUND

Although reverse shoulder arthroplasty (RSA) has shown satisfactory outcomes in rotator cuff-deficient shoulders, its performance in shoulders with an intact rotator cuff has not been fully elucidated. Shoulder osteoarthritis can present with alterations in glenoid morphology, which have contributed to inconsistent outcomes in anatomic shoulder replacement. The glenoid component is responsible for a predominance of these arthroplasty complications. Given these glenoid-related difficulties, RSA may provide a more favorable option. We aimed to summarize the current literature on rotator cuff intact osteoarthritis treated with primary RSA and to determine whether morphologic changes in the glenoid led to inferior outcomes.

METHODS

A literature search was performed using an inclusion criterion of primary RSA for osteoarthritis with an intact rotator cuff. The Modified Coleman Methodology Score was calculated to analyze reporting quality. Following appropriate exclusions, of the 1002 studies identified by the databases, 13 were selected.

RESULTS

Postoperative improvement in weighted means for Constant scores reached statistical significance (P = .02). The mean rate of major complications was 3.8%. A subset of 8 studies was created that detailed the following descriptions of altered glenoid morphology: "static posterior instability," "severe posterior subluxation," "posterior glenoid wear >20°," "significant posterior glenoid bone loss," "biconcave glenoid," "B2 glenoid," and "B/C glenoid." Within this subset, the mean complication rate was 4.7%, with 4 of the 7 studies having a rate ≤ 3%, and improvements in the Constant score (P = .002) and external rotation (P = .02) reached statistical significance.

DISCUSSION

RSA as treatment for osteoarthritis with an intact rotator cuff provides optimal outcomes with low complication rates across a short term of follow up. Preoperative considerations for using reverse arthroplasty in the treatment of osteoarthritis with an intact rotator cuff include glenoid retroversion, posterior humeral subluxation, and glenoid bone loss. The attributes of reverse arthroplasty that contribute to favorable outcomes in arthritic shoulders include its semiconstrained design and robust glenoid fixation. Soft-tissue imbalances as a consequence of pathologic glenoid morphology and chronic humeral subluxation can be mitigated with the RSA semiconstrained design. Glenoid bone loss can be effectively managed with RSA's robust glenoid fixation, with and without the use of bone graft. The capability to lateralize the joint center of rotation may be valuable when faced with a medialized glenoid wear pattern. The current findings suggest that reverse arthroplasty can achieve highly favorable outcomes for glenohumeral osteoarthritis with an intact rotator cuff.

Posterior glenoid bone block transfer for posterior shoulder instability: a systematic review

BACKGROUND

The purpose of this study is to systematically review the literature and evaluate patient-reported outcomes and complication/revision rates of bone block augmentation in the treatment of posterior shoulder instability (PSI).

METHODS

PubMed was searched according to PRIMSA guidelines to find clinical studies evaluating patient-reported outcomes, revision, and complication rates in posterior bone block for PSI. A literature search of MEDLINE, EMBASE, and the Cochrane Library was performed based on the PRISMA guidelines. Clinical studies reporting on the complications following posterior bone block were included.

RESULTS

Overall, 11 studies (level of evidence [LOE] III: 2, LOE IV: 9) met inclusion criteria, with 225 shoulders. Recurrent instability after the posterior bone block was found to be 9.8%. The overall complication rate was 13.8%, with 0.89% having graft complications, 11.1% having hardware complications, 0.4% having wound complications, 0.4% having nerve complications, and 0.89% having other complications. Residual pain was found in 11.6% of shoulders operated on. Patient-reported outcomes were evaluated most commonly by Rowe (81.4%), Constant (84.6%), and Walch-Duplay scores (81.6%).

CONCLUSION

There is a moderate rate of recurrence following posterior bone block for PSI. However, the patient-reported outcomes are high despite there being commonly reported persistent shoulder pain postoperatively.