Comparison of reconstructive procedures for glenoid bone loss associated with recurrent anterior shoulder instability

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.

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.

The Radius of Curvature of the Inferior Distal Clavicle Is Similar to That of the Glenoid in Both the Axial and Coronal Planes and Similar to the Inferior Coracoid

Purpose

The purposes of this study were to use computed tomography (CT) scans to compare the radius of curvature (ROC) of the inferior concave surface of the distal clavicle to the glenoid, determine graft dimensions, and compare the ROC of the congruent-arc distal clavicle autograft (DCA) to the congruent-arc Latarjet graft.

Methods

Patients who underwent bony glenoid reconstruction via a Laterjet procedure between January 2018 and January 2023 at a single institution were retrospectively identified. CT scans were used to measure the ROC of the glenoid on the axial and coronal sequences, measure the ROC of the distal clavicle on the sagittal oblique sequences, and determine the dimensions of the distal clavicle and coracoid graft.

Results

A total of 42 patients were included (Latarjet, n = 22; control, n = 20). The mean ROC of the inferior surface of the distal clavicle was not significantly different from the ROC of the glenoid in the coronal (P = .15) or axial planes (P = .65). The ROC of the coracoid when measured in the sagittal plane was not significantly different from the ROC of the distal clavicle (P = .25). The length, depth, and surface area of the coracoid in the congruent arc orientation were significantly larger than the distal clavicle (P < .005). Patients in the control group tended to have both a larger inferior clavicle ROC and a larger coracoid ROC compared to the Latarjet group (32.8 mm vs 29.6 mm, P < .0001; 31.8 mm vs 30.9 mm, P = .02).

Conclusions

The ROC of the inferior distal clavicle is similar to that of the glenoid in both the axial and coronal planes and similar to the inferior coracoid.

Clinical Relevance

CT analysis reveals that the congruent-arc DCA technique provides a robust graft with dimensions that are suitable for reconstruction of the anterior glenoid.

Distal Clavicle Autograft Versus Traditional and Congruent Arc Latarjet Procedures: A Comparison of Surface Area and Glenoid Apposition With 3-Dimensional Computed Tomography and 3-Dimensional Magnetic Resonance Imaging

BACKGROUND

Limited studies have compared graft-glenoid apposition and glenoid augmentation area between the Latarjet procedure and distal clavicle graft in glenohumeral stabilization. Additionally, preoperative planning is typically performed using computed tomography (CT), and few studies have used 3-dimensional (3D) magnetic resonance imaging (MRI) reformations to assess graft dimensions.

PURPOSE

The purpose of this study was 2-fold: (1) to compare bony apposition, glenoid augmentation, and graft width among coracoid and distal clavicle bony augmentation techniques and (2) to determine the viability of 3D MRI to assess bone graft dimensions.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 24 patients with recurrent glenohumeral instability and bone loss were included in this study. 3D CT and 3D MRI reformations were utilized to measure pertinent dimensions for 5 orientations of coracoid and distal clavicle autografts: (1) standard Latarjet procedure (SLJ), (2) congruent arc Latarjet procedure (CLJ), (3) distal clavicle attached by its posterior surface (DCP), (4) distal clavicle attached by its inferior surface (DCI), and (5) distal clavicle attached by its resected end (DCR). Glenoid augmentation was defined as the graft surface area contributing to the glenoid. Bone-on-bone apposition was defined as the graft-glenoid contact area for bone healing potential, and graft width was pertinent for fixation technique. Glenoid bone loss ranged from 0% to 34%. Paired t tests were used to compare graft sizes between patients and compare 3D CT versus 3D MRI measurements.

RESULTS

The CLJ had the largest graft surface area (mean, 318.41 ± 74.44 mm²), while the SLJ displayed the most bone-on-bone apposition (mean, 318.41 ± 74.44 mm²). The DCI had the largest graft width (mean, 20.62 ± 3.93 mm). Paired t tests revealed no significant differences between the Latarjet techniques, whereas distal clavicle grafts varied significantly with orientation. All 3D CT and 3D MRI measurements were within 1 mm of each other, and only 2 demonstrated a statistically significant difference (coracoid width: 13.03 vs 13.98 mm, respectively [P = .010]; distal clavicle thickness: 9.69 vs 10.77 mm, respectively [P = .002]). 3D CT and 3D MRI measurements demonstrated a strong positive correlation (r > 0.6 and P < .001 for all dimensions).

CONCLUSION

Glenoid augmentation, bony apposition, and graft width varied with coracoid or distal clavicle graft type and orientation. Differences between 3D CT and 3D MRI were small and likely not clinically significant.

CLINICAL RELEVANCE

3D MRI is a viable method for preoperative planning and graft selection in glenoid bone loss.

Glenoid bone augmentation: a contemporary and comprehensive systematic review of open procedures

Introduction

There is a trend towards arthroscopically treating shoulder instability with glenoid deficiency. Despite this, there remains the option for treatment through an open technique. Multiple bone augmentation options are available for recurrent anterior shoulder instability.

Objective

To provide a systematic review of recent studies for recurrent anterior shoulder instability necessitating glenoid bone augmentation specifically through open procedures using coracoid bone or free bone blocks [iliac crest bone autograft/allograft or distal tibia allograft (DTA)].

Methods

PubMed, Cochrane, EMBASE, and Google Scholar were searched for studies reporting open glenoid bone augmentation procedures with iliac crest, tibia, or coracoid bones within 10 years. Extracted data included study/patient characteristics, techniques, prior surgeries, prior dislocations, radiographic findings, range of motion (ROM), recurrent instability, patient-reported outcomes, and complications.

Results

92 met inclusion criteria (5693 total patients). Six were studies of iliac crest bone, four of DTA, and 84 using the coracoid bone. 29 studies measured postoperative arthritis showing no development or mild arthritis. 26 studies reported postoperative graft position. 62 studies reported ROM noting decline in internal/external rotation. 87 studies measured postoperative instability with low rates. Rowe Scores with noted improvement across 31/59 (52.5%) studies were seen. Common post operative complications included infection, hematoma, graft fracture, nerve injury, pain, and screw-related irritation.

Conclusion

Despite a trend towards arthroscopic management of recurrent anterior shoulder instability with glenoid deficiency, open procedures continue to provide satisfactory outcomes. Additionally, studies have demonstrated safe and efficacious use of free bone block graft options in the primary and revision setting.

Comparison of two coracoid process transfer techniques on stress shielding using three-dimensional finite-element model

Background

We created patient-based 3D finite-element (FE) models that simulate the congruent-arc Latarjet (CAL) and traditional Latarjet (TL) procedures and then compared their stress distribution patterns with different arm positions and glenoid defects.

Methods

The computed tomography data of 10 adult patients (9 men and 1 woman, ages: 18–50 years) were used to develop the 3D FE glenohumeral joint models. Twenty-five and 35% bony defects were created on the anterior glenoid rim, and the coracoid process was transferred flush with the glenoid by the traditional and congruent-arc techniques using two half-threaded screws. A load was applied to the greater tuberosity toward the center of the glenoid, and a tensile force (20 N) was applied to the coracoid tip along the direction of the conjoint tendon. The distribution patterns of the von Mises stress in the traditional and congruent-arc Latarjet techniques were compared.

Results

The mean von Mises on the graft was significantly greater for the TL technique than for the CAL. While the von Mises stress was greater in the distal medial part of the graft in the TL models, a higher stress concentration was observed in the distal lateral edge of the coracoid graft in the CAL models. The proximal medial part of the graft exhibited significantly lower von Mises stress than the distal medial part when compared according to technique, defect size, and arm position. Increasing the glenoid defect from 25 to 35% resulted in a significant increase in stress on the lateral side of the graft in both models.

Conclusion

The stress distribution patterns and stress magnitude of the coracoid grafts differed according to the procedure. Due to placing less stress on the proximal–medial part of the graft, the CAL technique may lead to insufficient stimulation for bone formation at the graft–glenoid interface, resulting in a higher incidence of graft osteolysis.

Clinical relevance The CAL technique may lead to a higher incidence of graft osteolysis.

Level of evidence

Basic Science Study; Computer Modeling.

Comparison of the Coracoid, Distal Clavicle, and Scapular Spine for Autograft Augmentation of Glenoid Bone Loss: A Radiologic and Cadaveric Assessment

BACKGROUND

Glenohumeral instability caused by bone loss requires adequate bony restoration for successful surgical stabilization. Coracoid transfer has been the gold standard bone graft; however, it has high complication rates. Alternative autologous free bone grafts, which include the distal clavicle and scapular spine, have been suggested.

STUDY DESIGN

Controlled laboratory study.

PURPOSE

The purpose of this study was to determine the percentage of glenoid bone loss (GBL) restored via coracoid, distal clavicle, and scapular spine bone grafts using a patient cohort and a cadaveric evaluation.

METHODS

Autologous bone graft dimensions from a traditional Latarjet, congruent arc Latarjet, distal clavicle, and scapular spine were measured in a 2-part study using 52 computed tomography (CT) scans and 10 unmatched cadaveric specimens. The amount of GBL restored using each graft was calculated by comparing the graft thickness with the glenoid diameter.

RESULTS

Using CT measurements, we found the mean percentage of glenoid restoration for each graft was 49.5% ± 6.7% (traditional Latarjet), 45.1% ± 4.9% (congruent arc Latarjet), 42.2% ± 7.7% (distal clavicle), and 26.2% ± 8.1% (scapular spine). Using cadaveric measurements, we found the mean percentage of glenoid restoration for each graft was 40.2% ± 5.0% (traditional Latarjet), 53.4% ± 4.7% (congruent arc Latarjet), 45.6% ± 8.4% (distal clavicle), and 28.2% ± 7.7% (scapular spine). With 10% GBL, 100% of the coracoid and distal clavicle grafts, as well as 88% of scapular spine grafts, could restore the defect (P < .001). With 20% GBL, 100% of the coracoid and distal clavicle grafts but only 66% of scapular spine grafts could restore the defect (P < .001). With 30% GBL, 100% of coracoid grafts, 98% of distal clavicle grafts, and 28% of scapular spine grafts could restore the defect (P < .001). With 40% GBL, a significant difference was identified (P = .001), as most coracoid grafts still provided adequate restoration (congruent arc Latarjet, 82.7%; traditional Latarjet, 76.9%), but distal clavicle grafts were markedly reduced, with only 51.9% of grafts maintaining sufficient dimensions.

CONCLUSIONS

The coracoid and distal clavicle grafts reliably restored up to 30% GBL in nearly all patients. The coracoid was the only graft that could reliably restore up to 40% GBL.

CLINICAL RELEVANCE

With "subcritical" GBL (>13.5%), all autologous bone grafts can be used to adequately restore the bony defect. However, with "critical" GBL (≥20%), only the coracoid and distal clavicle can reliably restore the bony defect.

Arthroscopic Distal Clavicular Autograft for Congruent Glenoid Reconstruction

Arthroscopic distal clavicular autograft (DCA) is effective in shoulder instability with glenoid bone loss. The original technique uses an osteochondral autograft, fixed with screws or suture anchors. We developed a modified procedure called "congruent arc DCA" characterized by (1) use of drilling guides to optimize graft positioning and make the all-arthroscopic procedure safer and reproducible; (2) rotation of the DCA of 90° to reach a congruent arc with its undersurface; (3) fixation of the graft with cortical buttons to simplify its intra-articular passage, avoid hardware problems, and facilitate possible revision surgery; and (4) intraoperative use of a suture tensioner to achieve satisfactory compression of the graft and increase its consolidation.

Analysis of the coracoid morphology with multiplanar 2D CT and its effects on the graft size in the Latarjet procedure

PURPOSE

In this study, we aimed to reveal the individual differences regarding the size of the coracoid and their effects on the classical and modified Latarjet procedures.

METHODS

Computed tomography images of 120 patients (mean age: 41.18 ± 12.01 years) without shoulder complaints or shoulder instability were evaluated retrospectively. The glenoid width, the surgical graft length, and the coracoid total length, width, and thickness were measured using the multiplanar reconstruction method on the Sectra Picture Archiving and Communications System (PACS) system. Age, gender, side, the dominant hand, and the height of the patients were recorded and the correlations between them were investigated. On the created hypothetical model, the current size of the coracoid was evaluated to determine what size of glenoid defects it could repair by employing the classical and the modified Latarjet techniques.

RESULTS

There was no significant difference between the right-hand-dominant group and the left-hand-dominant group in terms of coracoid measurement results (p > 0.05). Again, there was no statistically significant difference between the right and the left side regarding the coracoid size (p > 0.05). A positive correlation could be detected only between age and the coracoid width and thickness (p < 0.05). A positive correlation was also found between the glenoid width and the coracoid width and thickness in both shoulders (p < 0.001). Coracoid thickness could fill in the defects that amounted to 40% of the glenoid width, while the coracoid width could fill in for the defects that were 50% of the glenoid width in both genders.

CONCLUSION

Our study showed that hand dominance and side were not effective on the coracoid dimensions. In addition, it has been shown that the coracoid dimensions did not have a significant effect in the choice of Latarjet technique in terms of defect repair and that repair rates of up to 40% could be achieved in glenoid defects with both techniques.

Utility of Allograft Talus as a Source for Grafting of Concurrent Humeral and Glenoid Defects Associated With Anterior Glenohumeral Instability: An Anthropometric Analysis

PURPOSE

To compare morphologic data of the talus using magnetic resonance images with previously reported values of the humeral head and the glenoid as a potential graft source for both the humeral head as well as glenoid reconstruction in the setting of concomitant glenoid and humeral head defects.

METHODS

All magnetic resonance images of the ankle were reviewed for assessment of the morphology and variation of the talus among individuals. Patients with post-traumatic, osteoarthritic, or surgical changes to the distal tibia about the mid- or hind- foot, or patients with incomplete medical records were excluded. Radiographic parameters that were measured included the maximum vertical height (MVH), the height to the talar neck, the radius of curvature (ROC) of the talar dome, ROC of the subtalar joint, and the maximum medial-to-lateral width of the talar dome. Demographic data also were collected on each individual. Statistical analysis was performed via a linear regression model with backwards elimination to determine which demographic data correlated most strongly with talar anthropometric values.

RESULTS

A total of 82 study patients met inclusion criteria (59 male, 23 female; mean age 40.91 ± 14.69 years). Sex was found have a positive correlation of the following talar dimensions: MVH (P = .039), talar dome ROC (P < .001), and subtalar joint ROC (p = 0.001). Height was the most positive correlation for medial-to-lateral width (P < .001), height to the talar neck (P = .004), and also correlate for MVH (P = .004). Body mass index was found to have multicollinearity and was therefore not used as a variable.

CONCLUSIONS

Allograft talus appears to be a viable graft, as demonstrated in this anthropometric study for both reconstruction of the glenoid and humeral head when cases of bipolar glenohumeral bone loss are present.

CLINICAL RELEVANCE

This study aims to further evaluate potential allograft donor sites for bipolar lesions.

Use of allograft to reconstruct anterior bony glenoid defect in chronic glenohumeral instability: a systematic review

INTRODUCTION

Bone-block procedures are well-established in anterior chronic shoulder instability treatment. Autograft with the coracoid process (Bristow-Latarjet procedures) and iliac crest (Eden-Hybbinette) are the most frequent source of bone but the use of allograft is also possible. The objective of this review is to assess clinical and radiographic outcomes after bony allograft reconstruction in anterior glenohumeral instability.

MATERIAL AND METHODS

Medline, Cochrane, Embase databases were searched for studies reporting on bone allograft reconstruction in anterior glenohumeral instability with glenoid defect. We conducted a systematic review of studies with all levels of evidence reporting on clinical or radiological outcomes or both.

LEVEL OF EVIDENCE

IV.

RESULTS

Ten studies met the inclusion criteria for the review; 283 shoulders were included with a mean age of 26 years (17-63) and mean follow-up of 34 months (4-168). Glenoid reconstruction was performed using bone from different source: femoral head (1 study), distal tibia allograft (5 studies), and iliac crest (4 studies). Allografts were fresh in 4 studies, demineralized in 2 studies, and freeze-dried after sterilization in 1 study. All scores performed in the different studies increased between pre-operative and post-operative evaluations (mean + 36.8 points for the ASES). Global rate of recurrence was 3.9% (11 patients) (0-11%), comprising 6 cases of dislocation (2.1%) and 5 subluxations (1.8%). Allograft healing occurred in 93.5% of cases.

CONCLUSIONS

This systematic review data suggest that allograft reconstructions in anterior glenohumeral instability could be a viable alternative to similar reconstructions with autografts and provide close clinical/radiological outcomes, at short and mid-term follow-up. Prospective randomized studies are needed to confirm these results.

Imaging of shoulder instability

The shoulder enjoys the widest range of motion of all the joints in the human body, therefore requires a delicate balance between stability and motility. The glenohumeral joint is inclined to fall into two main instability categories: macro and micro. Macroinstability can be traumatic or atraumatic, with anterior or posterior dislocation of the humeral head. Microinstability falls within the broader section of acquired instability in overstressed shoulder caused by repeated joint stress. Anterior traumatic instability is the most frequent entity and a relatively common injury in young and athletic population. While shoulder instability is a clinical diagnosis, imaging impacts the patient management by detailing the extent of injury, such as capsulo-labral-ligamentous tears, fracture, and/or dislocation, describing the predisposing anatomic conditions and guide the therapetic choice. The aim of this comprehensive review is to cover the imaging findings of shoulder instability by different imaging techniques.

Editorial Commentary: Classic and Congruent-Arc Latarjet Techniques Are Equally Safe and Effective Procedures, so Choose Whichever Technique Works Best in Your Hands for Your Patients

The classic and congruent-arc Latarjet techniques are equally safe and effective in restoring glenohumeral stability, even when performed as a revision of a failed stabilization. The classic technique provides a broader contact area for healing and facilitates and improves screw fixation. The congruent-arc technique theoretically optimizes glenohumeral contact forces because of the matched radius of curvature, provides better restoration of glenoid depth, and restores larger glenoid defects. However, rotating the coracoid graft for the congruent-arc technique eliminates the possibility of imbricating the coracoacromial ligament stump to the capsule. Surgeons have little reason to change from one technique to the other; both techniques result in successful outcomes.

Revision of failed Latarjet with the Eden-Hybinette surgical technique

INTRODUCTION

The outcomes of the Latarjet procedure for anterior shoulder instability are highly satisfactory although recurrences are possible. Surgical revision is challenging, and often requires an iliac crest bone graft as described by Eden and Hybinette. The aims of our study were to analyze the outcomes of the Eden-Hybinette technique after failed Latarjet procedure, determine the failure and complication rates, and analyze the risk of osteoarthritis. We hypothesized that the Eden-Hybinette technique would yield good outcomes after failed Latarjet procedure.

MATERIAL AND METHODS

Retrospective multicenter study (9 hospitals) by the French Shoulder and Elbow Society (SoFEC) involving 46 patients who underwent revision surgery with an Eden-Hybinette procedure after failed Latarjet stabilization. The patients had a minimum follow-up of 1year and the outcomes were evaluated based on the Rowe score, Walch-Duplay score and radiographs.

RESULTS

The mean age at the final assessment was 32years. The mean follow-up was 38 months and 86% of patients had a stable shoulder with an overall satisfaction rate of 80%. Postoperatively, the Rowe score averaged 76/100 and the Walch-Duplay score averaged 68/100; 60% of patients had resumed their sports participation. Return to sport was statistically correlated with age (p=0.0001), osteoarthritis (p=0.05) and time elapsed between the two surgical procedures (p=0.0001). The Rowe score was statistically correlated with osteoarthritis (p=0.01).

DISCUSSION/CONCLUSION

Our study is one of the largest on the Eden-Hybinette procedure for recurrent anterior shoulder instability. The outcomes at 3years' follow-up were satisfactory in 80% of patients and 86% had stable shoulders. The osteoarthritis rate was low (11%), although the follow-up period was relatively short.

LEVEL OF EVIDENCE

IV, non-randomized multicenter retrospective study.

Scapular Spine Dimensions and Suitability as a Glenoid Bone Graft Donor Site

BACKGROUND

Current structural bone graft options used for glenoid augmentation in glenohumeral instability have known drawbacks. The scapular spine may be a possible alternative graft choice, but its dimensions and anatomy are not fully reported.

HYPOTHESIS

The scapular spine's harvestable graft dimensions will be similar to harvestable dimensions of the coracoid and iliac crest.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The scapular spine, coracoid, and iliac crest dimensions were recorded and compared bilaterally in 50 patients with 3-dimensional computed tomography imaging. The portion of the scapular spine with the largest harvestable dimensions was quantified and its location defined. Measurements were independently taken by 2 investigators and averaged for the final result.

RESULTS

The scapular spine has 81.5 mm of harvestable length and a "flare" located approximately 49.6 mm lateral to the medial scapular border, where the widest harvestable cross section is located (mean harvestable dimensions: 10.9-mm height, 11.5-mm width). Mean coracoid dimensions were 24-mm length, 14.2-mm height, and 10.6-mm width. Mean iliac crest width was 14.7 mm. In sum, 96% of scapular spines, 85% of coracoids, and 100% of iliac crests exceeded minimum dimensions of 8 mm × 8 mm × 20 mm. The coronal radius of curvature of the glenoid was significantly different from the corresponding plane of all measured structures.

CONCLUSION/CLINICAL RELEVANCE

The scapular spine has dimensions similar to the coracoid and iliac crest in the majority of patients and is therefore appropriate for further investigation as a potential graft choice in glenohumeral instability. A harvest location 49.6 mm lateral to the medial scapular border will provide the largest cross-sectional graft while avoiding the acromial base.

Bony Reconstruction of the Anterior Glenoid Rim

Recurrent anterior shoulder instability is associated with glenohumeral bone loss. Glenoid deficiency compromises the concavity-compression mechanism. Medial Hill-Sachs lesions can result in an off-track humeral position. Anterior glenoid reconstruction or augmentation prevents recurrence by addressing the pathomechanics. In Bristow and Latarjet procedures, the coracoid process is harvested for conjoint tendon transfer, capsular reinforcement, and glenoid rim restoration. Complications and the nonanatomic nature of the procedure have spurred research on graft sources. The iliac crest is preferred for autogenous structural grafts. Tricortical, bicortical, and J-bone grafts have shown promising results despite the historical association of Eden-Hybinette procedures with early degenerative joint disease. Allogeneic osteochondral grafts may minimize the risk of arthropathy and donor site morbidity. Tibial plafond and glenoid allografts more closely match the native glenoid geometry and restore the articular chondral environment, compared with conventional grafts. Graft availability, cost, risk of disease transmission, and low chondrocyte viability have slowed the acceptance of osteochondral allografts.

The Eden-Hybbinette procedure is one hundred years old! A historical view of the concept and its evolutions

INTRODUCTION

One hundred years ago, before Bankart, Latarjet or Bristow, Eden and Hybbinette developed a procedure to treat anterior shoulder instability and currently, this eponymous term is known by every shoulder surgeon. The purpose of this review is to summarise the historical "Eden-Hybbinette" procedure and its evolutions during the last century and discuss results.

METHOD

On the centenary of the first publication on the "Eden-Hybbinette procedure", a search was conducted on Medline, Google Scholar and in the grey literature, to find its initial concept and description, and the evolutions.

RESULTS

The initial procedure was based on the concepts of glenoid bony augmentation (anatomic reconstruction with an autograft from the tibia) and capsulorrhaphy. The main evolutionary themes identified were the origin of the graft (autograft with iliac crest, allograft), graft positioning and fixation (no fixation device, screws), and the surgical approach (split of the subscapularis tendon in open surgery, arthroscopy). Studies with long-term follow-up exhibited good results, considered similar as those with other classic bone-block procedures. Development of osteoarthritis during the following years after the procedure is not usual and not related to the graft unless if there is articular protrusion.

CONCLUSION

The Eden-Hybbinette procedure is one of the oldest surgical interventions still commonly used for chronic anterior shoulder instability. The changes to the procedure over the last 100 years allow it to remain a contemporary solution for both primary surgery and revision cases.

[Bony Bankart lesions and glenoid defects : From refixation techniques to bony augmentation]

Rim defects of the anterior glenoid cavity are a main reason for residual shoulder instability after traumatic dislocation of the shoulder. These defects can be the result of a glenoid rim fracture or chronic glenoid erosion after repeated shoulder dislocations. Treatment concepts for these entities are entirely different. While in the acute fracture situation glenoid rim fractures can be treated operatively or non-operatively, augmentation of the anterior glenoid for stabilization of the shoulder should be considered if the defect exceeds 15-25% of the anterior glenoid. The purpose of this article is to summarize the diagnostics and indications for treatment of glenoid rim fractures. Radiological assessment and options for augmentation are reviewed for both acute fractures as well as chronic instability following an anterior glenoid rim defect.

Management of Glenoid Bone Loss with Anterior Shoulder Instability: Indications and Outcomes

PURPOSE OF REVIEW

Glenoid Bone Loss is a commonly encountered problem in anterior shoulder instability. In this article, we review current techniques for diagnosis, indications and management of glenoid bone loss.

RECENT FINDINGS

Multiple bone grafting techniques are available depending on the glenoid defect size including the coracoid, distal clavicle, iliac crest, and allograft distal tibia. Advancement in imaging methods allows for more accurate quantification of bone loss. Indications and techniques are continuing to evolve, and emerging evidence suggests that smaller degrees of bone loss "subcritical" may be best treated with bone grafting. Future directions for innovation and investigation include improved arthroscopic techniques and a refinement of indications for the type of bone grafts and when to indicate a patient of arthroscopic repair versus glenoid bone grafting for smaller degrees of bone loss to ensure successful outcome.

Editorial Commentary: Whatever You Do: Anatomic Restoration of the Biconcave Glenoid Morphometry for Bone Defects in Patients With Anterior Shoulder Instability Is Nearly Impossible

There are many bone block procedures described to treat glenoid bone defects in anterior shoulder instability and most of these techniques apparently result in anatomic reconstruction. However, anatomic restoration of the biconcave glenoid morphometry for bone defects in patients with anterior shoulder instability is nearly impossible.

Restoration of Articular Geometry Using Current Graft Options for Large Glenoid Bone Defects in Anterior Shoulder Instability

PURPOSE

The purpose of this cadaveric study was to compare standard and modified coracoid transfer procedures, bicortical and tricortical iliac crest autografts, and tibial plafond and glenoid allografts with respect to glenoid surface curvature restoration.

METHODS

Computed tomography scans of 8 cadaveric shoulders were acquired in 9 conditions: (1) intact, (2) 25% width defect, (3) classic Latarjet, (4) modified congruent-arc Latarjet, (5) tricortical iliac crest inner table, (6) outer table, (7) bicortical iliac crest, (8) distal tibia, and (9) glenoid allograft. Outcome measures included articular surface area, width, depth, axial and coronal radius of curvature, and subchondral articular step-off, analyzed in bone and soft-tissue window.

RESULTS

Reconstruction of the articular surface area was optimal with the glenoid allograft (99.4%), classic Latarjet (97.4%), and iliac crest bicortical graft (93.2%). Depth was best restored by the congruent-arc Latarjet (101.0%), tibial (98.9%), and glenoid (95.3%) allografts. Axial curvature was closely matched by the glenoid allograft (97.5%), classic Latarjet (108.7%), and iliac bicortical graft (91.2%). Coronal curvature was most accurately restored by the glenoid allograft (102.6%), the tibial allograft (115.0%), and the classic Latarjet (55.9%). The articular step-off was smallest using the glenoid allograft.

CONCLUSIONS

Overall, glenoid allografts most accurately restored articular geometry. Alternative grafts provided restoration of some parameters but not others. Classic Latarjet performed well in axial and coronal curvature on average but exhibited large variability. Tibial allograft produced the poorest results in axial curvature, despite excellent coronal curvature reconstruction. The congruent-arc Latarjet did not restore the axial curvature accurately and overcorrected coronal curvature. Graft geometry must be weighed against availability, morbidity, and the role of additional stabilizers.

CLINICAL RELEVANCE

Accurate graft morphology may help prevent postoperative osteoarthritis. Grafts differ significantly regarding geometric parameters. The findings of this study will help surgeons select the most appropriate graft for glenoid reconstruction.

Anatomic and Biomechanical Comparison of the Classic and Congruent-Arc Techniques of the Latarjet Procedure

BACKGROUND

The Latarjet procedure is commonly performed using either the classic or the congruent-arc technique. Each technique has potential clinical advantages and disadvantages. However, data on the anatomic and biomechanical effects, benefits, and limitations of each technique are limited. Hypothesis/Purpose: To compare the anatomy and biomechanical fixation strength (failure load) between the 2 techniques. It was hypothesized that the classic technique would have superior initial fixation when compared with the congruent-arc technique and that this would be affected by sex and coracoid size.

STUDY DESIGN

Controlled laboratory study.

METHODS

A biomechanical cadaver study was performed with 20 pairs of male and female shoulders. One of each pair of shoulders was randomly assigned to receive the classic or congruent-arc technique. Coracoid and glenoid anatomic measurements were collected before biomechanical testing. A tensile force was applied through the conjoined tendon to replicate forces experienced by the coracoid graft in the early postoperative period, and the failure load was determined for each specimen.

RESULTS

The mean ± SD surface area available for fixation was 263 ± 63 mm² in the classic technique compared with 177 ± 63 mm² in the congruent-arc group ( P < .001). 36% of the glenoid width was recreated in the classic group and 50% in the congruent-arc group ( P < .001). The congruent-arc technique resulted in a significantly lower ( P = .005) mean failure load (239 ± 91 N) compared with the classic technique (303 ± 114 N). Failure load was significantly higher in males ( P = .037); male specimens had a mean failure load of 344 ± 122 N for the classic technique and 289 ± 73 N for the congruent-arc technique, and females had a mean failure load of 266 ± 98 N and 194 ± 84 N, respectively.

CONCLUSION

In this biomechanical model, the classic technique of the Latarjet procedure provided a greater surface area for healing to the glenoid and superior initial fixation when compared with the congruent-arc technique. The congruent-arc technique allowed restoration of a larger glenoid defect.

CLINICAL RELEVANCE

The classic and congruent-arc techniques of coracoid transfer have anatomic and biomechanical advantages and disadvantages that should be considered when choosing between the 2 techniques.

Distal tibia allograft for glenohumeral instability: does radius of curvature match?

BACKGROUND

A distal tibia osteochondral allograft is a potential graft option for glenoid reconstruction because the distal tibia may have a similar radius of curvature (ROC) as the glenoid. This study evaluated ROC mismatch as measured on computed tomography (CT) scans between the glenoid, distal tibia, and humeral head.

METHODS

Bilateral CT images were formatted for 10 decedents from the Office of the Medical Investigator database, giving 20 specimens per anatomic location. The ROCs of the glenoid, distal tibia, and humeral head were measured. A statistical model was generated to assess ROC mismatch of randomly paired distal tibias and glenoids.

RESULTS

The mean ± standard deviation ROC was 2.9 ± 0.25 cm for the glenoid, 2.3 ± 0.21 cm for the distal tibia, and 2.5 ± 0.12 cm for the humeral head. No differences were found in laterality, intraobserver, or interobserver measurements. The least-squares difference in the ROC between the glenoid and tibia was 0.57 cm, glenoid and humerus was 0.40 cm, and humerus and tibia was 0.17 cm. Only 22% of randomly paired distal tibias and glenoids had a difference in ROC of 0.3 cm or less.

CONCLUSION

CT measurement of the ROC of the glenoid, distal tibia, and humeral head is reliable and reproducible. The probability of obtaining a random distal tibia allograft with a similar ROC to the glenoid is low. Obtaining ROC measurements of the injured glenoid and the distal tibia allograft specimen before use for glenoid reconstruction may be useful.

Comparison of 3-Dimensional Computed Tomography-Based Measurement of Glenoid Bone Loss With Arthroscopic Defect Size Estimation in Patients With Anterior Shoulder Instability

PURPOSE

The purpose of this study was to compare four 3-dimensional (3D) computed tomography (CT) methods of measuring glenoid bone loss with the arthroscopic estimation of glenoid bone loss.

METHODS

Twenty patients with recurrent anterior shoulder instability underwent bilateral shoulder CT scans and were found to have glenoid bone loss. Arthroscopic estimation of glenoid bone loss was performed in all patients. Three-dimensional CT reconstruction was performed on the CT scans of each patient. The glenoid bone loss of each patient was measured using the surface area, Pico, ratio, and anteroposterior distance-from-bare area methods. The mean percent loss calculated with each method was compared with arthroscopy to determine the reliability of arthroscopy in the measurement of glenoid bone loss.

RESULTS

The mean percent bone loss calculated with arthroscopic estimation, surface area, Pico, ratio, and anteroposterior distance-from-bare area methods was 18.13% ± 11.81%, 12.15% ± 8.50% (P = .005), 12.77% ± 8.17% (P = .002), 9.50% ± 8.74% (P < .001), and 12.44% ± 10.68% (P = .001), respectively. Repeated-measures analysis of variance showed that the 3D CT methods and arthroscopy were significantly different (F4,76 = 13.168, P = .02). The estimate using arthroscopy is 55% greater than the average of the 3D CT methods.

CONCLUSIONS

Our findings suggest that arthroscopy significantly overestimates glenoid bone loss compared with CT and call into question its validity as a method of measurement. A more internally consistent and accurate method for the measurement of glenoid bone loss is necessary to appropriately diagnose and treat shoulder instability.

LEVEL OF EVIDENCE

Level IV, case series.