The role of bone in glenohumeral stability

Capsule elongation occurs after first time shoulder dislocation A biomechanical in-vitro investigation on human cadaveric specimen

Purpose

As capsule elongation is assumed to weaken the static stability of the shoulder joint, the purpose of this biomechanical study was to demonstrate that capsule elongation occurs immediately after a first-time shoulder dislocation and not just after recurrent dislocation events. We hypothesize an increment in joint clearance due to joint capsule elongation after a first-time dislocation.

Methods

An experimental in-vitro study was conducted on 6 paired fresh frozen human shoulders (4 females; 2 males; 12 specimen) with a mean age of 80 (Range 67-89) years. The shoulder joint with the articular capsule was exposed and an inferior static tension force of 2.5 N was applied to the humerus prior to dislocation. Next, the humeral head was dislocated and was then immediately reduced back into the start position. The joint gap as well as joint capsule deformation was assessed using optical techniques.

Results

The radiographic joint gap increased from 13.7 ± 6.9 mm (prior to dislocation) to 18.1 ± 6.5 mm (post dislocation) (p < .001). The increase in joint clearance was 4.4 mm. The joint capsule elongated from 5.9 ± 0.005 % (prior to dislocation) to 9.4 ± 0.007 % (post dislocation) (p < .001). The mean increase in joint capsule elongation was 3.5 %.

Conclusions

Capsule elongation was observed immediately after a simulated first-time shoulder dislocation in an in-vitro model of elderly human cadavers. It might therefore not only be a phenomenon of recurrent dislocation events.

Surgical considerations for glenoid bone loss in anterior glenohumeral instability: a narrative review

PURPOSE

Treatment algorithms may consider many factors like glenoid and humeral bone loss, or scores such as the instability severity index score (ISIS). As most studies only evaluate a part of these factors, there is still no evidence-based consensus estalished. Our study aims to summarize the surgical options for treatment of glenoid bone loss (GBL) in anterior shoulder instability.

METHODS

Based on the current available literature, surgical options including Bankart repair and glenoid bone augmentation should be considered while taking into consideration the degree of bone loss which has been divided into < 10%, 10-20% and > 20%.

RESULTS

There are many new techniques evolving including arthroscopic anatomic glenoid reconstruction with bone blocks.

CONCLUSION

Future long-term outcome studies and randomized controlled trials comparing established techniques will be needed for new evidence-based treatment algorithms.

Influence of body mass index on severity of rotator cuff tears

BACKGROUND

Research on the relationship between obesity and rotator cuff tears (RCTs) has been limited to the impact of obesity on the results of arthroscopic repair of RCTs; thus, a need for rigorous research controlling for other factors affecting RCTs is warranted, especially to better understand the impact of body mass index (BMI) on RCT severity.

METHODS

A retrospective study of admission records contained in electronic medical records pertaining to patients who were admitted for RCT repair on 1 shoulder between January 2018 and July 2022 was conducted. In total, 386 patients were included. In accordance with guidance regarding obesity from Taiwan's Ministry of Health and Welfare, patients were divided into three groups: underweight or normal weight (BMI <24.0 kg/m2), overweight (BMI 24.0-26.9 kg/m2), or obese (BMI ≥27.0 kg/m2). Magnetic resonance imaging was used to assess RCT severity in terms of four parameters: Patte stage (PS), fatty infiltration (FI), anteroposterior tear size (AP), and retraction size. Multinomial logistic regression analysis was performed on PS and FI grade data, and multiple linear regression analysis was performed on AP tear size and retraction size in order to analyze impact.

RESULTS

Our results revealed that the average age of the 386 patients was 63.41 years (SD = 9.29) and the mean BMI was 25.88 (SD = 3.72) kg/m2. We found significant differences in PS (P = .003), FI (P < .001), retraction size (P = .001), and AP tear size (P = .001) among patients who were underweight or normal weight, overweight, and obese. After controlling for other risk factors, including age, gender, RCT-prone occupation, duration of shoulder pain prior to surgery, history of shoulder injury, and tobacco use, we found that obese patients had higher severity levels in PS (B = 1.21, OR = 3.36, P = .029), FI (B = 1.38, OR = 3.96, P < .001), retraction size (β = 0.18, P = .001), and AP tear size (β = 0.18, P = .001) compared to underweight or normal weight patients.

CONCLUSIONS

Our study demonstrates that a correlation exists between BMI-measured obesity and RCT severity. We therefore suggest that adults control their weight given that maintaining a healthy weight is highly associated with better shoulder health.

Biomechanical and neuromuscular characteristics in patients with traumatic anterior shoulder instability undergoing arthroscopic Bankart repair: a clinical prospective cohort study protocol

INTRODUCTION

Traumatic shoulder dislocation is a common shoulder injury, especially among the young and active population. More than 95% of dislocations are anterior, in which the humeral head is forced beyond the anterior glenoid rim. The injury leads to increased joint laxity and recurrence rates are high. There is evidence that the shoulder biomechanics and neuromuscular control change following dislocation, but the existing literature is scarce, and it remains to be established if and how these parameters are useful in the clinical setting. The aim of this exploratory prospective cohort study is to investigate biomechanical and neuromuscular outcomes in patients with traumatic anterior shoulder instability undergoing arthroscopic Bankart repair, to test the hypothesis that examinations of these characteristics are applicable in the clinical setting to assess shoulder instability.

METHODS AND ANALYSIS

This is a prospective multicentre cohort study with repeated measures of 30 patients undergoing arthroscopic Bankart repair. With carefully selected and completely non-invasive examination methods, we will investigate biomechanical and neuromuscular outcomes in the affected shoulders once presurgically and twice post surgically at 6 and 12 months. Patients' contralateral shoulders are investigated once to establish a preinjury level.

ETHICS AND DISSEMINATION

The study was approved by the Capital Region Ethics Committee (journal-no: H-21027799) and the Capital Region Knowledge Center for Data Reviews (journal-no: P-2021-842) before patient recruitment began. The study results will be published in international peer-reviewed journals, online and in other relevant media, presented at medical conventions and disseminated to clinicians and patients as appropriate.

TRIAL REGISTRATION NUMBER

NCT05250388.

Comparative Analysis of Various Rotator Cuff Stretching Techniques: Efficacy and Recommendations for Gym Enthusiasts

Shoulder pain is a common complaint among gym-going individuals, particularly those engaged in upper limb workouts. The rotator cuff, comprising four muscles, plays a crucial role in stabilizing the shoulder joint during movements and supporting its mobility. Imbalances or weaknesses in these muscles can lead to shoulder injuries, affecting performance and overall well-being. The main aim of this review is to explore the benefit of one of the approaches in preventing shoulder pain and improving performance among gym-going individuals. Specific rotator cuff stretching exercises target the entire shoulder complex to enhance the mobility, control, and stabilization of the joint. The dynamic warm-up routine will actively engage the relevant muscles in various planes of motion, promoting the increased range of motion and reduced inflammation. Ultimately, the results from this review can serve as important knowledge for gym-going individuals, trainers, and fitness enthusiasts, guiding them in incorporating evidence-based warm-up strategies to optimize their workouts. Empowering individuals to take proactive measures in caring for their shoulder health can lead to improved overall performance and a better training experience in the gym.

How does dynamic arthroscopic tracking compare with radiologic glenoid track for identification of on- and off-track lesions in anterior shoulder instability?

BACKGROUND

Current treatment paradigms for anterior shoulder instability are based on radiologic measurements of glenohumeral bone defects, and mathematical calculation of the glenoid track (GT) is used to classify lesions into on-track and off-track morphology. However, radiologic measurements have shown high variability, and GT widths under dynamic conditions have been reported to be significantly smaller than those under static radiologic conditions. The purpose of this study was to assess the reliability, reproducibility, and diagnostic validity of dynamic arthroscopic standardized tracking (DAST) in comparison to the gold-standard radiologic track measurement method for the identification of on- and off-track bony lesions in patients with anteroinferior shoulder instability.

METHODS

Between January 2018 and August 2022, 114 patients with traumatic anterior shoulder instability were evaluated using 3-T magnetic resonance imaging or computed tomography scans; glenoid bone loss, Hill-Sachs interval, GT, and Hill-Sachs occupancy ratio (HSO) were measured, and defects were classified as on-track or off-track defects and peripheral-track defects (based on HSO percentage) by 2 independent researchers. During arthroscopy, a standardized method (DAST method) was used by 2 independent observers to classify defects into on-track defects (central and peripheral) and off-track defects. Interobserver reliability of the DAST and radiologic methods was calculated using the κ statistic and reported as percentage agreement. Diagnostic validity (sensitivity, specificity, positive predictive value, and negative predictive value) of the DAST method was calculated using the radiologic track (HSO percentage) as the gold standard.

RESULTS

The radiologically measured mean glenoid bone loss percentage, Hill-Sachs interval, and HSO in off-track lesions were lower with the arthroscopic method (DAST) as compared with the radiologic method. The DAST method showed nearly perfect agreement between the 2 observers for the on-track/off-track classification (κ = 0.96, P < .001) and the on-track central or peripheral /off-track classification (κ = 0.88, P < .001). The radiologic method showed greater interobserver variability (κ = 0.31 and κ = 0.24, respectively) with only fair agreement for both classifications. Inter-method agreement varied between 71% and 79% (95% confidence interval, 62%-86%) between the 2 observers, and reliability was assessed as slight (κ = 0.16) to fair (κ = 0.38). Overall, for identification of an off-track lesion, the DAST method showed maximum specificity (81% and 78%) when radiologic peripheral-track lesions (HSO percentage of 75%-100%) were considered off-track and showed maximum sensitivity when arthroscopic peripheral-track lesions were classified as off-track.

CONCLUSION

Although inter-method agreement was low, a standardized arthroscopic tracking method (DAST method) showed superior interobserver agreement and reliability for lesion classification in comparison to the radiologic track method. Incorporating DAST into current algorithms may help reduce variability in surgical decision making.

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.

Comparison of Glenohumeral Bone Morphology Between Patients With Versus Without Anterior Shoulder Instability

Background

The stability of the glenohumeral joint is associated with anatomic characteristics including bony structures and soft tissues.

Purpose

To compare the differences in specific bony glenohumeral geometries between shoulders with anterior shoulder instability (ASI), unaffected contralateral shoulders, and healthy control shoulders.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Shoulder computed tomography (CT) scans of 36 patients with ASI and 36 matched healthy controls were retrieved and 3-dimensionally reconstructed. We measured the glenoid radius of curvature (GROC) in the anterior-posterior (AP) and superior-inferior directions, humeral head radius of curvature (HROC) in the AP direction, conformity index, glenoid height, glenoid width, glenoid index, stability angle, glenoid version, and glenoid depth. The differences between the groups were statistically calculated. CT scans of the unaffected contralateral shoulders from 21 of the ASI patients were also collected to identify the consistency of the bony structures in bilateral shoulders.

Results

Patients with ASI had greater GROC in the AP direction (P < .001), HROC in the AP direction (P = .002), glenoid height (P = .005), and glenoid index (P < .001) and smaller conformity index (P < .001), glenoid width (P = .002), stability angle (P < .001), and glenoid depth (P < .001). In addition, the glenoid of the ASI patients was more anteverted compared with that of controls (P = .001). There was no statistical difference in half the measurements between the bilateral shoulder joints in patients with ASI.

Conclusion

In this study, glenohumeral geometric differences were found between ASI patients and healthy control participants. Glenoid curvature and conformity index, based on bilateral comparisons of affected and contralateral shoulders, appear inherent and may predict ASI risk.

Anterior-posterior glenohumeral translation in shoulders with traumatic anterior instability: a systematic review of the literature

Background

Reports of glenohumeral translation in shoulders with traumatic anterior instability have been presented. The aim of this systematic review was to investigate anterior-posterior translation in shoulders with traumatic anterior instability.

Methods

This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies including patients aged ≥15 years with previous traumatic anterior shoulder dislocation or subluxation were included. The outcome was anterior-posterior glenohumeral translation. A search of PubMed, Embase, and Cochrane library was performed on July 17, 2022. Two reviewers individually screened titles and abstracts, reviewed full text, extracted data, and performed quality assessment.

Results

Twenty studies (582 unstable shoulders in total) of varying quality were included. There was a lack of standardization and unity across studies. Radiography, ultrasound, computed tomography, magnetic resonance imaging, motion tracking, instrumentation, and manual testing were used to assess the glenohumeral translation. The glenohumeral translation in unstable shoulders ranged from 0.0 ± 0.8 mm to 11.6 ± 3.7 mm, as measured during various motion tasks, arm positions, and application of external force. The glenohumeral translation was larger or more anteriorly directed in unstable shoulders than in stable when contralateral healthy shoulders or a healthy control group were included in the studies. Several studies found that the humeral head was more anteriorly located on the glenoid in the unstable shoulders.

Conclusion

This systematic review provides an overview of the current literature on glenohumeral translation in traumatic anterior shoulder instability. It was not able to identify a threshold for abnormal translation in unstable shoulders, due to the heterogeneity of data. The review supports that not only the range of translation but also the direction hereof as well as the location of the humeral head on the glenoid seem to be part of the pathophysiology. Technical development and increased attention to research methodology in recent years may provide more knowledge and clarity on this topic in the future.

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.

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.

Arthroscopic Distal Clavicle Bone Block Technique for Anteroinferior Instability With Critical Bone Loss

Arthroscopic distal clavicle autograft represents a locally available source of autograft for bone block augmentation in patients with anterior shoulder instability with glenoid bone loss. Anatomic and biomechanical studies have supported distal clavicle autograft use as comparable to coracoid graft with regard to restoration of glenoid articular surface, with the theoretical advantage of minimizing complications associated with coracoid transfer procedures, such as neurologic injury and coracoid fracture. The current technique describes a modification of those previously described, including a mini-open approach for distal clavicle autograft harvest, orientation of the distal clavicle with the medial clavicle graft against the glenoid (congruent arc), an all-arthroscopic technique of graft passage, and graft placement and fixation using specialized drill guides and four suture buttons to reproducibly place and secure the graft with final capsulolabral advancement over the graft to render it extra-articular.

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.

Effect of shape and size of supraspinatus tears on rotator cuff strain distribution: an in vitro study

BACKGROUND

The impact of the size and shape of a supraspinatus tear on the strain of the intact rotator cuff and the kinematics of the shoulder is still unknown. This, however, can be relevant when deciding whether surgical reconstruction is required to prevent an increase in a tendon defect. In this study, the effect of tear width and shape on rotator cuff strain and glenohumeral kinematics was evaluated during active abduction.

METHODS

Twelve fresh-frozen cadaveric shoulders with intact rotator cuffs were used in this study. We created 50% and 100% wide (full-thickness) crescent-shaped (CS) tears (n = 6) and reverse L-shaped (rLS) tears (n = 6) in the supraspinatus tendon and measured strain and kinematics during active humeral elevation until 30°.

RESULTS

Both tear shapes and sizes led to an increase in internal rotation, supraspinatus loading force, and superior translation of the humerus. For the 100% wide tear size, anterior translation was observed in the CS tear group, whereas in the rLS tear group, this translation occurred mainly in the posterior direction. Strain was higher in the infraspinatus during the first 25° of abduction in comparison with the supraspinatus tendon in both tear shape groups. An analysis of the anterior and posterior tear borders showed a higher strain concentration on the same side of the tear in the CS tear group with 50% and 100% wide tears.

CONCLUSIONS

The influence of different tear shapes on translation in the anterior-posterior direction was evident as both CS and rLS tears led to an oppositely directed translation of the humeral head. The strain analysis showed a stress-shielding effect of the infraspinatus at the beginning of abduction. Therefore, special attention must be paid to correctly identify the tear extension and adequately reconstruct the rotator cuff footprint. Moreover, the constant location of maximum strain in the CS tear group may lead to an earlier progression than in the rLS tear group.

Anterior glenoid rim erosion in the early stage after arthroscopic Bankart repair affects postoperative recurrence

Background

Recent studies reported that anterior glenoid rim erosion can occur in the early period after arthroscopic Bankart repair (ABR) for traumatic anterior shoulder instability. However, it is unknown whether such erosion is a risk factor for postoperative recurrence. This study evaluated risk factors for postoperative recurrence after ABR, specifically aiming to elucidate whether reduction of postoperative glenoid width due to anterior glenoid rim erosion is one of such factors.

Methods

A total of 220 shoulders that underwent ABR alone between 2013 and 2020 were retrospectively investigated. Patient age at surgery, whether the patient was a collision/contact athlete, anchor placement, preoperative glenoid bone defect (%), localization of the Hill-Sachs lesion, and change of glenoid width (%) in the 6 months after surgery were investigated for their statistical relation to recurrence by univariate and multiple logistic regression analysis.

Results

Postoperative recurrence occurred in 32 of 220 shoulders (14.5%). In univariate analysis, being a collision/contact athlete was the only variable with a significant effect on recurrence (odds ratio [OR], 2.555; 95% confidence interval [CI], 1.123-5.814; P = .03). Change of glenoid width reduction was larger in those with recurrence than without recurrence, but the difference was not statistically significant (-7.0 ± 6.6% vs. -5.0 ± 9.3%; P = .14). However, in multivariate logistic analysis, preoperative glenoid bone defect (%) (adjusted unit OR, 1.076; 95% CI, 1.018-1.137; P = .010) and postoperative change of glenoid width (%) (adjusted unit OR, 0.946; 95% CI, 0.900-0.994; P = .028) had a significant influence on postoperative recurrence.

Conclusion

Glenoid width reduction due to anterior glenoid rim erosion after ABR is a risk factor for recurrence.

Comprehensive management of posterior shoulder instability: diagnosis, indications, and technique for arthroscopic bone block augmentation

Recurrent posterior glenohumeral instability is an entity that demands a high clinical suspicion and a detailed study for a correct approach and treatment. Its classification must consider its biomechanics, whether it is due to functional muscular imbalance or to structural changes, volition, and intentionality.

Due to its varied clinical presentations and different structural alterations, ranging from capsule-labral lesions and bone defects to glenoid dysplasia and retroversion, the different treatment alternatives available have historically had a high incidence of failure.

A detailed radiographic assessment, with both CT and MRI, with a precise assessment of glenoid and humeral bone defects and of glenoid morphology, is mandatory.

Physiotherapy focused on periscapular muscle reeducation and external rotator strengthening is always the first line of treatment. When conservative treatment fails, surgical treatment must be guided by the structural lesions present, ranging from soft tissue repair to posterior bone block techniques to restore or increase the articular surface.

Bone block procedures are indicated in cases of recurrent posterior instability after the failure of conservative treatment or soft tissue techniques, as well as symptomatic demonstrable nonintentional instability, presence of a posterior glenoid defect >10%, increased glenoid retroversion between 10 and 25°, and posterior rim dysplasia. Bone block fixation techniques that avoid screws and metal allow for satisfactory initial clinical results in a safe and reproducible way.

An algorithm for the approach and treatment of recurrent posterior glenohumeral instability is presented, as well as the author’s preferred surgical technique for arthroscopic posterior bone block.

Does native glenoid anatomy predispose to shoulder instability? An MRI analysis

BACKGROUND

It is unclear if native glenohumeral anatomic features predispose young patients to instability and if such anatomic risk factors differ between males and females. The purpose of this study was to compare glenoid and humeral head dimensions between patients with a documented instability event without bone loss to matched controls and to evaluate for sex-based differences across measurements. The authors hypothesized that a smaller glenoid width and glenoid surface area would be significant risk factors for instability, whereas humeral head width would not.

METHODS

A prospectively maintained database was queried for patients aged <21 years who underwent magnetic resonance imaging (MRI) for shoulder instability. Patients with prior shoulder surgery, bony Bankart, or glenoid or humeral bone loss were excluded. Patients were matched by sex and age to control patients who had no history of shoulder instability. Two blinded independent raters measured glenoid height, glenoid width, and humeral head width on sagittal MRI. Glenoid surface area, glenoid index (ratio of glenoid height to width), and glenohumeral mismatch ratio (ratio of humeral head width to glenoid width) were calculated.

RESULTS

A total of 107 instability patients and 107 controls were included (150 males and 64 females). Among the entire cohort, there were no differences in glenoid height, glenoid width, glenoid surface area, humeral head width, or glenoid index between patients with instability and controls. Overall, those with instability had a greater glenohumeral mismatch ratio (P = .029) compared with controls. When stratified by sex, female controls and instability patients showed no differences in any of the glenoid or humerus dimensions. However, males with instability had a smaller glenoid width by 3.5% (P = .017), smaller glenoid surface area by 5.2% (P = .015), and a greater glenohumeral mismatch ratio (P = .027) compared with controls.

CONCLUSION

Compared with controls, males with instability were found to have smaller glenoid width and surface area, and a glenoid width that was proportionally smaller relative to humeral width. In contrast, bony glenohumeral morphology did not appear to be a significant risk factor for instability among females. These sex-based differences suggest that anatomic factors may influence risk of instability for male and female patients differently.

A review of bone grafting techniques for glenoid reconstruction

BACKGROUND

Traumatic anterior shoulder dislocations can cause bony defects of the anterior glenoid rim and are often associated with recurrent shoulder instability. For large glenoid defects of 20-30% without a mobile bony fragment, glenoid reconstruction with bone grafts is often recommended. This review describes two broad categories of glenoid reconstruction procedures found in literature: coracoid transfers involving the Bristow and Latarjet procedures, and free bone grafting techniques.

METHODS

An electronic search of MEDLINE and PubMed was conducted to find original articles that described glenoid reconstruction techniques or modifications to existing techniques.

RESULTS

Coracoid transfers involve the Bristow and Latarjet procedures. Modifications to these procedures such as arthroscopic execution, method of graft attachment and orientation have been described. Free bone grafts have been obtained from the iliac crest, distal tibia, acromion, distal clavicle and femoral condyle.

CONCLUSION

Both coracoid transfers and free bone grafting procedures are options for reconstructing large bony defects of the anterior glenoid rim and have had similar clinical outcomes. Free bone grafts may offer greater flexibility in graft shaping and choice of graft size depending on the bone stock chosen. Novel developments tend towards minimising invasiveness using arthroscopic approaches and examining alternative non-rigid graft fixation techniques.

Combined Double-Pulley Remplissage and Bankart Repair

The use of arthroscopic Bankart repair to treat anterior shoulder instability has become increasingly widespread. However, high rates of recurrent instability within the presence of glenohumeral bony defects, specifically Hill-Sachs lesions, have well documented a key concern regarding the arthroscopic Bankart repair process. Our technique describes the pairing of a remplissage to fill the Hill-Sachs lesion with the Bankart repair, preventing loss in shoulder stiffness and stability. This technique involves a double-pulley-combined remplissage and Bankart repair to maintain a low-failure, minimally invasive procedure.

The Use of Scapular Bone Flaps During Head-and-Neck Reconstruction: Functional, Orthopedic, and Quality of Life Analyses of Flap-Harvest-Related Deficits

ABSTRACT

The authors sought correlations between harvesting of the scapular bone tip free flap used for head-and-neck reconstruction and any shoulder function deficit, particularly at the level of the rotator cuff. The flap permits reconstruction of large and diverse regions of the head and neck, but long-term harvest morbidity has not been investigated extensively. The authors analyzed the clinical records of all patients who underwent head-and-neck reconstructions using free scapular tip flaps in our department over the past 5 years. The inclusion criteria were complete clinical and radiological documentation and follow-up for at least 12 months. Two populations, a surgical and control population, were analyzed. All patients in both populations underwent the simple shoulder test, an internationally validated self-administered test that highlights functional shoulder deficits, and 3 additional tests at orthopedic visits: the external rotation test, Patte test, and external rotation lag sign test. A head-and-neck cancer-specific questionnaire (University of Washington Quality of Life, version 4) was completed by the surgical patients. All statistical analyses were performed using Software IBM SPSS Statistics (IBM Corp., Armonk, NY).A total of 19 patients met the inclusion criteria: 11 males (57.8%) and 8 females (42.2%) of mean age 60.9 years (range 23-75 years). In addition, 20 age-and sex-matched volunteers with no history of shoulder pathology were evaluated in terms of shoulder functionality. The average score on the simple shoulder test was 10.55 in the healthy population versus 8.31 in the study population (P < 0.001); in particular, shoulder strength differed between the groups. Similarly, the orthopedic examinations revealed clinically significant differences between the controls and patients on the Patte test and external rotation lag sign test (both P < 0.001), but not the external rotation test (P > 0.001). The mean University of Washington Quality of Life was 73.39; most patients reported good quality of life (52.6%), followed by very good (15.7%).The free scapular bone tip flap is valuable for reconstruction of head-and-neck defects; the long and reliable vascular pedicle allows rapid patient mobilization. Morbidity was confined to small reductions in shoulder strength and external rotation, which do not affect quality of life.

Greater Tuberosity Fractures Are Not A Continuation Of Hill-Sachs Lesions, But Do They Have A Similar Etiology?

Background

Methods

Results

Conclusion

The Glenolabral Articular Disruption Lesion Is a Biomechanical Risk Factor for Recurrent Shoulder Instability

Purpose

To investigate the biomechanical effect of a glenolabral articular disruption (GLAD) lesion on glenohumeral laxity.

Methods

Human cadaveric glenoids (n = 10) were excised of soft tissue, including the labrum to focus on the biomechanical effects of osteochondral surfaces. Glenohumeral dislocations were performed in a robotic test setup, while displacement forces and three-dimensional morphometric properties were measured. The stability ratio (SR), a biomechanical characteristic for glenohumeral stability, was used as an outcome parameter, as well as the path of least resistance, determined by a hybrid robot displacement. The impacts of chondral and bony defects were analyzed related to the intact glenoid. Statistical comparison of the defect states on SR and the path of least resistance was performed using repeated-measures ANOVA and Tukey’s post hoc test for multiple comparisons (P < .05). The relationship between concavity depth and SR was approximated in a nonlinear regression.

Results

The initial SR of the intact glenoid (28.3 ± 7.8%) decreased significantly by 4.7 ± 3% in case of a chondral defect (P = .002). An additional loss of 3.2 ± 2.3% was provoked by a 20% bony defect (P = .004). The path of least resistance was deflected significantly more inferiorly by a GLAD lesion (2.9 ± 1.8°, P = .002) and even more by a bony defect (2.5 ± 2.9°, P = .002). The nonlinear regression with concavity depth as predictor for the SR resulted in a high correlation coefficient (r = .81).

Conclusions

Chondral integrity is an important contributor to the SR. Chondral defects as present in GLAD lesions may cause increased laxity, influence the humeral track on the glenoid during dislocation, and represent a biomechanical risk factor for a recurrent instability.

Clinical Relevance

Cartilage deficiency corresponding to GLAD lesions may be a risk factor for impaired surgical outcomes.

Mid-Term outcomes following fresh-frozen humeral head osteochondral allograft reconstruction for reverse Hill Sachs lesion: a case series

Background

Locked posterior glenohumeral dislocations with a reverse Hill-Sachs impaction fracture involving less than 30% of the humeral head are most frequently treated with lesser tuberosity transfer into the defect, whereas those involving more than 50% undergo humeral head arthroplasty. Reconstruction of the defect with segmental femoral osteochondral allografts has been proposed to treat patients between these two ranges, but the medium−/long-term outcomes of this joint-preserving procedure are controversial.

Methods

Between 2001 and 2018, 12 consecutive patients with a unilateral locked posterior shoulder dislocation and an impaction fracture from 30 to 50% (mean 31% ± 1.32) of the humeral head were treated with segmental reconstruction of the defect with fresh-frozen humeral head osteochondral allografts. Patients were assessed clinically, radiographically and with computed tomography (CT) at a medium follow-up of 66 ± 50.25 months (range, 24–225).

Results

All twelve shoulders presented a slight limitation in anterior elevation (average, 166.6° ± 22.76). The mean active external rotation with the shoulder at 90° of abduction was 82.5° ± 6.61, and that with the arm held in stable adduction was 79.16 ± 18.80. The mean abduction was 156.25° ± 25.09.

The mean Constant-Murley score (CS) was 82 ± 15.09 points (range, 40–97 points), and the mean ASES was 94 ± 8.49 points. The mean pre- and postoperatively Western Ontario Shoulder Instability index (WOSI) was 236.5 ± 227.9 and 11.20 ± 10.85, respectively.

Development of osteoarthrosis (OA) was minimal. The average allograft resorption rate was 4% ± 2.4. There were no cases of failure (reoperation for any reason) in this series.

Conclusion

Segmental humeral head reconstruction with humeral head fresh-frozen osteochondral allografts provides good to excellent clinical results with low-grade OA and low allograft resorption in patients with locked posterior shoulder dislocation.

Trial registration

ClinicalTrials.gov PRS, ClinicalTrials.gov ID: NCT04823455. Registered 29 March 2021 - Retrospectively registered, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000AU8P&selectaction=Edit&uid=U0004J36&ts=12&cx=6cykp8

Level of evidence

Level IV, Case Series, Treatment Study.

Glenoid track measurement using magnetic resonance imaging arthrography is predictive of recurrent instability following arthroscopic shoulder stabilisation

PURPOSE

The primary aim of this study was to investigate medium-term survivorship following arthroscopic Bankart repair (ABR) for anterior glenohumeral instability. The secondary aim was to determine whether the pre-operative magnetic resonance (MR) arthrography glenoid track measurement predicted recurrent instability following ABR.

METHODS

Over a 9-year period (2008-2017), 215 patients underwent ABR. Median age was 26 years (IQR 22-32.5; range 14-77). There were 173 males (81%). 175 patients (81%) had available pre-operative MR arthrography, which was used to determine the presence of "off-track" bone loss. Retrospective analysis was undertaken to determine recurrence of instability at a median follow-up of 76 months (range 21-125 months). Survivorship analysis was undertaken using Kaplan-Meier methodology: the endpoints examined were repeat dislocation, revision stabilisation, and symptomatic instability.

RESULTS

56 patients (26%) presented with further instability, including 29 patients with recurrent dislocation and 15 patients required revision stabilisation. Cumulative incidence of instability was 10% at 1 year, 27% at 5 years and 28% at 7 years. No significant difference in instability was seen between men and women 7 years after stabilisation (19% vs 17%; p = 0.87). Age at time of surgery did not predict recurrence. "Off-track" lesions were identified in 29 patients (16.1%). The incidence of redislocation was significantly higher in these patients (24% vs 3%; p = 0.01; relative risk 7.2; 95% CI 2.45-20.5; p = 0.001). Recurrent instability without frank redislocation was also significantly higher in this group (60% vs 18%; RR 3.33, 95% CI 2.02-5.20; p < 0.0001).

CONCLUSIONS

This study has reported a significant rate of recurrent instability in longer-term follow-up after ABR. It has also identified pre-operative MR arthrography as an important predictor of recurrent instability, which may be used to risk stratify patients with anterior instability in a typical UK population.

LEVEL OF EVIDENCE

III (cohort study).

Fatal Outcome After Reduction of a Superior Shoulder Dislocation, A Case Report and Literature Review: A Case Report and Literature Review

CASE

An 81-year-old woman presented a superior glenohumeral dislocation after a low-energy fall, with a mechanism of axial load while the shoulder was in adduction and extension. After successful closed reduction, the patient presented sudden symptoms of severe vascular injury with a protruding axillary hematoma and hypovolemic shock.

CONCLUSION

Superior shoulder dislocations and vascular injuries are extremely rare among shoulder dislocations, especially after low-energy trauma. Vascular injuries may result in limb compromise and death. We highlight the importance of high clinical suspicion, particularly in superior dislocations, and the importance of prompt management of vascular complications to avoid catastrophic outcomes.

Arthroscopic bone block metal-free fixation for anterior shoulder instability. Short-term functional and radiological outcomes

INTRODUCTION

Anterior glenohumeral bone loss reconstruction reduces failure rates after soft tissue surgery in patients with large glenoid bone defects. Multiple bone block techniques have been described, most with metal hardware fixation. The objective of this study is to evaluate the safety, as well as the short-term functional and radiological results of an arthroscopic bone block metal-free fixation or bone block cerclage.

MATERIAL AND METHODS

Retrospective study of patients with glenohumeral instability and>15% glenoid bone loss operated during 2019 with follow-up of at least 12 months. Radiography and computerized tomography studies were performed. Functional outcomes were evaluated before and after surgery with the Western Ontario Shoulder Instability Index and Rowe score.

RESULTS

A total of 21 patients with a median age of 30.6 (SD 7.1) were included. All showed radiographic consolidation at 3 months follow-up. A percentage of 90.4 of bone grafts presented osteolysis at peripherical areas and 95.2% revealed consolidation in the areas with contact to the glenoid. The median glenoid estimated surface went from 79.3% before surgery to 98.4% at 12 months. Functional scores were statically significant (P<.001) for Western Ontario Shoulder Instability Index (35.6-86.9) and Rowe score (25.2 to 96.4). No serious complications were reported.

CONCLUSION

The bone block cerclage is a safe, metal-free technique that achieves total consolidation of the bone graft and favorable functional and radiological outcomes at 12 months follow-up.

Interobserver agreement for detecting Hill-Sachs lesions on magnetic resonance imaging

BACKGROUND

Our aim is to determine the interobserver reliability for surgeons to detect Hill-Sachs lesions on magnetic resonance imaging (MRI), the certainty of judgement, and the effects of surgeon characteristics on agreement.

METHODS

Twenty-nine patients with Hill-Sachs lesions or other lesions with a similar appearance on MRIs were presented to 20 surgeons without any patient characteristics. The surgeons answered questions on the presence of Hill-Sachs lesions and the certainty of diagnosis. Interobserver agreement was assessed using the Fleiss' kappa (κ) and percentage of agreement. Agreement between surgeons was compared using a technique similar to the pairwise t-test for means, based on large-sample linear approximation of Fleiss' kappa, with Bonferroni correction.

RESULTS

The agreement between surgeons in detecting Hill-Sachs lesions on MRI was fair (69% agreement; κ, 0.304; p<0.001). In 84% of the cases, surgeons were certain or highly certain about the presence of a Hill-Sachs lesion.

CONCLUSIONS

Although surgeons reported high levels of certainty for their ability to detect Hill-Sachs lesions, there was only a fair amount of agreement between surgeons in detecting Hill-Sachs lesions on MRI. This indicates that clear criteria for defining Hill-Sachs lesions are lacking, which hampers accurate diagnosis and can compromise treatment.

Evolving Concepts in the Management of Shoulder Instability

BACKGROUND

Shoulder instability exists on a spectrum ranging from subtle subluxation and pain to dislocation and can be the result of a traumatic event or repetitive microtrauma. Shoulder instability can result in significant disability and often requires surgical intervention, especially amongst younger, active patient populations. The optimal treatment of shoulder instability depends on the degree of instability and concomitant pathology involving the labrum, capsule, and bony anatomy of the glenoid and humeral head. Even with surgical intervention, recurrent instability remains a relatively common and difficult problem to address.

PURPOSE

With a focus on anterior instability, the purpose of this review article is to discuss the current assessment and treatment of shoulder instability, and highlight current and future treatment modalities, as well as to identify current trends and deficiencies in our current management. We also provide an algorithm for the surgical treatment of anterior shoulder instability.

METHODS

Literature databases were extensively searched for recent articles related to the mechanism, diagnosis, and treatment of shoulder instability to comprise a comprehensive review.

CONCLUSION

Although there are multiple treatment modalities available for shoulder instability, such as nonoperative management, open and arthroscopic Bankart repair, Latarjet procedures, and remplissage, orthopaedic surgeons continue to learn about the most appropriate method of management as increasing long-term outcomes become available.

Recurrent Instability and Surgery Are Common After Nonoperative Treatment of Posterior Glenohumeral Instability in NCAA Division I FBS Football Players

BACKGROUND

In-season return to play after anterior glenohumeral instability is associated with high rates of recurrent instability and the need for surgical stabilization. We are not aware of previous studies that have investigated in-season return to play after posterior glenohumeral instability; furthermore, as posterior shoulder instability in collision athletes occurs frequently, understanding the expected outcome of in-season athletes may improve the ability of physicians to provide athletes with a better understanding of the expected outcome of their injury and their ability to return to sport.

QUESTIONS/PURPOSES

(1) What proportion of athletes returned to play during the season after posterior instability in collegiate football players? (2) How much time did athletes lose to injury, what proportion of athletes opted to undergo surgery, and what proportion of athletes experienced recurrent instability after a posterior instability episode during a collegiate football season?

METHODS

A multicenter, prospective, observational study of National Collegiate Athletic Association (NCAA) Division 1 Football Bowl Subdivision athletes was performed at three US Military Service Academies. Ten athletes who sustained a posterior instability event during the regular football season and who pursued a course of nonoperative treatment were identified and prospectively observed through the subsequent season. All athletes in the observed cohort attempted an initial course of nonoperative treatment during the season. All athletes sustained subluxation events initially identified through history and physical examination at the time of injury. None of the athletes sustained a dislocation event requiring a manual reduction. Intraarticular pathology consisting of posterior labral pathology was further subsequently identified in all subjects via MRI arthrogram. Return to play was the primary outcome of interest. Time lost to injury, surgical intervention, and subsequent instability were secondary outcomes.

RESULTS

Of the 10 athletes who opted for a trial of initial nonoperative management, seven athletes were able to return to play during the same season. Although these seven athletes returned within 1 week of their injury (median of 1 day), 5 of 7 athletes sustained recurrent subluxation events with a median (range) of four subluxation events per athlete (0 to 8) during the remainder of the season. Seven athletes were treated surgically after the completion of their season, four of whom returned to football.

CONCLUSION

This study suggests that although collegiate football players are able to return to in-season sport after a posterior glenohumeral instability event, they will likely sustain multiple recurrent instability events and undergo surgery after the season is completed. The results of this study can help guide in-season management of posterior shoulder instability by allowing more appropriate postinjury counseling and decision making through the identification of those athletes who may require additional attention from medical staff during the season and possible modifications to training regimens to minimize long-term disability. Further prospective studies involving a larger cohort over several seasons should be performed through collaborative studies across the NCAA that better assess function and injury risk factors before beginning collegiate athletics. This would better characterize the natural history and associated functional limitations that athletes may encounter during their collegiate careers.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Chapter 6: Attritional Glenoid Bone Loss in the Shoulder: Operative Considerations

Patients with recurrent anterior shoulder instability often have glenoid bone loss present in addition to soft tissue pathologies. It is known that patients with significant glenoid bone loss are best treated with a boney augmentation procedure as opposed to a soft tissue Bankart repair because of the high rate of recurrent instability that results from a Bankart repair. Although the Latarjet technique has been the gold-standard treatment for patients with glenoid bone loss because of the low incidence of recurrent instability, it has a high complication rate and a steep learning curve. Herein, the authors present the technique and outcomes for arthroscopic anatomic glenoid reconstruction that has a similar complication rate to the Bankart repair but with a low recurrence rate similar to the Latarjet. This procedure is safe, has a short learning curve, low recurrence rate, and positive patient-reported outcomes.

Arthroscopic Knotless Subscapularis Bridge Technique for Reverse Hill-Sachs Lesion With Posterior Shoulder Instability

Posterior shoulder dislocations are an uncommon cause of glenohumeral instability; they are frequently missed and are associated with humeral head defects and capsulolabral lesions. Despite surgical treatment often being mandatory, there is still no standardized treatment for anterior impaction fractures of the humeral head (reverse Hill-Sachs lesions). Arthroscopic surgery is typically indicated, with a tendency toward resorting to knotless techniques in recent years. We present a method for the treatment of posterior shoulder dislocations with engaging reverse Hill-Sachs lesions that achieves full defect coverage using an arthroscopic all-in-the-box knotless subscapularis bridge technique with 2 anchors-with one crossing the subscapularis tendon and the other embracing it-along with posterior capsulolabral complex restoration. This promising technique is a potentially superior alternative for the treatment of these lesions that can also be used in the presence of concomitant partial subscapularis tears.

Arthroscopic Bankart revision using all suture anchor in recurrent anterior shoulder dislocation: A case report

•

All suture anchor has the same biomechanical strength as conventional metallic anchor.

•

Recurrent shoulder dislocation after arthroscopic Bankart repair is still a problem.

•

The all suture anchor technique offers benefit of bone preservation and strong fixation.

Introduction

Arthroscopic Bankart revision after recurrent shoulder dislocation is still a matter of discussion. Several factors are contributing to this injury. Recently the development of all suture anchors has grown in popularity in arthroscopic stabilization. It was proven to preserve bone stock, smaller in size thus more anchors can be made.

Presentation of case

We presented a case of 27-year-old woman with recurrent anterior dislocation after seven years of arthroscopic Bankart repair. Seven years before, we performed Bankart repair using three 2.8 mm fiber-wire anchor (FASTak® (Arthrex, Karsfield Germany)). For the revision surgery we performed arthroscopic revision using four all suture anchor technique (Y-Knot® Flex All-Suture Anchor, 1.3 mm – One strand of #2 Hi-Fi® (Conmed, New York)).

Discussion

From preoperative and intraoperative assessment, we found no anchor failure and no massive bony lesion. To preserve the bone stock we insert four all suture anchors between the old anchor. One year post-operative follow up showed that patient could gain normal range of movement. No early or late complications were observed.

Conclusion

Compared to the conventional metallic anchor, all suture anchor has the same biomechanical strength. Moreover due to its relatively small size, it can reserve bone stock and more anchors can be made thus adding more stability to the shoulder.

The Hill-Sachs interval to glenoid track width ratio is comparable to the instability severity index score for predicting risk of recurrent instability after arthroscopic Bankart repair

PURPOSE

The purpose of this study was to clinically validate the Hill-Sachs interval to glenoid track width ratio (H/G ratio) compared with the instability severity index (ISI) score for predicting an increased risk of recurrent instability after arthroscopic Bankart repair.

METHODS

A retrospective evaluation was performed using data from patients with anteroinferior shoulder instability who underwent arthroscopic Bankart repair with a follow-up period of at least 24 months. A receiver operating characteristic (ROC) curve was used to determine the optimal cut-off values for the H/G ratio and the ISI score to predict an increased risk of recurrent instability. The area under the ROC curve (AUC) of the two methods and the sensitivity and specificity of their optimal cut-off values were compared.

RESULTS

A total of 222 patients were included, among whom 31 (14.0%) experienced recurrent instability during the follow-up period. The optimal cut-off values for predicting an increased risk of recurrent instability were an H/G ratio of ≥ 0.7 and ISI score of ≥ 4. There were no significant differences between the AUC of the two methods (H/G ratio AUC = 0.821, standard error = 0.035 and ISI score AUC = 0.792, standard error = 0.04; n.s.) nor between the sensitivity and specificity of the optimal cut-off values (n.s. and n.s., respectively).

CONCLUSIONS

The H/G ratio is comparable to the ISI score for predicting an increased risk of recurrent instability after arthroscopic Bankart repair. Surgeons are recommended to consider other strategies to treat anterior shoulder instability if H/G ratio is ≥ 0.7.

LEVEL OF EVIDENCE

III.

Qualitative and quantitative analysis of glenoid bone stock and glenoid version: inter-reader analysis and correlation with rotator cuff tendinopathy and atrophy in patients with shoulder osteoarthritis

PURPOSE

Glenoid bone stock and morphology and rotator cuff muscle quality and tendon integrity affect the outcome of total shoulder arthroplasty. We hypothesized that glenoid bone loss correlates with rotator cuff muscle fatty infiltration (FI), tendinopathy, and atrophy.

DESIGN

Forty-three 3D CT scans and MRIs of 43 patients (mean age 62 years; SD 13 years; range 22-77 years) referred for primary shoulder pain were evaluated. Measurements of glenoid bone stock, version, and posterior humeral subluxation index (HSI) were assessed on an axial CT image reconstructed in the true scapular plane. Measurements utilized the Friedman line to approximate the pre-pathologic surface. Glenoid morphology was assigned by modified Walch classification. Rotator cuff FI, atrophy, and tendon integrity were assessed on corresponding MRIs.

RESULTS

There was a very strong negative correlation between increasing glenoid version and HSI (r = - 0.908; p < 0.0001). There was a moderately negative correlation between anterior bone loss and HSI (r = - 0.562; p < 0.0001) and a moderately positive correlation between posterior bone loss and HSI (r = 0.555; p < 0.0001). Subscapularis muscle FI correlated moderately with increased anterior and central bone loss and increased humeral head medialization (r = 0.512, p = 0.0294; r = 0.479, p = 0.033; r = 0.494, p = 0.0294; respectively). Inter-observer reliability (intra-class correlation coefficient [ICC] and kappa) was good to excellent for all measurements and grading.

CONCLUSION

Glenoid anteversion and anterior and posterior bone loss are associated with varying HSI. Subscapularis muscle FI, not tendon integrity, correlates to anterior and central glenoid erosion. The study adds evidence that neither rotator cuff tendinopathy nor muscle atrophy exhibits a significant relationship to HSI.

Use of the Contralateral Glenoid for Calculation of Glenoid Bone Loss: A Cadaveric Anthropometric Study

PURPOSE

The purpose of this study was to determine if there are significant side-to-side anthropometric differences between paired glenoids.

METHODS

Forty-six matched-pair cadaver glenoids were harvested, and their glenoid heights (GHs) and glenoid widths (GWs) were measured with digital calipers. The glenoid surface area was calculated using the standard assumption that the inferior two-thirds of the glenoid is a perfect circle.

RESULTS

There was a statistically significant difference between matched-pair GHs of 0.96 ± 3.07 mm (P = .020) and GWs of 0.46 ± 1.64 mm (P = .033). There was a significant difference of glenoid cavity area of 20.30 ± 81.53 mm2 (P = .044), or a difference of ∼3%. A total of 4 of 46 pairs of glenoids (8.6%) showed a difference in width >3 mm.

CONCLUSIONS

This study demonstrates the fallacy of use of the contralateral glenoid in measuring glenoid bone loss. Although many paired samples exhibited similar side-to-side glenoid measurements, the number of cadaveric pairs that showed differences of >3 mm was substantial. Caution should be taken when using calculation methods that include this assumption for surgical decision making, as surface area, GW, and GH were all shown to have statistically significant side-to-side differences in their measurements.

CLINICAL RELEVANCE

Many methods exist for measuring glenoid bone loss after anterior shoulder dislocation, but some of the current methods may be inaccurate and lead to unreliable estimations.

Correction to: Qualitative and quantitative analysis of glenoid bone stock and glenoid version: inter-reader analysis and correlation with rotator cuff tendinopathy and atrophy in patients with shoulder osteoarthritis

Purpose Glenoid bone stock and morphology and rotator cuff muscle quality and tendon integrity affect the outcome of total shoulder arthroplasty. We hypothesized that glenoid bone loss correlates with rotator cuff muscle fatty infiltration (FI), tendinopathy, and atrophy.Design Forty-three 3-D CT scans and MRIs of 43 patients (mean age 62 years; SD 13 years; range 22-77 years) referred for primary shoulder pain were evaluated. Measurements of glenoid bone stock, version, and posterior humeral subluxation index (HSI) were assessed on an axial CT image reconstructed in the true scapular plane. Measurements utilized the Friedman line to approximate the pre-pathologic surface. Glenoid morphology was assigned by modified Walch classification. Rotator cuff FI, atrophy, and tendon integrity were assessed on corresponding MRIs.Results There was a very strong negative correlation between increasing glenoid version and HSI (r = - 0.908; p < 0.0001). There was a moderately negative correlation between anterior bone loss and HSI (r = - 0.562; p < 0.0001) and a moderately positive correlation between posterior bone loss and HSI (r = 0.555; p < 0.0001). Subscapularis muscle FI correlated moderately with increased anterior and central bone loss and increased humeral head medialization (r = 0.512, p = 0.0294; r = 0.479, p = 0.033; r = 0.494, p = 0.0294, respectively). Inter-observer reliability (intra-class correlation coefficient [ICC] and kappa) was good to excellent for all measurements and grading.Conclusion Glenoid anteversion and anterior and posterior bone loss are associated with varying HSI. Subscapularis muscle FI, not tendon integrity, correlates to anterior and central glenoid erosion. The study adds evidence that neither rotator cuff tendinopathy nor muscle atrophy exhibits a significant relationship to HSI.

A Comparison of Physical Therapy Protocols Between Open Latarjet Coracoid Transfer and Arthroscopic Bankart Repair

CONTEXT

Recent studies examining return to sport after traumatic shoulder instability suggest faster return-to-sport time lines after bony stabilization when compared with soft tissue stabilization. The purpose of the current study was to define variability across online Latarjet rehabilitation protocols and to compare Latarjet with Bankart repair rehabilitation time lines.

EVIDENCE ACQUISITION

Online searches were utilized to identify publicly available rehabilitation protocols from Accreditation Council for Graduate Medical Education (ACGME)-accredited academic orthopaedic surgery programs.

STUDY DESIGN

Descriptive epidemiology study.

LEVEL OF EVIDENCE

Level 3.

RESULTS

Of the 183 ACGME-accredited orthopaedic programs reviewed, 14 institutions (7.65%) had publicly available rehabilitation protocols. A web-based search yielded 17 additional protocols from private sports medicine practices. Of the 31 protocols included, 31 (100%) recommended postoperative sling use and 26 (84%) recommended elbow, wrist, and hand range of motion exercises. Full passive forward flexion goals averaged 3.22 ± 2.38 weeks postoperatively, active range of motion began on average at 5.22 ± 1.28 weeks, and normal scapulothoracic motion by 9.26 ± 4.8 weeks postoperatively. Twenty (65%) protocols provided specific recommendations for return to nonoverhead sport-specific activities, beginning at an average of 17 ± 2.8 weeks postoperatively. This was compared with overhead sports or throwing activities, for which 18 (58%) of protocols recommended beginning at a similar average of 17.1 ± 3.3 weeks.

CONCLUSION

Similar to Bankart repair protocols, Latarjet rehabilitation protocols contain a high degree of variability with regard to exercises and motion goal recommendations. However, many milestones and start dates occur earlier in Latarjet protocols when compared with Bankart-specific protocols. Consequently, variability in the timing of rehabilitation goals may contribute to earlier return to play metrics identified in the broader literature for the Latarjet procedure when compared with arthroscopic Bankart repair.

STRENGTH OF RECOMMENDATION TAXONOMY (SORT)

Level C.