Prospective Evaluation of Glenoid Bone Loss After First-time and Recurrent Anterior Glenohumeral Instability Events

Arthroscopic Bone Block Stabilization for Anterior Shoulder Instability with Subcritical Glenohumeral Bone Loss

PURPOSE OF REVIEW

The management options for anterior shoulder instability with minimal bone loss or with critical bone loss are well established. However, there is less clear evidence to guide management for patients with subcritical bone loss, the spectrum of pathology where soft tissue repair alone is prone to higher rates of failures. In this range of bone loss, likely around 13.5% to 20%, the goal of surgery is to restore function and stability while limiting morbidity. As with many procedures in the shoulder, this decision should be tailored to patient anatomy, functional goals, and risk factors. This article provides a review of our current understanding of subcritical bone loss and treatment strategies as well as innovations in management.

RECENT FINDINGS

While surgeons have largely understood that restoration of anatomy is important to optimize outcomes after stabilization surgery, there is increasing evidence that reconstructing bony anatomy and addressing both osseous and soft tissue structures yields better results than either alone. Even in the setting of subcritical bone loss, there is likely a benefit to combined osseous augmentation with soft tissue management. Additionally, there is new evidence to support management of even on-track humeral lesions when the distance to dislocation is sufficiently small, particularly for athletes. Surgeons must balance bony and soft tissue restoration to achieve optimal outcomes for anterior instability with subcritical bone loss. There are still significant limitations in the literature and several emerging techniques for management will require further study to prove their long-term efficacy. Beyond surgery, there should be a focus on a collaborative treatment strategy with the surgeon, patient, and therapists to achieve high-level function and minimize recurrence.

Periostin Is a Biomarker for Anterior Shoulder Instability: Proteomic Analysis of Synovial Fluid

BACKGROUND

The incremental biological changes in the synovial microenvironment of the shoulder in acute and chronic instability that may contribute to joint degeneration are poorly understood. Proteomic analysis of synovial fluid in patients with shoulder instability may improve our understanding of proteins that are shed into shoulder synovial fluid after an injury.

HYPOTHESIS

Injury-specific factors such as the direction of instability and the severity of glenoid and humeral bone loss are associated with the proteome of synovial fluid in patients with shoulder instability.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Synovial fluid lavage samples were compared between patients with anterior (n = 12) and posterior (n = 8) instability and those without instability (n = 5). Synovial proteins were identified with liquid chromatography-tandem mass spectrometry. Orthogonal validation of protein targets found to be significant on tandem mass spectrometry was performed in a separate set of prospective patients with Western blotting. Data were processed and analyzed, and P values were adjusted with the Benjamini-Hochberg method for multiple comparisons.

RESULTS

A total of 25 patients were included. Tandem mass spectrometry identified 720 protein groups in synovial fluid of patients with shoulder instability. There were 4 synovial proteins that were significantly expressed in patients with anterior instability relative to posterior instability: periostin (POSTN) (adjusted P value = .03; log fold change [logFc] = 4.7), transforming growth factor beta-induced protein ig-h3 (adjusted P value = .05; logFc = 1.7), collagen type VI alpha-3 chain (adjusted P value = .04; logFc = 2.6), and coagulation factor V (adjusted P value = .04; logFc = -3.3). Among these targets, POSTN showed a moderate correlation with the Hill-Sachs lesion size (r = 0.7). Prospective validation with Western blotting confirmed a significantly higher level of POSTN in synovial fluid of patients with anterior instability (P = .00025; logFc = 5.1).

CONCLUSION

Proteomic analysis enriched our understanding of proteins that were secreted into shoulder synovial fluid of patients with shoulder instability. The identification of POSTN, a proinflammatory catabolic protein involved with tissue remodeling and repair, as a significant target in anterior shoulder instability is a novel finding. Therefore, further study is warranted to determine the role that POSTN may play in the progression of bone loss and posttraumatic osteoarthritis.

CLINICAL RELEVANCE

Proteomic analysis of synovial fluid in patients with shoulder instability improved our understanding of this abnormality after an injury.

Glenoid Concavity Affects Anterior Shoulder Stability in an Active-Assisted Biomechanical Model

Background

The treatment of bony glenoid defects after anteroinferior shoulder dislocation currently depends on the amount of glenoid bone loss (GBL). Recent studies have described the glenoid concavity as an essential factor for glenohumeral stability. The role of glenoid concavity in the presence of soft tissue and muscle forces is still unknown.

Hypothesis

Glenoid concavity would have a major impact on glenohumeral stability in an active-assisted biomechanical model including soft tissue and the rotator cuff's compression forces.

Study Design

Controlled laboratory study.

Methods

In 8 human shoulder specimens, individual coordinate systems were calculated based on anatomic landmarks. The glenoid concavity was measured biomechanically and based on computed tomography. Static load was applied to the rotator cuff tendons and the deltoid muscle. In a robotic test setup, anteriorly directed force was applied to the humeral head until translation of 5 mm (Nant) was achieved. Nant was used as a parameter indicating shoulder stability. This was performed in the following testing stages: (1) intact joint, (2) labral lesion, (3) 10% GBL, and (4) 20% GBL. The 8 specimens were divided equally into 2 subgroups (low concavity [LC] versus high concavity [HC]), with 4 specimens each, according to the previously measured concavity.

Results

Anterior glenohumeral stability was highly correlated with the native glenoid concavity (R 2 = 0.8). In the testing stages 1 to 3, we found a significantly higher mean stability in the HC subgroup compared with the LC subgroup (P≤ .0142). The HC subgroup still showed higher absolute Nant values with 20% GBL; however, there was no significant difference from the LC subgroup. The loss of stability in 20% GBL was correlated with the initial concavity (R 2 = 0.86). Thus, a higher loss of Nant in the HC subgroup was observed (P = .0049).

Conclusion

In an active-assisted model with intact soft tissue surrounding and muscular compression forces, the glenoid concavity correlates with shoulder stability. In bony defects, loss of concavity is an essential factor causing instability. Due to their significantly higher native stability, glenoids with HC can tolerate a higher amount of GBL.

Clinical Relevance

Glenoid concavity should be considered in an individualized treatment of bony glenoid defects. Further studies are required to establish reference values and develop therapeutic algorithms.

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

BACKGROUND

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

HYPOTHESIS

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

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

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

RESULTS

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

CONCLUSION

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

The Perfect Circle Technique Shows Poor Inter-rater Reliability in Measuring Anterior Glenoid Bone Loss on Magnetic Resonance Imaging

Purpose

To evaluate the reliability of the perfect circle methodology for measurement of glenoid bone loss in patients with anterior glenohumeral instability.

Methods

We performed a chart review of retrospectively collected patients who underwent isolated arthroscopic anterior labral repair between January 1 and June 30, 2021, using our institution's electronic medical records. The inclusion criteria included isolated anterior shoulder instability with anterior labral repair and corroborated tears on magnetic resonance imaging. A total of 9 raters, either sports or shoulder and elbow fellowship-trained orthopaedic surgeons, each evaluated the affected shoulder magnetic resonance imaging scans twice, with a minimum of 2 weeks between measurements. Measurements followed the "perfect circle" technique and included projected anterior-to-posterior glenoid diameter, amount of posterior bone loss, and percentage of posterior bone loss. Intrarater reliability and inter-rater reliability were then determined by calculating intraclass correlation coefficients (ICCs).

Results

Ten consecutive patients meeting the selection criteria were chosen for inclusion in this analysis. Average estimated bone loss for the cohort was 2.45 mm, and the mean estimated glenoid diameter of the involved shoulder was 28.82 mm. The average percentage of bone loss measured 8.54%. The ICC for interobserver reliability was 0.55 for the perfect circle diameter and 0.17 for the anterior bone loss measurement (poorly to moderately reliable). The ICC for intraobserver reliability was 0.69 for the perfect circle diameter and 0.71 for anterior bone loss (moderately reliable).

Conclusions

The perfect circle technique for estimating anterior glenoid bone loss on magnetic resonance imaging was found to have moderate intrarater reliability; however, reliability between observers was found to be moderate to poor.

Level of Evidence

Level IV, diagnostic case series.

Beyond guesswork: how accurate are surgeons at determining the degree of glenoid bone loss in instability surgery?

Background

Accurate measurement of glenoid bone loss (GBL) is critical to preoperative planning in cases of recurrent shoulder instability. The concept of critical bone loss has been established with a value of GBL >13.5% being associated with higher failure rate following arthroscopic Bankart Repair. Advanced imaging, such as magnetic resonance imaging (MRI) scans, can be used to quantify GBL prior to surgery using the best-fit circle technique. Surgeons have traditionally relied on visual inspection of the MRI scan preoperatively or on visual inspection of the glenoid at the time of arthroscopy to determine whether GBL is present. The purpose of this study is to determine if 3 fellowship-trained shoulder surgeons could adequately quantify GBL without using best-fit circle measurements on MRI.

Methods

A retrospective review was performed which included 122 patients over an 8-year period that had an arthroscopic Bankart repair performed by 3 fellowship-trained surgeons. In all patients, preoperative MRI scans were retrospectively measured using best-fit circle technique to determine true GBL and compare that to the surgeons' preoperative and intraoperative estimation of GBL.

Results

GBL was correctly identified in only 36% (18/50) of patients when the preoperative best-fit circle measurements were not made. Critical bone loss was missed in 9.8% (12/122) of patients in the study group. The estimated mean bone loss in that group by visual inspection was 11.3% compared to 16% true bone loss measured on MRI. Even in the 18 patients with some identified bone loss prior to surgery, critical bone loss was missed in 6 patients when using visual inspection of the MRI or intraoperative inspection alone.

Conclusion

Simple visual inspection of glenoid images on MRI scan and visual inspection of the glenoid at the time of surgery are inaccurate in determining the true extent of GBL especially in cases of subtle bone deficiency. Preoperative planning is dependent on the exact degree of bone deficiency and measurement on the MRI scan using the best-fit circle technique is recommended in all cases of instability surgery.

Preoperative planning with three-dimensional CT vs. three-dimensional magnetic resonance imaging does not change surgical management for shoulder instability

Background

This study aims to determine the effect of time and imaging modality (three-dimensional (3D) CT vs. 3D magnetic resonance imaging (MRI)) on the surgical procedure indicated for shoulder instability. The hypothesis is there will be no clinical difference in procedure selection between time and imaging modality.

Methods

Eleven shoulder surgeons were surveyed with the same ten shoulder instability clinical scenarios at three time points. All time points included history of present illness, musculoskeletal exam, radiographs, and standard two-dimensional MRI. To assess the effect of imaging modality, survey 1 included 3D MRI while survey 2 included a two-dimensional and 3D CT scan. To assess the effect of time, a retest was performed with survey 3 which was identical to survey 2. The outcome measured was whether surgeons made a "major" or "minor" surgical change between surveys.

Results

The average major change rate was 14.1% (standard deviation: 7.6%). The average minor change rate was 12.6% (standard deviation: 7.5%). Between survey 1 to the survey 2, the major change rate was 15.2%, compared to 13.1% when going from the second to the third survey (P = .68). The minior change rate between the first and second surveys was 12.1% and between the second to third interview was 13.1% (P = .8).

Discussion

The findings suggest that the major factor related to procedural changes was time between reviewing patient information. Furthermore, this study demonstrates that there remains significant intrasurgeon variability in selecting surgical procedures for shoulder instability. Lastly, the findings in this study suggest that 3D MRI is clinically equivalent to 3D CT in guiding shoulder instability surgical management.

Conclusion

This study demonstrates that there is significant variability in surgical procedure selection driven by time alone in shoulder instability. Surgical decision making with 3D MRI was similar to 3D CT scans and may be used by surgeons for preoperative planning.

Outcomes of the Latarjet procedure in female patients: A case series and matched-pair analysis

Background

The objective of this study was to retrospectively report on the outcomes of female patients undergoing the Latarjet procedure.

Methods

Female patients undergoing the Latarjet procedure with minimum 1 year follow-up were identified and contacted to obtain Numeric Pain Rating Scale (NPRS), Subjective Shoulder Value (SSV), and return to sport (RTS) data. Eligible females were then matched 1:1 with a male counterpart based on laterality and age (± 3 years), and outcomes compared.

Results

A total of 20 female patients with a mean follow-up of 73.8 months reported postoperative NPRS and SSV scores of 2.2  ±  2.3 and 69.3  ±  22.0, respectively. Of the nine athletes, 3 (33%) reported a successful RTS at a mean of 9 months. Four patients (20.0%) required reoperation at a mean of 27.1 months. The matched analysis demonstrated similar NPRS scores between male and female patients and a trend towards lower SSV scores and rates of RTS.

Conclusion

At mid-term follow-up female patients reported pain levels similar to female-specific literature reports, but overall low subjective shoulder function and RTS. Compared to propensity-matched males, females reported similar levels of pain, lower shoulder function, and lower rates of RTS, however, differences did not reach statistical significance.

Level of Evidence

IV, retrospective case series.

Establishing the Minimal Clinically Important Difference, Substantial Clinical Benefit, and Patient Acceptable Symptomatic State After Arthroscopic Posterior Labral Repair for Posterior Glenohumeral Instability

BACKGROUND

Posterior glenohumeral instability is an increasingly recognized cause of shoulder pain and dysfunction among young, active populations. Outcomes after posterior stabilization procedures are commonly assessed using patient-reported outcome measures including the Single Assessment Numeric Evaluation (SANE), the Rowe instability score, the American Shoulder and Elbow Surgeons (ASES) score, and the visual analog scale (VAS) for pain. The clinical significance thresholds for these measures after arthroscopic posterior labral repair (aPLR), however, remain undefined.

PURPOSE

We aimed to define the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for the SANE, Rowe score, and ASES score as well as the VAS pain after aPLR. Additionally, we sought to determine preoperative factors predictive of reaching, as well as failing to reach, clinical significance.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This study was a retrospective analysis of patient-reported outcome scores collected from patients who underwent aPLR between January 2011 and December 2018. To determine the clinically significant threshold that corresponded to achieving a meaningful outcome, the MCID, SCB, and PASS were calculated for the SANE, Rowe score, ASES score, and VAS pain utilizing either an anchor- or distribution-based method. Additionally, univariate and multivariate logistic regression analyses were performed to determine the factors associated with achieving, or not achieving, the MCID, SCB, and PASS.

RESULTS

A total of 73 patients with a mean follow-up of 82.55 ± 24.20 months were available for final analysis. MCID, SCB, and PASS values for the VAS pain were 1.10, 6, and 3, respectively; for the ASES score were 7.8, 34, and 80, respectively; for the SANE were 10.15, 33, and 85, respectively; and for the Rowe score were 11.3, 60, and 90, respectively. To meet the MCID, male sex (odds ratio [OR], 1.1639; P = .0293) was found to be a positive predictor for the VAS pain, and a lower preoperative SANE score (OR, 0.9939; P = .0003) was found to be a negative predictor for the SANE. Dominant arm involvement was associated with lower odds of achieving the PASS for the ASES score (OR, 0.7834; P = .0259) and VAS pain (OR, 0.7887; P = .0436). Patients who reported a history of shoulder trauma were more likely to reach the PASS for the SANE (OR, 1.3501; P = .0089), Rowe score (OR, 1.3938; P = .0052), and VAS pain (OR, 1.3507; P = .0104) as well as the SCB for the ASES score (OR, 1.2642; P = .0469) and SANE (OR, 1.2554; P = .0444). A higher preoperative VAS pain score was associated with higher odds of achieving the SCB for both the VAS pain (OR, 1.1653; P = .0110) and Rowe score (OR, 1.1282; P = .0175). Lastly, concomitant biceps tenodesis was associated with greater odds of achieving the SCB for the ASES score (OR, 1.3490; P = .0130) and reaching the PASS for the SANE (OR, 1.3825; P = .0038) and Rowe score (OR, 1.4040; P = .0035).

CONCLUSION

To our knowledge, this study is the first to define the MCID, SCB, and PASS for the ASES score, Rowe score, SANE, and VAS pain in patients undergoing aPLR. Furthermore, we found that patients who reported a history of shoulder trauma and those who underwent concomitant biceps tenodesis demonstrated a greater likelihood of achieving clinical significance. Dominant arm involvement was associated with lower odds of achieving clinical significance.

Review of Burkhart and DeBeer's (2000) article on traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repair: Where have we taken the concept of glenoid bone loss in 2023?

This classic discusses the original publication by Burkhart and DeBeer "Traumatic Glenohumeral Bone Defects and Their Relationship to Failure of Arthroscopic Bankart Repair" published in 2000 in Arthroscopy. At that time, the authors sought to understand the reasons behind the failure of arthroscopic soft tissue repair. Based on their findings, the authors introduced the concept of the inverted pear glenoid and engaging Hill-Sachs lesion which is now part of the orthopedic lexicon. The importance of bony pathologic changes in anterior glenohumeral instability has become so apparent, that it now forms the basis of clinical understanding and underpins treatment algorithms. Since this publication over 20 years ago, the idea of glenohumeral bone loss has been extensively explored and refined. There is no doubt of the importance of structural bone loss yet there is still uncertainty as to the best management of those with subcritical bone loss. The purpose of revisiting this classic article is to look at where we are in understanding recurrent instability and bony deficiency while appreciating how far we have come. This review begins with a detailed summary of the classic article along with a historic perspective. Next, we look at the current evidence as it pertains to the classic article and how modern technology and innovation has advanced our ability to assess and quantify glenohumeral bone loss. We finish with expert commentary on the topic from two current surgeons with a research interest in shoulder instability to offer an insight into how modern surgeons view and address this issue. One of the original authors also reflects on the topic. The findings of this classic study changed the way we think about shoulder instability and opened the doors to an exciting body of research that is still growing today. Future research offers an opportunity for high quality evidence to guide management in the group of patients with subcritical bone loss and we eagerly await the results.

Beach-Chair Versus Lateral Decubitus Positioning for Primary Arthroscopic Anterior Shoulder Stabilization: A Consecutive Series of 641 Shoulders

BACKGROUND

There are limited data comparing the beach-chair (BC) versus lateral decubitus (LD) position for arthroscopic anterior shoulder stabilization.

PURPOSE

To identify predictors of instability recurrence and revision after anterior shoulder stabilization and evaluate surgical position and glenoid bone loss as independent predictors of recurrence and revision at short- and midterm follow-ups.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A consecutive series of 641 arthroscopic anterior stabilization procedures were performed from 2005 to 2019. All shoulders were evaluated for glenohumeral bone loss on magnetic resonance imaging. The primary outcomes of interest were recurrence and revision. Multivariable logistic regression models were used to assess the relationships of outcomes with age, position, glenoid bone loss group, and track.

RESULTS

A total of 641 shoulders with a mean age of 22.3 years (SD, 4.45 years) underwent stabilization and were followed for a mean of 6 years. The overall 1-year recurrent instability rate was 3.3% (21/641) and the revision rate was 2.8% (18/641). At 1 year, recurrence was observed in 2.3% (11/487) and 6.5% (10/154) of BC and LD shoulders, respectively. The 5-year recurrence and revision rates were 15.7% (60/383) and 12.8% (49/383), respectively. At 5 years, recurrence was observed in 16.4% (48/293) and 13.3% (12/90) of BC and LD shoulders, respectively. Multivariable modeling demonstrated that surgical position was not associated with a risk of recurrence after 1 year (odds ratio [OR] for LD vs BC, 1.39; P = .56) and 5 years (OR for LD vs BC, 1.32; P = .43), although younger age at index surgery was associated with a higher risk of instability recurrence (OR, 1.73 per SD [4.1 years] decrease in age; P < .03). After 1 and 5 years, surgical position results were similar in a separate multivariable logistic regression model of revision surgery as the dependent variable, when adjusted for age, surgical position, bone loss group, and track. At 5 years, younger age was an independent risk factor for revision: OR 1.68 per SD (4.1 years) decrease in age (P < .05).

CONCLUSION

Among fellowship-trained orthopaedic surgeons, there was no difference in rates of recurrence and revision surgery after performing arthroscopic anterior stabilization in either the BC or the LD position at 1- and 5-year follow-ups. In multivariable analysis, younger age, but not surgical position, was an independent risk factor for recurrence.

Characterizing the Practices of Canadian Orthopedic Surgeons in the Management of patients With Anterior Glenohumeral Instability

OBJECTIVE

To determine the practice patterns of Canadian orthopedic surgeons in the management of patients with anterior glenohumeral instability (AGHI).

DESIGN

Cross-sectional survey.

SETTING

Canada.

PATIENTS OR OTHER PARTICIPANTS

Canadian orthopedic surgeons with membership in the Canadian Orthopedic Association or Canadian Shoulder and Elbow Surgeon group who had managed at least 1 patient with AGHI in the previous year.

INTERVENTIONS

A survey including demographics and questions on the management of patients with AGHI was completed. Statistical comparisons (χ 2 ) were completed with responses stratified using the instability severity index score (ISIS) in practice, years of practice, and surgical volumes.

MAIN OUTCOME MEASURES

Summary statistics were compiled, and response frequencies were considered for consensus (75%). Case series responses were stratified on use of the ISIS in practice, years of experience, and annual procedure volumes (χ 2 , P < 0.05).

RESULTS

Eighty orthopedic surgeons responded, with consensus on areas of diagnostic workup of AGHI, nonoperative management, and operative techniques. There was no consensus on indications for soft tissue and bony augmentation or postoperative management. There was no difference in practices based on the use of ISIS, years in practice, or surgical volumes.

CONCLUSIONS

Canadian orthopedic surgeons manage AGHI consistently with consensus achieved in preoperative diagnostics and operative techniques, although debate remains as to the indications for soft tissue and bony augmentation procedures.

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

Background

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

Purpose

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

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

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

Results

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

Conclusion

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

Arthroscopic Remplissage Combined With Bankart Repair Results in a Higher Rate of Return to Sport in Athletes Compared With Bankart Repair Alone or the Latarjet Procedure: A Systematic Review and Meta-analysis

BACKGROUND

Traumatic anterior shoulder instability affects athletes at a higher rate compared with the general population. In recent years, indications for arthroscopic remplissage, an adjunct procedure classically used to reduce the recurrence of anterior shoulder instability in patients with off-track Hill-Sachs lesions, have expanded.

PURPOSE

To investigate return-to-sport (RTS) rates, functional outcomes, and adverse events in athletes who underwent arthroscopic Bankart repair with remplissage compared with surgical alternatives such as Bankart repair alone or the Latarjet procedure.

STUDY DESIGN

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

METHODS

A literature review of the Embase, PubMed (MEDLINE), and Web of Science databases was conducted for articles published before May 22, 2022. For the systematic review, 16 of 457 studies that reported RTS rates at any time point after remplissage were deemed eligible for inclusion in quantitative analysis and 17 of 457 studies in qualitative analysis. For the meta-analysis, 8 of 457 studies reported RTS rates after remplissage compared with surgical alternatives including Bankart repair alone or the Latarjet procedure and were deemed eligible for inclusion.

RESULTS

In total, 538 athletes underwent remplissage and were included in the study. RTS at any level was achieved by 86% (395/457) of patients, and the odds of RTS at any level were significantly higher after remplissage compared with surgical alternatives (odds ratio [OR], 2.71 [95% CI, 1.14-6.43]; P = .02). The odds of RTS at a previous or higher level were also significantly higher after remplissage compared with surgical alternatives (OR, 2.07 [95% CI, 1.29-3.31]; P = .002). The mean Rowe score increased significantly from 43.9 ± 7.77 preoperatively (n = 173) to 92.2 ± 4.02 after remplissage (n = 397) (P < .001), but there was no significant difference in Rowe scores between remplissage and surgical alternatives (P = .54). After remplissage, the recurrence rate was 5.0% for athletes (n = 220) and 7.3% for all patients (n = 634), with a mean time to recurrence of 24.0 ± 12.5 months. Reoperations occurred in 3.6% of athletes (n = 110) and 4.1% of all patients (n = 445). Recurrence and reoperations were significantly less likely after remplissage compared with surgical alternatives (OR, 0.18 [95% CI, 0.08-0.39]; P < .001 and OR, 0.17 [95% CI, 0.06-0.50]; P = .001, respectively).

CONCLUSION

Arthroscopic Bankart repair with remplissage augmentation significantly improved RTS rates among athletes, both at any level and at previous levels of play. Additionally, remplissage appeared to significantly decrease recurrence and reoperation rates compared with surgical alternatives such as Bankart repair alone or the Latarjet procedure.

Arthroscopic repair with transosseous sling-suture technique for acute and chronic bony Bankart lesions

Background

Failure to fix the fractured fragment can result in bony fragment resorption and consequent glenoid bone loss. Current arthroscopic repair techniques might lead to insecure fixation and refracture. The purpose of this study was to evaluate the effectiveness of the transosseous sling-suture technique for bony Bankart lesions, and to compare the clinical outcomes for acute and chronic bony Bankart lesions treated with this technique.

Methods

A retrospective case series consisting of 46 patients with bony fracture of the glenoid rim following traumatic injury was identified from May 2015 to August 2020. The patients were divided into the acute lesion group and the chronic lesion group according to the time from first injury to surgery. The size of bone fragment was used to group the patients into the small and the medium sized fragment groups. All the patients underwent arthroscopic repairs using the transosseous sling-suture technique. Preoperative and postoperative evaluations including Rowe score, West Ontario Shoulder Instability Index (WOSI), Visual Analogue Scale (VAS) for pain scores, ROMs and number of dislocations were recorded. No significant differences were found in the comparisons of postoperative ROMs ang functional outcomes regarding between the small and the medium sized fragment groups.

Results

No dislocations occurred for both groups postoperatively. At the last follow-up, all the ROMs (including anterior flexion, abduction, external rotation and internal rotation at the side), the Rowe score, the WOSI score and the VAS score for pain in the both groups were significantly improved compared to the preoperative evaluations (all Ps < 0.001). In the comparisons between the acute and the chronic lesion groups, significantly greater anterior flexion (158.9 ± 8.9° vs. 153.0 ± 6.4°, P = 0.037), abduction (167.7 ± 10.1° vs. 161.0 ± 7.0°, P = 0.035) and external rotation at the side (88.3 ± 6.4° vs. 83.5 ± 5.5°, P = 0.024) were found in the acute lesion group. The comparisons of the Rowe score (86.0 ± 7.5 vs. 87.5 ± 10.6, P = 0.319), the WOSI score (223.5 ± 56.3 vs. 185.0 ± 79.9, P = 0.062), the VAS score for pain (0.4 ± 0.2 vs. 0.3 ± 0.2, P = 0.324) and the internal rotation at the side (74.6 ± 13.2° vs. 80.5 ± 11.1°, P = 0.116) between these two groups did not demonstrate significant differences between the two groups.

Conclusion

This arthroscopic transosseous sling-suture repair technique for shoulder anterior instability with acute and chronic bony Bankart lesion can restore joint stability, improve clinical outcomes and range of motion postoperatively. The acute bony Bankart lesion using the current technique can produce better range of motion compared to the chronic lesion.

Study design

Retrospective case series; Level of evidence, 4.

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

Background

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

Purpose

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

Study Design

Case series; Level of evidence, 4.

Methods

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

Results

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

Conclusion

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

First-time traumatic anterior shoulder dislocation: Approach for the primary health care physician

Traumatic anterior shoulder dislocation is a very common injury encountered in emergency rooms as well as in the primary health care physician's office. This injury occurs either in the setting of competitive or recreational sports injuries or as a high-energy injury during a fall or a road traffic accident. Common complications such as a recurrent dislocation can be predicted, monitored and prevented. Early appropriate treatment of associated cuff tears or fractures is associated with improved outcomes. There is a plethora of literature on the assessment and management of the primary anterior shoulder dislocation in specialised fields such as sports medicine, orthopaedic surgery and shoulder surgery. These studies are often highly technical, addressed to a particular subset of readers and often deal with one aspect of the management of the injury. This narrative aims to provide the reader with a simplified, evidence-based assessment and management approach for the first-time acute anterior shoulder dislocation. Emphasis is on closed reduction techniques, position and duration of immobilisation, and return to activities of life or sports. Risk factors for recurrence and other indications for primary referral to the orthopaedic surgeon are discussed. Other forms of shoulder instability such as posterior shoulder dislocation, inferior dislocation and multidirectional instability will not be the focus of this narrative.

Transosseous Equivalent Technique for Bony Bankart Repair

Bony Bankart lesions of the anterior glenoid arise from traumatic glenohumeral instability events and can predispose persons to recurrent instability if not surgically stabilized. Large osseous fragments, when repaired anatomically, have excellent stability and functional outcomes; however, techniques to achieve this repair are often either tenuous or overcomplicated. In this technique guide, we describe a repair technique based on established biomechanical principles that achieves a reliable, anatomic glenoid articular surface. This technique can be readily applied in most bony Bankart settings using standard anterior labral repair instrumentation and implants.

Gene Expression in Glenoid Articular Cartilage Varies Across Acute Instability, Chronic Instability, and Osteoarthritis

BACKGROUND

Shoulder instability is a common pathology associated with an elevated risk of osteoarthritis (OA). Little is known about gene expression in the cartilage of the glenohumeral joint after dislocation events, particularly as it relates to the risk of posttraumatic OA. This study tested the hypothesis that gene expression in glenoid cartilage varies among acute instability (<3 dislocations), chronic instability (≥3 dislocations), and OA.

METHODS

Articular cartilage was collected from the anteroinferior glenoid of consenting patients undergoing shoulder stabilization surgery (n = 17) or total shoulder arthroplasty (n = 16). Digital quantitative polymerase chain reaction was used to assess the relative expression of 57 genes (36 genes from OA risk allele studies, 21 genes from differential expression studies), comparing (1) OA versus instability (acute and chronic combined), (2) acute versus chronic instability, (3) OA versus acute instability, and (4) OA versus chronic instability.

RESULTS

The expression of 11 genes from OA risk allele studies and 9 genes from differential expression studies was significantly different between cartilage from patients with instability and those with OA. Pro-inflammatory genes from differential expression studies and genes from OA risk allele studies were more highly expressed in cartilage in the OA group compared with the instability group, which expressed higher levels of extracellular matrix and pro-anabolic genes. The expression of 14 genes from OA risk allele studies and 4 genes from differential expression studies, including pro-inflammatory genes, anti-anabolic genes, and multiple genes from OA risk allele studies, was higher in the acute instability group compared with the chronic instability group. Cartilage in the OA group displayed higher expression of CCL3, CHST11, GPR22, PRKAR2B, and PTGS2 than cartilage in the group with acute or chronic instability. Whereas cartilage in both the acute and chronic instability groups had higher expression of collagen genes, cartilage in the OA group had expression of a subset of genes from OA risk allele studies or from differential expression studies that was lower than in the acute group and higher than in the chronic group.

CONCLUSIONS

Glenoid cartilage has an inflammatory and catabolic phenotype in shoulders with OA but an anabolic phenotype in shoulders with instability. Cartilage from shoulders with acute instability displayed greater (cellular) metabolic activity compared with shoulders with chronic instability.

CLINICAL RELEVANCE

This exploratory study identified genes of interest, such as CCL3, CHST11, GPR22, PRKAR2B, and PTGS2, that have elevated expression in osteoarthritic glenoid cartilage. These findings provide new biological insight into the relationship between shoulder instability and OA, which could lead to strategies to predict and potentially modify patients' risk of degenerative arthritis due to shoulder instability.

Predictors of Bone Loss in Anterior Glenohumeral Instability

BACKGROUND

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

HYPOTHESIS/PURPOSE

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

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

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

RESULTS

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

CONCLUSION

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

REGISTRATION

NCT02075775 (ClinicalTrials.gov identifier).

Editorial Commentary: Urgency Toward Arthroscopic Bankart Repair Is Essential for Anterior Shoulder Dislocation: You Don't Have to Fix After the First Dislocation, but Definitely Before the Second!

While still hotly debated, primary arthroscopic management of the first-time anterior shoulder dislocation has an extensive list of known benefits: lower overall health care costs, improved patient-reported outcomes, a vast reduction in secondary instability, and higher quality-of-life measures. Yet, despite these meaningful contributions to health care quality, we continue to bypass the predictable success of an acute arthroscopic Bankart repair in order to tempt fate with "a trial" of nonoperative care for our young, high-risk collision athletes. Whether for the in-season athlete, the "early responder" with limited apprehension, subluxations with spontaneous reduction, or those stoically committed to nonsurgical care, we as physicians are often complicit in this shared risk taking and ceremonial weighing of the risks and benefits for treatment options after primary shoulder instability. Even just 1 additional episode of instability recurrence can double (or triple) the rate of glenohumeral bone loss. Furthermore, subsequent anterior shoulder instability compromises subjective shoulder function, heightens risk of secondary recurrence and/or revision, and increases the likelihood of requiring more advanced surgical management, such as with a Latarjet or other anterior bone block procedure. We must maintain a sense of urgency toward surgical treatment, particularly in young, high-demand athletes with persistent instability. To parrot the wisdom of our shoulder mentors, hear my humble plea: you don't have to fix the shoulder after the first anterior dislocation, but you should definitely do it before the second!

Increased Failure Rates After Arthroscopic Bankart Repair After Second Dislocation Compared to Primary Dislocation With Comparable Clinical Outcomes

PURPOSE

The purpose of this study was to compare rates of recurrent dislocation and postsurgical outcomes in patients undergoing arthroscopic Bankart repair for anterior shoulder instability immediately after a first-time traumatic anterior dislocation versus patients who sustained a second dislocation event after initial nonoperative management.

METHODS

A retrospective chart review was performed of patients undergoing primary arthroscopic stabilization for anterior shoulder instability without concomitant procedures and minimum 2-year clinical follow-up. Primary outcome was documentation of a recurrent shoulder dislocation. Secondary clinical outcomes included range of motion, Visual Analog Scale (VAS), American Shoulder and Elbow Surgeons Shoulder Score (ASES), and Shoulder Activity Scale (SAS).

RESULTS

Seventy-seven patients (mean age 21.3 years ± 7.3 years) met inclusion criteria. Sixty-three shoulders underwent surgical stabilization after a single shoulder dislocation, and 14 underwent surgery after 2 dislocations. Average follow-up was 35.9 months. The rate of recurrent dislocation was significantly higher in the 2-dislocation group compared to single dislocations (42.8% vs 14.2%, P = .03). No significant difference was present in range of motion, VAS, ASES, and SAS scores. The minimal clinically important difference (MCID) was 1.4 for VAS and 1.8 for SAS scores. The MCID was met or exceeded in the primary dislocation group in 31/38 (81.6%) patients for VAS, 23/31 (74.1%) for ASES, and 24/31 for SES (77.4%) scores. For the second dislocation cohort, MCID was met or exceeded in 7/9 (77.8%) for VAS, 4/7 (57.1%) for ASES, and 5/7 for SES (71.4%) scores.

CONCLUSION

Immediate arthroscopic surgical stabilization after a first-time anterior shoulder dislocation significantly decreases the risk of recurrent dislocation in comparison to those who undergo surgery after 2 dislocation events, with comparable clinical outcome scores. These findings suggest that patients who return to activities after a primary anterior shoulder dislocation and sustain just 1 additional dislocation event are at increased risk of a failing arthroscopic repair.

STUDY DESIGN

Retrospective comparative study; Level of evidence, 3.

First-time traumatic anterior shoulder dislocation: current concepts

The management of first-time traumatic anterior shoulder dislocations has been a topic of extensive study yet remains controversial. Development of a treatment plan requires an understanding of patient-specific considerations, including demographics, functional demands, and extent of pathology. Each of these can influence rates of recurrence and return to activity. The purpose of this review is to provide a framework for decision-making following a first-time anterior shoulder dislocation, with particular focus on the high-risk young and athletic population. A summary of surgical treatment options and their outcomes is outlined, along with future biomechanical and clinical perspectives.

Calculating glenoid bone loss based on glenoid height using ipsilateral three-dimensional computed tomography

PURPOSE

To investigate the relationship between glenoid width and other morphologic parameters using three-dimensional (3D) computed tomography (CT) images of native shoulders, and to create a new measurement tool to assess glenoid defects in a Canadian population with established anterior shoulder instability.

METHODS

Forty-three glenoid CT scans were analyzed for patients who underwent contralateral shoulder glenoid reconstruction for anterior shoulder instability between 2012 and 2020. Demographic data were obtained including age, gender and BMI. The subjects were excluded if they had a prior history of ipsilateral shoulder instability, shoulder fractures, or bone tumors. The following glenoid parameters were measured: width (W), height (H), anteroposterior (AP) depth, superior-inferior (SI) depth and version. The shape of the glenoid was also classified into pear, inverted comma or oval.

RESULTS

There were 35 male and 8 females with a mean age of 34.5 ± 12.9 years. The glenoid width was strongly correlated with the height (R² = 0.9) and a regression model equation was obtained: W (mm) = 2.5 + 0.7*H (mm). There was also strong correlation with gender (P < 0.001), glenoid shape (P = 0.030), AP and SI depths (P = 0.006 and P < 0.001, respectively). Male gender was associated with higher measurement values for all parameters. The most common glenoid shapes were the pear (46.5%) and oval morphotypes (39.6%) for the whole study group.

CONCLUSION

The native glenoid width can be estimated based on glenoid height using ipsilateral 3D CT. This may help with preoperative planning and surgical decision-making for patients with anterior shoulder instability and glenoid bone loss.

LEVEL OF EVIDENCE

III.

New bone formation after arthroscopic Bankart repair for unstable shoulders with an erosion-type glenoid defect

BACKGROUND

The purpose of the present study was to retrospectively evaluate new bone formation after arthroscopic Bankart repair (ABR) and the influence of new bone formation on recurrence in shoulders with an erosion-type glenoid defect.

METHODS

We analyzed data on shoulders with an erosion-type glenoid defect. Participants were patients who underwent computed tomography to evaluate new bone formation after ABR performed from 2004 to 2021 and were followed for a minimum of 2 years. We investigated the factors influencing new bone formation, in particular the presence of an intraoperative bone fragment, and the influence of new bone formation and its size on postoperative recurrence.

RESULTS

A total of 100 shoulders were included. The mean glenoid defect size was 10.1% ± 6.3% (range, 1.2%-31.5%). New bone formed postoperatively in 15 shoulders (15.0%) and was seen in significantly more shoulders with an intraoperative bone fragment (11 of 18, 61.1%) than in those without a fragment (4 of 82, 4.9%; P < .001). Recurrence occurred in 22 shoulders (22.0%), and the rate of recurrence was not different between shoulders with new bone formation (3 of 15, 20.0%) and without new bone formation (19 of 85, 22.4%; P = .999). Among the 15 shoulders with new bone formation, the size of the new bone fragments relative to glenoid width was <5% in 2 shoulders, 5%-<7.5% in 8 shoulders, 7.5%-<10% in 3 shoulders, and ≥10% in 2 shoulders; in all 3 shoulders with postoperative recurrence, the relative size was <7.5%.

CONCLUSIONS

Even in shoulders with an erosion-type glenoid defect, new bone may form after ABR, especially in shoulders with an intraoperative bone fragment. However, new bone formation does not decrease the rate of postoperative recurrence.

High failure rate after conservative treatment for recurrent shoulder dislocation without subjective apprehension on physical examination

PURPOSE

The purpose of this study was to investigate the outcomes of conservative treatment for recurrent shoulder dislocation without subjective apprehension, despite the presence of a Bankart lesion or glenoid defect.

METHODS

A retrospective analysis was performed for 92 patients with recurrent shoulder dislocation treated with conservative treatment due to negative apprehension between 2009 and 2018. The failure of the conservative treatment was defined as a dislocation or subluxation episode or subjective feeling of instability based on a positive apprehension. The Kaplan-Meier method was used to estimate failure rates over time, and a receiver operating characteristic (ROC) curve was constructed to determine a cut-off value for a glenoid defect. The clinical outcomes were compared between patients who completed conservative treatment without recurrence of instability (Group A) and those who failed and subsequently underwent surgical treatment (Group B) using shoulder functional scores and sports/recreation activity level.

RESULTS

This retrospective study included 61 of 92 eligible patients with recurrent shoulder dislocation. Among the 61 patients, conservative treatment failed in 46 (75.4%) over the 2-year study period. The cut-off value for a glenoid defect was 14.4%. The association between glenoid defect size (≥ 14.4% or as a continuous variable) and survival was statistically significant (p = 0.039 and p < 0.001, respectively). The mean glenoid defect size in Group B increased from 14.6 ± 3.0% to 17.3 ± 3.1% (p < 0.001), and clinical outcomes for Group A were inferior to those for Group B at the 24-month follow-up.

CONCLUSIONS

Conservative treatment for recurrent shoulder dislocation in patients without subjective apprehension showed a high failure rate during the study period, especially if the glenoid defect was ≥ 14.4% in size. Despite clinical improvement in patients who completed conservative treatment without recurrence, functional outcome scores and sport/recreation activity levels were better in the patients who underwent arthroscopic Bankart repair. Therefore, for recurrent anterior shoulder instability, even without subjective apprehension, surgical treatment is warranted over conservative treatment.

LEVEL OF EVIDENCE

Level IV.

Arthroscopic-Assisted Anterior Glenoid Reconstruction Using Nonrigid Fixation With Distal Tibia Osteochondral Allograft

Introduction:

Traumatic anterior glenohumeral instability events result in a capsulolabral (Bankart lesion) and/or osseous injury with subsequent attritional bone loss, particularly with recurrence. Up to 88% of patients with recurrent instability experience glenoid bone loss, which predisposes to future dislocations and subluxations, even with arthroscopic capsulolabral repair. The surgical management of glenoid bone loss includes a number of different techniques such as the Latarjet or coracoid transfer as well as other osseous and osteoarticular autografts and allografts. However, operative management of shoulder instability has increasingly shifted toward arthroscopic approaches with preservation of anatomy when possible.

Indications:

Arthroscopic-assisted allograft distal tibia bone block augmentation to the anterior glenoid is indicated for revision anterior glenohumeral instability procedures with anterior bone loss and in primary cases of anterior instability with critical bone loss.

Technique:

Our technique for nonrigid arthroscopic anterior glenoid reconstruction with allograft distal tibia and anterior labral repair is performed preferentially in the lateral position without necessitating patient repositioning. The preplanned tibial bone block is prepared on a back table prior to the arthroscopic procedure. After creation of portals and elevation of labral tissue, a guide and drill are used to introduce a retrograde reamer which is deployed to create a perpendicular edge for apposition of the allograft tibia. The bone block is then introduced through a rotator interval portal by pulling sutures retrograde through glenoid bone tunnels and is secured to the prepared surface medial to the liberated labrum. The articular surface of the graft and glenoid are aligned and suture-based fixation is used to compress the bone block against the native glenoid. The anterior labral tissue is then mobilized over the graft and repaired to the native glenoid when possible.

Description/Conclusion:

The benefits of allograft tibia augmentation for anterior instability with glenoid bone loss include an anatomic joint surface restoration including articular cartilage, lack of donor site morbidity, and a minimally invasive arthroscopic approach. When performed arthroscopically and with nonrigid fixation, this technique permits concurrent anterior labral repair and anatomic reconstruction, safe graft passage without necessity of a far medial portal, and expeditious return to function.

Increased superior translation following multiple simulated anterior dislocations of the shoulder

PURPOSE

Recurrent shoulder dislocations can result in kinematic changes of the glenohumeral joint. The number of prior shoulder dislocations may contribute to increased severity of capsulolabral lesions. The kinematics of the glenohumeral joint following multiple dislocations remain poorly understood. The purpose of this study was to assess the kinematics of the glenohumeral joint during anterior dislocations of the shoulder, and more specifically, altered translational motion following multiple dislocations. The kinematics of the glenohumeral joint were hypothesized to change and correlate with the number of dislocations.

METHODS

Eight fresh-frozen cadaveric shoulders were dissected free of all soft tissues except the glenohumeral capsule. Each joint was mounted in a robotic testing system. At 60 degrees of glenohumeral abduction, an internal and external rotational torque (1.1 Nm) were applied to the humerus, and the resulting joint kinematics were recorded. Anterior forces were applied to the humerus to anteriorly dislocate the shoulder and the resulting kinematics were recorded during each dislocation. Following each dislocation, the same rotational torque was applied to the humerus, and the resulting joint kinematics were also recorded. A repeated-measures analysis of variance (ANOVA) was used to compare the kinematics following each dislocation.

RESULTS

During the 7th, 8th, 9th, and 10th dislocations, the humerus significantly translated superiorly compared with the shoulder during the 1st dislocation (p < 0.05). Following the 3rd, 4th, 5th, and 10th dislocations, the humeral head significantly translated superiorly compared with the shoulder following the 1st dislocation in the position of 60 degrees of abduction in response to external rotation torque (p < 0.05).

CONCLUSION

Multiple anterior shoulder dislocations lead to abnormal translational kinematics and result in increased superior translation of the humerus. This may contribute to pathologic superior extension of capsulolabral injuries. Superior translation of the humerus with overhead motion in the setting of recurrent instability may also place the shoulder at risk for extension of the capsulolabral injuries.

Comparison of computed tomography and 3D magnetic resonance imaging in evaluating glenohumeral instability bone loss

BACKGROUND

To determine whether the addition of 3-dimensional (3D) magnetic resonance imaging (MRI) to standard MRI sequences is comparable to 3D computed tomographic (CT) scan evaluation of glenoid and humeral bone loss in glenohumeral instability.

METHODS

Eighteen patients who presented with glenohumeral instability were prospectively enrolled and received both MRI and CT within 1 week of each other. The MRI included an additional sequence (volumetric interpolated breath-hold examination [VIBE]) that underwent postprocessing for reformations. The addition of a VIBE protocol, on average, is an additional 4-4.5 minutes in the scanner. CT data also underwent 3D postprocessing, and therefore each patient had 4 imaging modalities (2D CT, 2D MRI, 3D CT reformats, and 3D MRI reformats). Each sequence underwent the following measurements from 2 separate reviewers: glenoid defect, glenoid defect percentage, humeral defect, humeral defect percentage, and evaluation of glenoid track and version. Paired t tests were used to assess differences between imaging modalities and χ² for glenoid track. Intra- and interobserver reliability were evaluated. Bland-Altman tests were also performed to assess the agreement between CT and MRI. In addition, we determined the cost of each imaging modality at our institution.

RESULTS

3D MRI measurements for glenoid and humeral bone loss measurements were comparable to 3D CT (Table 1). There were no significant differences for glenoid defect size and percentage, or humeral defect size and percentage (P > .05) (Table 2). Bland-Altman analysis demonstrated strong agreement, with small measurement errors for 3D CT and 3D MRI percentage glenoid bone loss. There was also no difference in evaluation for determining on vs. off track between any of the imaging modalities. Inter- and intrarater reliability was good to excellent for all CT and MRI measurements (r ≥ 0.7).

CONCLUSION

3D MRI measurements for bone loss in glenohumeral instability through use of VIBE sequence were equivalent to 3D CT. At our institution, undergoing MRI with 3D reconstruction was 1.67 times cheaper than MRI and CT with 3D reconstructions. 3D MRI may be a useful adjuvant to standard MRI sequences to allow concurrent soft tissue and accurate assessment of glenoid and humeral bone loss in glenohumeral instability.

Biomechanical analysis of anterior stability after 15% glenoid bone loss: comparison of Bankart repair, dynamic anterior stabilization, dynamic anterior stabilization with Bankart repair, and Latarjet

BACKGROUND

Dynamic anterior shoulder stabilization (DAS) with Bankart repair is a recently described stabilization technique thought to be more robust than an isolated Bankart repair while avoiding many coracoid transfer-related complications and technical demands. DAS involves transfer of the long head biceps through a subscapularis split to the anterior glenoid to create a sling effect. We hypothesize that DAS with Bankart repair will restore anterior stability in a human-cadaveric model with subcritical (15%) glenoid bone loss.

METHODS

Eight cadaveric shoulders were tested using an established shoulder simulator to record glenohumeral translations with an accuracy of ±0.2 mm. Shoulders were tested in 5 states-intact soft tissues, Bankart defect with 15% bone loss, isolated Bankart repair, DAS with Bankart repair, isolated DAS, and Latarjet. A 45 N anterior force was applied through the pectoralis major tendon, and translation of the humeral head was recorded and compared with repeated measures analysis of variance.

RESULTS

The anterior translation in the intact (native) glenoid was 4.7 mm at neutral position and 4.6 mm at 45° external rotation. Anterior translation significantly increased after introducing a Bankart defect with 15% glenoid bone loss to 9.1 mm (neutral, P = .002) and 9.5 mm (45° external rotation, P < .001). All repair conditions showed a significant decrease in anterior translation relative to Bankart defect. DAS with Bankart repair decreased anterior translation compared with the Bankart defect: 2.7 mm (neutral, P < .001) and 2.1 mm (45° external rotation, P < .001). DAS with Bankart repair significantly decreased anterior translation compared with the isolated Bankart repair (2.7 mm vs. 4.7 mm, P = .023) and the isolated DAS (2.7 mm vs. 4.3 mm, P = .041) in neutral position. The Latarjet procedure resulted in the greatest reduction in anterior translation compared with the Bankart defect: 1.2 mm (neutral, P < .001) and 1.9 mm (45° external rotation, P < .001).

CONCLUSIONS

DAS with Bankart repair is a viable alternative to restore anterior glenohumeral stability with a 15% glenoid defect at a greater degree than either DAS or Bankart repair alone. The Latarjet procedure was the most effective in reducing anterior translation but restrained the anterior translation significantly more than the native glenoid.

Anteroinferior Glenoid Rim Fractures Are a Relatively Common Finding in Shoulder Instability Patients Aged 50 Years or Older but May Not Portend a Worse Prognosis

Purpose

To investigate the incidence of anteroinferior glenoid rim fractures (AGRFs) after anterior shoulder instability (ASI) in patients aged 50 years or older, identify risk factors for surgical intervention for AGRFs, compare initial treatment strategies, and compare clinical outcomes of patients with and without associated AGRFs.

Methods

An established geographic medical record system was used to identify patients aged 50 years or older with ASI between 1994 and 2016. Patients with radiographic evidence of AGRFs were identified and matched 1:1 to patients without AGRFs. Outcome measures included recurrent instability, recurrent pain events, conversion to arthroplasty, and osteoarthritis graded with the Samilson-Prieto classification for post-instability arthritis.

Results

Overall, 177 patients were identified, with a mean follow-up period of 10.8 years. Of these patients, 41 (23.2%) had AGRFs and were matched to 41 control patients without AGRFs. The average age was 58.6 and 58.2 years for the AGRF and control groups, respectively. Rates of surgical intervention (27% vs 49%), recurrent instability (12% vs 20%), progression of osteoarthritis (34% vs 39%), and conversion to arthroplasty (2% vs 5%) were similar between AGRF patients and controls. For patients with AGRFs, increased bone fragment size (odds ratio, 1.1) and increased body mass index (odds ratio, 1.2) correlated with an increased risk of surgery. The cutoff value for an increased risk of surgery in patients with AGRFs was a fragment size 33% of the glenoid width or greater.

Conclusions

Of patients aged 50 years or older at presentation of ASI, 23.2% presented with an associated AGRF. A fragment size 33% of the glenoid width or greater and a higher patient body mass index were significant factors for surgical intervention; however, most patients did not require surgery and still showed acceptable clinical outcomes, and the most common reason for surgical intervention was a rotator cuff tear. Overall, the presence of an AGRF did not portend a worse prognosis as treatment strategies and long-term outcomes including recurrent instability, progression of osteoarthritis, and conversion to arthroplasty were similar to those in patients without AGRFs.

Level of Evidence

Level III, retrospective comparative study.

Prospective Evaluation of Posterior Glenoid Bone Loss After First-time and Recurrent Posterior Glenohumeral Instability Events

BACKGROUND

Although posterior glenohumeral instability is becoming an increasingly recognized cause of shoulder pain, the role of posterior glenoid bone loss on outcomes remains incompletely understood.

PURPOSES

To prospectively determine the amount of bone loss associated with posterior instability events and to determine predisposing factors based on preinstability imaging.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 1428 shoulders were evaluated prospectively for ≥4 years. At baseline, a subjective history of shoulder instability was ascertained for each patient, and bilateral noncontrast magnetic resonance imaging (MRI) scans of the shoulders were obtained regardless of any reported history of shoulder instability. The cohort was prospectively followed during the study period, and those who were diagnosed with posterior glenohumeral instability were identified. Postinjury MRI scans were obtained and compared with the screening MRI scans. Glenoid version, perfect-circle-based bone loss was measured for each patient's pre- and postinjury MRI scans using previously described methods.

RESULTS

Of the 1428 shoulders that were prospectively followed, 10 shoulders sustained a first-time posterior instability event and 3 shoulders sustained a recurrent posterior instability event. At baseline, 11 of 13 shoulders had some amount of glenoid dysplasia and/or bone loss. The change in glenoid bone loss was 5.4% along the axis of greatest loss (95% CI, 3.8%-7.0%; P = .009), 4.4% at the glenoid equator (95% CI, 2.7%-6.2%; P = .016), and 4.2% of total glenoid area (95% CI, 2.9%-5.3%; P = .002). Recurrent glenoid instability was associated with a greater amount of absolute bone loss along the axis of greatest loss compared with first-time instability (recurrent: 16.8% ± 1.1%; 95% CI, 14.6%-18.9%; first-time: 10.0% ± 1.5%; 95% CI, 7.0%-13.0%; P = .005). Baseline glenoid retroversion ≥10° was associated with a significantly greater percentage of bone loss along the axis of greatest loss (≥10° of retroversion: 13.5% ± 2.0%; 95% CI, 9.6%-17.4%; <10° of retroversion: 8.5% ± 0.8%; 95% CI, 7.0%-10.0%; P = .045).

CONCLUSIONS

Posterior glenohumeral instability events were associated with glenoid bone loss of 5%. The amount of glenoid bone loss after a recurrent posterior glenohumeral instability event was greater than that after first-time instability. Glenoid retroversion ≥10° was associated with a greater amount of posterior glenoid bone loss after a posterior instability event.

Novel anterior coracoglenoid line utilizing magnetic resonance imaging (MRI) corresponds with critical glenoid bone loss

OBJECTIVE

Glenoid bone loss is estimated using a best-fit circle method and requires software tools that may not be available. Our hypothesis is that a vertical reference line drawn parallel to the long axis of the glenoid and passing through the inflection point of the coracoid and glenoid will represent a demarcation line of approximately 20% of the glenoid. Our aim is to establish a more efficient method to estimate a surgical threshold for glenoid insufficiency.

METHODS

Fifty patients with normal glenoid anatomy were randomly chosen from an orthopedic surgeon's database. Two orthopedic surgeons utilized T1-weighted sagittal MRIs and the coracoglenoid line technique to determine the percentage of bony glenoid anterior to vertical line. Two musculoskeletal radiologists measured the same 50 glenoids using the circle technique. Differences were determined using dependent t test. Reliability was compared using interclass correlation coefficient and Kappa. Validity was compared using Pearson correlation coefficient.

RESULTS

Mean surface area of the glenoid anterior to the vertical line was on average 21.69% ± 3.12%. Surface area of the glenoid using the circle method was on average 20.86% ± 2.29%. Inter-rater reliability of the circle method was 0.553 (fair). Inter-rater reliability of the vertical line technique was 0.83 (excellent). There was a linear relationship between circle and vertical line measurements, r = 0.704 (moderate to high).

CONCLUSION

The coracoglenoid line appears to represent a line of demarcation of approximately 21% of glenoid bone anterior to the coracoglenoid line. Our technique was found to be reliable, valid, and accurate.

Dynamic Double-Sling Augmentation Prevents Anteroinferior Translation for Recurrent Anteroinferior Shoulder Dislocation With 20% Glenoid Bone Loss: A Cadaveric Biomechanical Study

PURPOSE

To biomechanically compare the dynamic double-sling with single-sling augmentation using the conjoined tendon (CT) with 20% of an anteroinferior glenoid bone defect under the high loads in shoulders.

METHODS

With the shoulder in 60° of glenohumeral abduction and 60° of external rotation, the 12 shoulders stability was tested sequentially in 5 conditions: intact, 20% glenoid bone loss, Bankart repair, single-sling augmentation with the CT, and double-sling augmentation with both the CT and long head of the biceps tendon (LHBT). The anteroinferior humeral head (HH) translation force of 20N, 30N, 40N, 50N, or 60N was applied to determine the shoulder stability in each condition.

RESULTS

The total HH translation over 8.77 mm represented the anteroinferior shoulder instability (95% confidence interval of bone defect: 7.76-8.77 mm). A significant increase in anteroinferior HH translation was demonstrated after the creation of 20% glenoid bone defect under the 20N translational force (10.52 ± 0.71 mm). Structural failure after the Bankart repair and the single-sling augmentation under the 30N (9.84 ± 1.25 mm) and 40N (9.59 ± 0.66 mm) translational forces, respectively, were observed. The double-sling augmentation effectively prevented the anteroinferior HH translation under the translational force of less than 40N, and only half of the augmentation structure (8.25 ± 1.66 mm) had failed under the 50N translational forces.

CONCLUSION

In the absence of any Hill-Sachs lesion and when tested at 60° abduction and external rotation in shoulders with 20% glenoid bone defects, at time-zero, the double-sling augmentation strategy could effectively prevent anteroinferior translation when compared with the Bankart repair or the single-sling augmentation technique under all magnitudes of the translational force in biomechanical simulation. Nevertheless, none of the constructs restored the HH translation to the normal intact state.

CLINICAL RELEVANCE

Double-sling augmentation technique may represent a reliable option for preventing anteroinferior translation.

Athletes with primary glenohumeral instability demonstrate lower rates of bone loss than those with recurrent instability and failed prior stabilization

BACKGROUND

The purpose of this study was to compare the preoperative magnetic resonance arthrography findings in patients who underwent glenohumeral stabilization with a history of primary instability, recurrent instability, or failed stabilization.

METHODS

All patients who presented with glenohumeral instability and underwent stabilization performed by a single surgeon in our institution between 2008 and 2020 were considered for inclusion in this study. The magnetic resonance arthrography findings of all patients were recorded. Imaging findings were compared between patients with primary instability, those with recurrent instability, and those with failed prior stabilization. P < .05 was considered statistically significant.

RESULTS

Overall, 871 patients were included, of whom 814 (93.5%) were male patients; the mean age was 23.1 years (range, 13-57 years). There were 200 patients with primary instability, 571 with recurrent instability, and 100 who required revision stabilization surgery, with no significant differences in demographic characteristics between the groups. A significantly higher amount of glenoid bone loss was noted in patients with recurrent instability (43.4%) and failed prior stabilization (56%) than in those with primary instability (26.5%) (P < .0001). Additionally, a significantly higher number of Hill-Sachs lesions were observed in patients with recurrent instability (70.1%) and failed prior stabilization (89%) than in those with primary instability (67.5%) (P < .0001). We found no significant differences between the groups regarding articular cartilage damage, glenolabral articular disruption, anterior labral periosteal sleeve avulsion, humeral avulsion of the glenohumeral ligaments, or superior labral anterior-posterior tears (P > .05).

CONCLUSION

Patients presenting for stabilization with recurrent instability or following a failed stabilization procedure have higher rates of glenohumeral bone loss than those with primary instability. Therefore, stabilization of primary instability, particularly in high-functioning athletes with a view to preventing recurrence, may reduce the overall progression of glenohumeral bone loss and potential subsequent inferior clinical outcomes.

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.

Anterior and Posterior Glenoid Bone Loss In Patients Receiving Surgery for Glenohumeral Instability Is Not the Same: A Comparative 3-Dimensional Imaging Analysis

Background

Methods

Results

Conclusion

Anterior Shoulder Instability Part I-Diagnosis, Nonoperative Management, and Bankart Repair-An International Consensus Statement

PURPOSE

The purpose of this study was to establish consensus statements via a modified Delphi process on the diagnosis, nonoperative management, and Bankart repair for anterior shoulder instability.

METHODS

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

RESULTS

The independent factors identified in the 2 statements that reached unanimous agreement in diagnosis and nonoperative management were age, gender, mechanism of injury, number of instability events, whether reduction was required, occupation, sport/position/level played, collision sport, glenoid or humeral bone-loss, and hyperlaxity. Of the 3 total statements reaching unanimous agreement in Bankart repair, additional factors included overhead sport participation, prior shoulder surgery, patient expectations, and ability to comply with postoperative rehabilitation. Additionally, there was unanimous agreement that complications are rare following Bankart repair and that recurrence rates can be diminished by a well-defined rehabilitation protocol, inferior anchor placement (5-8 mm apart), multiple small-anchor fixation points, treatment of concomitant pathologies, careful capsulolabral debridement/reattachment, and appropriate indications/assessment of risk factors.

CONCLUSION

Overall, 77% of statements reached unanimous or strong consensus. The statements that reached unanimous consensus were the aspects of patient history that should be evaluated in those with acute instability, the prognostic factors for nonoperative management, and Bankart repair. Furthermore, there was unanimous consensus on the steps to minimize complications for Bankart repair, and the placement of anchors 5-8 mm apart. Finally, there was no consensus on the optimal position for shoulder immobilization.

LEVEL OF EVIDENCE

Level V, expert opinion.

Open Stabilization Procedures of the Shoulder in the Athlete: Indications, Techniques, and Outcomes

Shoulder instability is a relatively common injury especially in the young athletic population and its surgical management continues to remain a controversial topic in sports medicine orthopedics. Anterior instability is the most common type encountered and is estimated to have an incidence rate of 0.08 per 1000 person-years in the general population; however, this figure is likely higher in the young athletic population. While in recent practice, arthroscopic surgery has become the new gold standard for management, reported failure rates as high as 26% and high recurrence rates in specific subpopulations such as young men in high collision sports have led to the consideration of alternative open procedures such as open Bankart repair, Latarjet, capsular shift, and glenoid bone grafting. These procedures may be preferred in specific patient subgroups such as young athletes involved in contact sports and those with Hill-Sachs defects and multidirectional instability, with postoperative recurrence rates of instability as low as 10%. The purpose of this review is to provide an overview of different open surgical techniques in the management of shoulder instability and summarize patient outcomes including recurrence rates for shoulder instability, return to sport, range of motion (ROM), muscle strength, and complications either individually by procedure or in comparison with other techniques, with special focus on their impact in the athletic population.

Team Approach: Treatment of Shoulder Instability in Athletes

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Shoulder instability is a complex problem with a high rate of recurrence in athletes. Treatment of a first-time subluxation or dislocation event is controversial and depends on patient-specific factors as well as the identified pathology.

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Athletic trainers and physical therapists are an integral part of the treatment team of an in-season athlete who has experienced a shoulder instability event. Through comprehensive physiological assessments, these providers can effectively suggest modifications to the patient's training regimen as well as an appropriate rehabilitation program.

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Surgical intervention for shoulder stabilization should use an individualized approach for technique and timing.

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A team-based approach is necessary to optimize the care of this high-demand, high-risk population.

Chondral Damage After Arthroscopic Repair Techniques for Acute Bony Bankart Lesions: A Biomechanical Study

BACKGROUND

Bony Bankart lesions can be encountered during treatment of shoulder instability. Current arthroscopic bony Bankart repair techniques involve intra-articular suture placement, but the effect of these repair techniques on the integrity of the humeral head articular surface warrants further investigation.

PURPOSE

To quantify the degree of humeral head articular cartilage damage secondary to current arthroscopic bony Bankart repair techniques in a cadaveric model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Testing was performed in 13 matched pairs of cadaveric glenoids with simulated bony Bankart fractures, with a defect width of 25% of the glenoid diameter. Half of the fractures were repaired with a double-row technique, while the contralateral glenoids were repaired with a single-row technique. Samples were subjected to 20,000 cycles of internal-external rotation across a 90° arc at 2 Hz after a compressive load of 750 N, or 90% body weight (whichever was less) was applied to simulate wear. Cartilage defects on the humeral head were quantified through a custom MATLAB script. Mean cartilage cutout differences were analyzed by the Wilcoxon rank-sum test.

RESULTS

Both single- and double-row repairs showed macroscopic damage. The histomorphometric analysis demonstrated that the double-row technique resulted in a significantly (P = .036) more chondral damage (mean, 57,489.1 µm²; SD, 61,262.2 µm²) than the single-row repair (mean, 28,763.5 µm²; SD, 24,4990.2 µm²).

CONCLUSION

Both single-row and double-row arthroscopic bony Bankart fixation techniques resulted in damage to the humeral head articular cartilage in the concavity-compression model utilized in this study. The double-row fixation technique resulted in a significantly increased cutout to the humeral head cartilage after simulated wear in this cadaveric model.

CLINICAL RELEVANCE

This study provides data demonstrating that placement of intra-articular suture during arthroscopic bony Bankart repair techniques may harm the humeral head cartilage. While the double-row repair of bony Bankart lesions is more stable, it results in increased cartilage damage. These findings suggest that alternative, cartilage-sparing arthroscopic techniques for bony Bankart repair should be investigated.

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.

The Bony Bankart: Clinical and Technical Considerations

Fractures of the anteroinferior aspect of the glenoid rim, known as a bony Bankart lesions, can occur frequently in the setting of traumatic anterior shoulder dislocation. If these lesions are large and are left untreated in active patients, then recurrent glenohumeral instability due to glenoid bone deficiency may occur. Therefore, the clinician must recognize these lesions when they occur and provide appropriate treatment to restore physiological joint stability. This article aims to provide an overview focusing on clinical and technical considerations in the diagnosis and treatment of bony Bankart lesions.

In-Season Management of Anterior Shoulder Instability

Anterior shoulder instability commonly occurs in young and active individuals, particularly those participating in contact or collision sports. At the intercollegiate level, rates of anterior instability have been reported to be 0.12 events per 1000 athlete exposures. The treatment of in-season athletes with anterior instability presents a challenge for the team physician. The desire to return to play within the same season with nonoperative management must be weighed against the increased risk of recurrence as well as athlete and team specific demands. The purpose of this chapter is to discuss the key considerations for the management of the athlete with anterior shoulder instability that occurs within the competitive season.

Editorial Commentary: Arthroscopic Shoulder Instability Surgery and Glenoid Bone Loss: A Paradigm Shift?

The successful treatment of shoulder instability, particularly in the setting of glenoid bone loss, is a challenging problem. There are several surgical options that are available for patients who have this clinical entity. Of these options, bone block procedures have become increasing common over the past several years, both for primary and revision surgery, with the aim to restore the native glenoid anatomy. The arthroscopic Eden-Hybinette procedure is a viable arthroscopic treatment option in patients who have anterior shoulder instability with anterior glenoid insufficiency. This technique has some distinct advantages over other bone block procedures, specifically the ability to avoid damage to the subscapularis and to preserve the coracoid process. In addition, the use of autograft has benefits over glenoid reconstruction procedures that use allograft, specifically pertaining to cost and availability.

Excellent Clinical and Radiological Midterm Outcomes for the Management of Recurrent Anterior Shoulder Instability by All-Arthroscopic Modified Eden-Hybinette Procedure Using Iliac Crest Autograft and Double-Pair Button Fixation System: 3-Year Clinical Case Series With No Loss to Follow-Up

PURPOSE

To evaluate the clinical, functional, and radiological midterm outcomes of the all-arthroscopic modified Eden-Hybinette procedure in patients with recurrent anterior shoulder instability.

METHODS

A retrospective, single-center case series with prospectively collected data was conducted. The inclusion criterion was traumatic recurrent anterior shoulder instability with significant glenoid bone loss; patients with atraumatic or multidirectional instability were excluded. An all-arthroscopic modified Eden-Hybinette procedure using iliac crest autograft and double-pair button fixation was carried out. All patients were postoperatively assessed for recurrence and apprehension. Shoulder range of motion values and functional scores, including American Shoulder and Elbow Surgeons Score, Oxford instability, Rowe instability, and Walch-Dupplay, were recorded. Graft positions, healing, and absorption were evaluated with computed tomography. Comparisons of values were performed with paired t tests for normally distributed differences and with nonparametric Wilcoxon's signed rank test otherwise.

RESULTS

The final study cohort included 28 patients, mean age 36 ± 10 years, and mean follow-up period 43 ± 6 months (range 36 to 53). Median glenoid bone loss was 12.4% (range 8% to 33%). No recurrence occurred, no subjective shoulder instability was reported, and no major complications were documented through the last follow-up. Postoperative shoulder range of motion had no significant differences compared with the healthy side. All final postoperative functional scores significantly increased to show excellent results compared with preoperative values. All grafts were positioned and healed optimally, and none was completely reabsorbed.

CONCLUSIONS

The all-arthroscopic modified Eden-Hybinette procedure is safe, leading to excellent clinical and radiological midterm outcomes in patients with recurrent anterior shoulder instability. This technique restores glenoid bone defects and preserves the normal shoulder anatomy.

LEVEL OF EVIDENCE

IV, therapeutic, retrospective case series.

Diagnosis and Management of Traumatic Anterior Shoulder Instability

Anterior shoulder instability is the most common form of shoulder instability and is usually because of a traumatic injury. Careful patient selection is key to a favorable outcome. Primary shoulder stabilization should be considered for patients with high risk of recurrence or for elite athletes. Soft-tissue injury to the labrum, capsule, glenohumeral ligament, and rotator cuff influence the outcome. Glenoid bone loss (GBL) and type of bone loss (on-track/off-track) are important factors when recommending treatment strategy. Identification and management of concomitant injuries are paramount. The physician should consider three-dimensional CT reconstructions and magnetic resonance arthrography when concomitant injury is suspected. Good results can be expected after Bankart repair in on-track Hill-Sachs lesions (HSLs) with GBL < 13.5%. Bankart repair without adjunct procedures is not recommended in off-track HSLs, regardless of the size of GBL. If GBL is 13.5% to 25% but on-track, adjunct procedures to Bankart repair should be considered (remplissage and inferior capsular shift). Bone block transfer is recommended when GBL > 20% to 25% or when the HSL is off-track. Fresh tibia allograft or lilac crest autograft are good treatment options after failed bone block procedure.