Stabilizing mechanism in bone-grafting of a large glenoid defect

Is the Subscapularis Function Preserved after the Latarjet Procedure? A Quantitative Analysis Using Positron Emission Tomography

Backgroud

In the Latarjet procedure, the subscapularis is divided at the superior two-thirds junction. It has been believed that this subscapularis split approach resulted in better internal rotation strength rather than an L-shaped subscapularis tenotomy. However, there are few studies demonstrating the preserved function of the subscapularis after the Latarjet procedure. The aim of the present study was to clarify the subscapularis activity using positron emission tomography (PET) in patients after the Latarjet procedure.

Methods

Six men who had undergone the Latarjet procedure were enrolled. The internal rotation exercise with elastic bands was performed with the arm at 0° and 90° of abduction. After the exercises, the patients had an intravenous injection of fluorine 18 fluorodeoxyglucose (18F FDG). Each PET image was fused to the corresponding computed tomography image to calculate the standardized uptake value (SUV). The internal rotation muscle strength was measured by a dynamometer.

Results

At 0° of abduction, the subscapularis SUVs of the involved side were significantly lower than those of the uninvolved side (p = 0.010), although there was no significant difference at 90° of abduction. The SUVs of the involved subscapularis were significantly lower at 0° of abduction than at 90° (p = 0.034). The internal rotation strength of the involved side was 81.1% ± 12.1% of the uninvolved side at 0° of abduction.

Conclusions

After the Latarjet procedure with the subscapularis split approach, subscapularis activity was well preserved at 90° of abduction. However, internal rotation strength was reduced by 19%.

Latarjet procedure versus iliac crest autograft transfer for anterior shoulder instability: a systematic review and meta-analysis of comparative studies

BACKGROUND

Anterior shoulder instability with glenoid bone loss presents a challenge in orthopedic surgery. The Latarjet and iliac crest bone graft transfer (ICBGT) procedures are commonly employed for its management, but direct comparative evidence is insufficient.

METHODS

Following PRISMA guidelines, a comprehensive search of PubMed, EMBASE, Cochrane Library, and Web of Science was conducted. Randomized controlled trials (RCTs) and cohort studies directly comparing the Latarjet and ICBGT procedures were included. Primary outcomes included postoperative recurrent instability, apprehension test, and complications, while secondary outcomes comprised Rowe score, Subjective Shoulder Value (SSV), pain level assessed by visual analogue scale (VAS), range of motion (ROM), and radiologic outcomes. Quality assessment was performed using RoB2 and MINORS tools. The weighted mean difference (WMD) for continuous variables and odds ratio (OR) for dichotomous variables were calculated, along with 95% confidence intervals (CIs). Meta-analysis was performed using RevMan 5.4.1 software.

RESULTS

A total of 6 studies with 409 patients were included. There was no significant difference in postoperative recurrent instability (OR, 1.33; 95% CI, 0.44 to 4.03; P = 0.61), positive apprehension test (OR, 0.78; 95% CI, 0.20 to 3.10; P = 0.73), revision surgery (OR, 2.06; 95% CI, 0.74 to 5.71; P = 0.16), mild complications (OR, 0.49; 95% CI, 0.23 to 1.06; 0.07), SSV (WMD, -1.94; 95% CI, -3.94 to 0.06; P = 0.06) or VAS score (WMD, 0.15; 95% CI, -0.17 to 0.47; P = 0.36) between the two procedures. The ICBGT group exhibited statistically superior Rowe scores (WMD, -3.10; 95% CI, -5.10 to -1.10; P = 0.002), as well as improved external (WMD, -5.32; 95% CI, -7.30 to -3.30; P < 0.001) and internal rotation (WMD, -5.11; 95% CI, -6.76 to -3.45; P < 0.001). However, these differences did not surpass the minimal clinically important difference (MCID). Radiological evaluations showed that the ICBGT procedure had statistically better outcomes in immediate glenoid augmentation, preservation and reduced fatty degeneration of the subscapularis (SSC) tendon, and graft remodeling at short-term follow-up.

CONCLUSIONS

The ICBGT procedure showed statistically superior Rowe scores and range of motion, but these differences may not be clinically significant. Both procedures had comparable outcomes in recurrent instability, apprehension test results, revision surgery, mild complications, SSV, and pain levels. ICBGT appears to offer advantages in glenoid augmentation and SSC preservation at short-term follow-up.

PROSPERO REGISTRATION ID

CRD42024586157.

Evaluation of throwing ability after coracoid transfer in non-overhead athletes

Background

Coracoid transfer is the most common procedure for the treatment of traumatic anterior shoulder dislocations with large glenoid bone defects; however, it is rarely used for the treatment of throwing shoulders because of possible postoperative limited range of motion. This study aimed to evaluate throwing function after coracoid transfer for shoulder instability.

Methods

The study included non-overhead athletes (n = 11; Bristow-Latarjet [BL] group) who suffered shoulder dislocation and underwent coracoid transfer on the dominant side of the shoulder and healthy volunteers (n = 20; C group) from the same population (overall age distribution: 18-22 years). All participants were evaluated for shoulder function including ball-throwing abilities (e.g., ball velocity and long-throw distance). In the primary analyses, we compared the maximum ball velocity and long-throw distance between the groups using the repeated 2-way analysis of variance. In secondary analyses, all other measurements were compared between the groups using the Mann-Whitney U test.

Results

In the primary analysis, mean maximum ball velocity and long-throw distance in the BL and C groups were 83.5 and 87.9 km/h versus 44.8 and 54.7 m, respectively, demonstrating no significant differences between the groups. In the secondary analysis, only the range of external rotation with the shoulder at the side was significantly lower in the BL group (P = .046).

Conclusion

The throwing ability after coracoid transfer in non-overhead athletes is acceptable compared to that in the matched population. Therefore, this procedure may be an option for treating traumatic anterior shoulder dislocations with large bone defects in athletes such as goalkeepers, handball, and basketball players at the recreational level.

Glenoid track revisited

The risk of Hill-Sachs lesion (HSL) to cause instability depends not only on the HSL but also on the glenoid size. Clinically, the only method to assess the risk of instability considering the dynamic interaction of both, the HSL together with the glenoid bone loss, is the glenoid track concept. Since it was introduced in a cadaveric study, its clinical efficacy and validity have been reported in the literature. Sometimes, the medial margin of the footprint (lateral margin of the glenoid track) is difficult to identify when a HSL is overriding the footprint. In such cases, we propose a method to draw an imaginary line connecting 2 landmarks. Although 3-dimensional computed tomography is the most accurate and widely used method to assess on/off-track lesions, our interest gradually is shifting toward magnetic resonance imaging (MRI), which has no radiation concern. The current magnetic resonance method is still under way. There are various risk factors influencing the recurrent instability after surgery. The glenoid track concept deals with only 1 of these factors, that is, instability caused by bony lesions. Therefore, the following 2 issues are important: 1) how to assess the glenoid track precisely and 2) how to incorporate other risk factors into consideration. The former can be achieved by obtaining the custom-made glenoid track width using not the fixed value of 83%, but more individualized value obtained by measuring the active horizontal extension angle of the opposite shoulder in the sitting position. At the same time, the gray zone (peripheral-track lesion) needs to be clearly defined. The latter can be achieved by incorporating the risk factors other than the bony lesions. One example is the Glenoid Track Instability Management Score (GTIMS), a combination of the glenoid track concept and the instability severity index score. This new scoring system is expected to increase the predictive potential of the scoring system, and accordingly to enhance clinical decision-making.

Inclusion of Glenoid Anteversion Provides a More Accurate Assessment of Glenoid Stability Using a Measuring Protocol for the Modified Bony Shoulder Stability Ratio

PURPOSE

To clarify whether there is a disparity between the conventional bony shoulder stability ratio (cBSSR) calculated using the method of Moroder et al. and the stability ratio (SR) obtained biomechanically and whether the modified bony shoulder stability ratio (mBSSR) calculated using the modified method, adjusted for glenoid anteversion, shows good consistency with the biomechanically determined SR.

METHODS

Forty-two glenoid models were successively constructed from seven cadaveric scapular bones, each with varying degrees of bone defect (intact condition and 2-, 4-, 6-, 8-, and 10-mm defects). The cBSSR and mBSSR were calculated using the conventional and modified radiologic protocols, respectively. A biomechanical experiment was conducted to measure the biomechanical SR of the glenoid model for accuracy validation. Linear regression analysis, intraclass correlation coefficient (ICC) calculation, Bland-Altman plot generation, and repeated-measures analysis of variance were performed to compare these methods to ascertain the impact of including glenoid anteversion on the accuracy of the bony shoulder stability ratio (BSSR).

RESULTS

The mBSSR, which included glenoid anteversion, showed a stronger correlation with the biomechanical SR compared with the cBSSR. Linear regression analysis showed R2 = 0.7727 and ICC = 0.726 for the mBSSR versus the biomechanical SR and showed R2 = 0.5507 and ICC = 0.363 for the cBSSR versus the biomechanical SR. Bland-Altman analysis revealed less bias between the mBSSR and biomechanical SR (bias, 0.0854; 95% confidence interval, -0.0762 to 0.2470) than between the cBSSR and biomechanical SR (bias, 0.1899; 95% confidence interval, 0.0039 to 0.3759). Repeated-measures analysis of variance confirmed a significant difference between the cBSSR and biomechanical SR (P = .002).

CONCLUSIONS

The inclusion of glenoid anteversion in mBSSR calculations provides a more accurate assessment of glenoid stability. Our findings indicate the need to consider anteversion adjustments in BSSR estimation.

CLINICAL RELEVANCE

Our research identified that conventional methods did not take glenoid anteversion into account. Through our comprehensive biomechanical experiment, we have shown that incorporating glenoid anteversion in the BSSR calculation yields a more precise assessment of glenoid stability, which can provide a crucial methodologic foundation for clinical assessment.

Bone block options for treating glenoid bone loss and glenohumeral instability: A systematic review

Background

To systematically review the literature assessing glenoid bone loss restoration by different bone block options and compare their dimensions.

Methods

Systematic examination of articles in PubMed and EMBASE databases was performed per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to find studies of bone grafts for treating anterior glenohumeral instability. Statistical analyses were conducted via Review Manager, and a p-value of <0.05 was statistically significant.

Results

Our review included 25 studies evaluating 870 shoulders. Traditional arc Latarjet (TL) had more depth than congruent arc Latarjet (CAL; p = 0.003). The coronal radii of curvature of TL, CAL, distal tibia, and iliac crest bone blocks were similar to native glenoid (p = 0.400, 0.817, 0.467, 0.216, respectively). CAL coracoid bone blocks restored significantly more glenoid surface area (30.3%) than TL bone blocks (p = 0.012). The glenoid width and surface area restoration by distal clavicle bone blocks were equivalent to TL (p = 0.058 and p = 0.103, respectively).

Discussion

The CAL technique restored higher percentages of glenoid surface area than TL but has less depth, which may increase fracture risk during screw insertion. The distal clavicle bone block is a suitable substitute to TL as it was equivalent regarding glenoid width and surface area restoration.

Bone formation of the coracoid bone graft after the Bristow procedure assessed using three-dimensional computed tomography

BACKGROUND

The Bristow procedure has been shown to be a reliable method to prevent recurrent anterior shoulder instability by compensating for glenoid bone loss and producing the sling effect. The degree of postoperative morphological change in the coracoid bone graft is speculated to influence glenohumeral joint stability; however, the details of these changes after the Bristow procedure remain unknown. This study was performed to quantify the postoperative change in the coracoid bone graft volume as assessed by three-dimensional computed tomography (3D-CT).

METHODS

The Bristow procedure was performed on 17 shoulders in 17 patients from August 2018 to January 2020. All patients were men, and their mean age at surgery was 17.9 years. The mean follow-up duration was 21.4 months. Within the first week after the operation (Time 0) and at the final follow-up, 3D-CT was used to determine the total coracoid bone graft volume. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) shoulder score, the University of California Los Angeles (UCLA) shoulder score, and the Western Ontario Shoulder Instability Index (WOSI).

RESULTS

The mean volume of the total coracoid bone graft was 1.26 ± 0.29 cm3 at Time 0 and 1.90 ± 0.36 cm3 at the final follow-up (p < 0.0001). The mean JOA score, UCLA score, and WOSI were significantly better at the final follow-up than preoperatively (p < 0.001). No postoperative infection, neurovascular injury, or recurrent instability of the glenohumeral joint occurred.

CONCLUSIONS

In the Bristow procedure, the volume of the total coracoid bone graft as shown by 3D-CT was significantly greater at the final follow-up than at Time 0, and bone formation of the coracoid bone graft was found after the Bristow procedure.

Improvement of coracoid process union rates: a comparative study of conventional open and arthroscopic-assisted Bristow procedures for treating anterior shoulder instability in rugby players

BACKGROUND

The Bristow coracoid transfer procedure is a reliable technique for treating anterior shoulder instability in patients with large glenoid bone loss or those involved in collision sports. However, its success is marred by its inferior bone union rate of the coracoid process as compared to the Latarjet procedure. This study aimed to evaluate whether arthroscopic confirmation of the secured coracoid fixation during the Bristow procedure improves the bone union rate and clinical outcomes as compared to the open procedure.

METHODS

We retrospectively reviewed 104 rugby players (n = 111 shoulders) who underwent an open (n = 66 shoulders) or arthroscopy (AS)-assisted (n = 45 shoulders) Bristow procedure at our center from 2007 to April 2019. In the AS-assisted group, the screw fixation and coracoid stability and contact were confirmed under arthroscopic visualization. Graft union was evaluated through computed tomography at 3 months, 6 months, and 1 year postoperatively. Patient-reported outcome measures were assessed based on the American Shoulder and Elbow Surgeons score, Rowe score, and satisfaction rate. Recurrence, the rate of return to play (RTP), and the frequency of pain after RTP were also assessed.

RESULTS

The mean follow-up period was 73.5 (range: 45-160) months for the open group and 32.3 (range: 24-56) months for the AS-assisted group. In the former, the rates of bone union were 50%, 72.7%, and 88.9% at 3 months, 6 months, and 1 year, respectively. In contrast, the AS-assisted group had significantly greater bone union rates-88.9%, 93.3%, and 95.6% at 3 months, 6 months, and 1 year, respectively. Both groups showed significant improvement in the American Shoulder and Elbow Surgeons and Rowe scores compared to preoperative values as well as high satisfaction rates (open: 92%; AS-assisted: 95.7%). There were no statistically significant differences in the recurrence and RTP rates as well as the frequency of pain after RTP between the 2 groups.

CONCLUSION

The AS-assisted procedure allows early and high bone healing without compromising the clinical outcomes.

Current Evidence and Techniques for Arthroscopic Bone Augmentation

The indications for bone block augmentation of the glenoid following recurrent anterior shoulder instability are expanding. Arthroscopic anatomic glenoid reconstruction (AAGR) is an evolving technique with similar clinical results to the Latarjet procedure and other open bone block procedures. Multiple types of bone grafts and fixation techniques have been described, with varying results on bony integration, resorption, articular congruity, and recurrence rates. This review focuses on biomechanics, patient workup, indications, current evidence, and the authors' preferred surgical technique for AAGR.

Management of bone loss in anterior shoulder instability

Bone defects are frequently observed in anterior shoulder instability. Over the last decade, knowledge of the association of bone loss with increased failure rates of soft-tissue repair has shifted the surgical management of chronic shoulder instability. On the glenoid side, there is no controversy about the critical glenoid bone loss being 20%. However, poor outcomes have been described even with a subcritical glenoid bone defect as low as 13.5%. On the humeral side, the Hill-Sachs lesion should be evaluated concomitantly with the glenoid defect as the two sides of the same bipolar lesion which interact in the instability process, as described by the glenoid track concept. We advocate adding remplissage to every Bankart repair in patients with a Hill-Sachs lesion, regardless of the glenoid bone loss. When critical or subcritical glenoid bone loss occurs in active patients (> 15%) or bipolar off-track lesions, we should consider anterior glenoid bone reconstructions. The techniques have evolved significantly over the last two decades, moving from open procedures to arthroscopic, and from screw fixation to metal-free fixation. The new arthroscopic techniques of glenoid bone reconstruction procedures allow precise positioning of the graft, identification, and treatment of concomitant injuries with low morbidity and faster recovery. Given the problems associated with bone resorption and metal hardware protrusion, the new metal-free techniques for Latarjet or free bone block procedures seem a good solution to avoid these complications, although no long-term data are yet available.

The Latarjet Procedure for Recurrent Anterior Shoulder Instability in the Contact Athlete

In young athletes, anterior shoulder instability is a prevalent condition. Because of high-energy traumas, contact athletes often suffer recurrent instability, bone loss and postoperative recurrences. Patients younger than 20 years, symptomatic for more than 6 months, with ≥ 2 dislocations, with off-track Hill-Sachs lesion, glenoid bone loss, ALPSA lesion, Instability Severity Index Score > 3, and Glenoid Track Instability Management Score > 3 are at higher risk of failure. In cases of multiple dislocations with critical or subcritical glenoid bone loss, notably in collision and contact athletes, the Latarjet procedure is widely recognized as the treatment of choice.

Functional Anatomy and Biomechanics of Shoulder Instability

The glenohumeral joint is the least congruent and least constrained joint with a complex relationship of static and dynamic stabilizers to balance its native mobility with functional stability. In the young athlete, anterior shoulder instability is multifactorial and can be a challenge to treat, requiring a patient-specific treatment approach. Surgical decision-making must consider patient-specific factors such as age, sport activity and level, underlying ligamentous laxity, and goals for return to activity, in addition to careful scrutiny of the underlying pathology to include humeral and glenoid bone loss and surrounding scapular bone morphology.

Sutures, Screws, Buttons, and Anchors: A Review of Current Bone Graft Fixation Devices for Glenoid Bone Loss in the Unstable Shoulder

PURPOSE OF REVIEW

Anterior shoulder instability is associated with concomitant injury to several stabilizing structures of the shoulder, including glenoid bone loss. While instability is most common in young athletes and patients with predisposing conditions of hyperlaxity, recurrent shoulder instability can occur throughout various age ranges and may lead to longer term effects including pain and shoulder arthritis. Glenoid bone loss exceeding certain thresholds is generally treated by glenoid reconstruction via bone block augmentation to adequately stabilize the glenohumeral joint. These procedures increase the width of the articular surface on which the humeral head can translate before dislocation and, based on the procedure performed, provide a sling effect via the conjoined tendon, and increase tension to support the anterior capsule. The purpose of this review is to summarize the available literature regarding bone block fixation techniques.

RECENT DEVELOPMENTS

Various fixation techniques have been utilized to secure bone block transfers. Though screw fixation has traditionally been used for bone block fixation, suture buttons, suture anchors, and all-suture techniques have been utilized in attempts to avoid complications associated with the use of screws. Biomechanical studies report variable force-resistance, displacement, and mode of failure when comparing screw to suture button-based fixation of glenoid bone blocks. Clinical and radiographic studies have shown these novel suture-based techniques to be comparable, and in some cases advantageous, to traditional screw fixation techniques. While screw fixation has long been the standard of care in glenoid bone block procedures, it is associated with high complication rates, leading surgeons to endeavor toward new fixation techniques. In available biomechanical studies, screw fixation has consistently demonstrated high maximal load-to-failure and displacement with cyclic loading. Studies have reported similar clinical and radiographic outcomes in both screw and suture-based fixation methods, with evidence of reduced bone resorption with suture fixation. While suture button fixation is associated with a higher rate of recurrent instability, overall complication rates are low. Future research should address biomechanical shortcomings of suture-based fixation techniques and continue to assess long-term follow-up of patients treated with each fixation method.

Moment arms of the coracobrachialis and short head of biceps following a Latarjet procedure: a modeling study

BACKGROUND

The Latarjet procedure transfers the coracoid process to the anterior glenoid. This prevents recurrent anterior humeral dislocation but alters the origins of the coracobrachialis (CBR) and short head of the biceps (SHB). The impact of this alteration on the moment arms of these muscles has not been examined.

METHODS

The Newcastle Shoulder Model was updated with 15 healthy cadaveric bone models to create customized shoulder models. The CBR and SHB muscles were attached to the anterior glenoid via an elliptical wrapping object. Muscle moment arms were calculated for abduction, forward flexion, scapular plane elevation, and internal rotation with 20° and 90° of abduction. Statistical comparison of moment arms between native and Latarjet shoulders was performed using spm1D.

RESULTS

By transferring the origins of the CBR and SHB to the anterior glenoid, both muscles had extension moment arms during glenohumeral elevation in the coronal, sagittal, and scapular planes. Their average moment arms during abduction (-30.4 ± 3.2 mm for CBR and -29.8 ± 3.0 mm for SHB) and forward flexion (-26.0 ± 3.1 mm for CBR and -26.2 ± 3.2 mm for SHB) suggested that their role after the Latarjet procedure changed compared with their role in the native shoulder (P < .001). At higher abduction levels, both the muscles had higher internal rotation moment arms compared with the native shoulder.

CONCLUSION

The Latarjet procedure affected the moment arms of the CBR and SHB. Both muscles had increased extension and internal rotation moment arms at higher degrees of elevation compared with the native shoulders. This finding suggests that these muscles act as dynamic stabilizers after the Latarjet procedure.

Is Revision Arthroscopic Bankart Repair a Viable Option? A Systematic Review of Recurrent Instability following Bankart Repair

Background/Objectives: Recurrent shoulder instability following Bankart lesion repair often necessitates surgical revision. This systematic review aims to understand the failure rates of arthroscopic revision Bankart repair. Methods: Following the PRISMA guidelines and registered on PROSPERO, this systematic review examined twenty-five articles written between 2000 and 2024. Two independent reviewers assessed eligibility across three databases, focusing on recurrent instability as the primary endpoint, while also noting functional measures, adverse events, revision operations, and return-to-sport rates when available. Results: The key surgical techniques for recurrent instability post-Bankart repair were identified, with revision arthroscopic Bankart being the most common (685/1032). A comparative analysis revealed a significantly lower recurrence for open coracoid transfer compared to arthroscopic revision Bankart repair (9.67% vs. 17.14%; p < 0.001), while no significant difference was observed between remplissage plus Bankart repair and Bankart repair alone (23.75% vs. 17.14%; p = 0.24). The majority of studies did not include supracritical glenoid bone loss or engaging Hill-Sachs lesions, and neither subcritical nor non-engaging lesions significantly influenced recurrence rates (p = 0.85 and p = 0.80, respectively). Conclusions: Revision arthroscopic Bankart repair remains a viable option in the absence of bipolar bone loss; however, open coracoid transfer appears to have lower recurrence rates than arthroscopic Bankart repair, consistent with prior evidence. Further studies should define cutoffs and investigate the roles of critical glenoid bone loss and off-track Hill-Sachs lesions. Preoperative measurements of GBL on three-dimensional computed tomography and characterizing lesions based on glenoid track will help surgeons to choose ideal candidates for arthroscopic revision Bankart repair.

Clinical Significance Thresholds in Primary and Revision Latarjet Procedures With Comparable Outcome Achievements

BACKGROUND

Given the variability across populations and settings, defining the MCID and the PASS for the Rowe and ASOSS scores and patients undergoing primary and revision Latarjet it is essential to have accurate benchmarks relevant to these groups when interpreting clinical results.

PURPOSE

To determine the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) thresholds for the visual analog scale (VAS) for pain during sports, Athletic Shoulder Outcome Scoring System (ASOSS), and Rowe scores after primary and revision Latarjet procedures for treatment of shoulder instability.

STUDY DESIGN

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

METHODS

Between January 2018 and January 2020, a retrospective review of 149 patients undergoing primary Latarjet (n = 82) and revision Latarjet (n = 67) to treat shoulder instability was performed in a single institution. Patient-reported outcome measures were collected preoperatively and 1 year postoperatively. The delta was defined as the change between the pre- and postoperative scores. Distribution-based and anchored-based approaches were used to estimate the MCID and the PASS, respectively. The optimal cutoff point and the percentage of patients achieving those thresholds were also calculated.

RESULTS

The distribution-based MCIDs after primary Latarjet were 1.1, 7.5, and 9.6 for the VAS, Rowe, and ASOSS scores, respectively. The rates of patients who achieved the MCID thresholds were 93.9%, 98.7%, and 100% for the VAS, Rowe, and ASOSS scores, respectively. The PASS thresholds after primary Latarjet were ≤1, ≥90, and ≥85 for the VAS, Rowe, and ASOSS scores, respectively. The percentages of patients who achieved PASS thresholds were 82.9%, 89%, and 86.5% for the VAS, Rowe, and ASOSS scores, respectively. The distribution-based MCIDs after revision Latarjet were 0.6, 6.2, and 3.4 for the VAS, Rowe, and ASOSS scores, respectively. The rates of patients who achieved MCID thresholds were 89.3%, 100%, and 100% for the VAS, Rowe, and ASOSS scores, respectively. The PASS thresholds were ≤3, ≥87, and ≥86 after revision Latarjet for the VAS, Rowe, and ASOSS scores, respectively. The rates of patients who achieved the PASS thresholds were 88%, 88%, and 91% for the VAS, Rowe, and ASOSS, respectively.

CONCLUSION

This study identified useful values for the MCID and PASS thresholds in VAS, Rowe, and ASOSS scores after primary and revision Latarjet procedures for treating shoulder instability. Most patients achieved MCID and PASS benchmarks, indicating successful primary and revision Latarjet procedure outcomes. These metrics can serve as valuable parameters when analyzing parameters in future studies and have the potential to enhance patient care by optimizing treatment strategies and surgical decision making.

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.

Inlay structure can improve bone graft stability in the Bristow procedure

BACKGROUND

Compared with the Latarjet procedure, the Bristow procedure has a lower screw-related complication rate but poor bone healing. A modified Inlay Bristow procedure has been reported to significantly improve the bone healing rate, but the biomechanical mechanism is unclear. The aim of this study was to evaluate the biomechanical stability of the bone graft between a modified Inlay Bristow procedure and the classic Bristow procedure.

METHODS

Sixteen left scapula models (Sawbones, Composite Scapula, and fourth generation) were randomly divided into 2 groups (8:8). The bone graft in the first group was fixed with a 3.5 mm screw using the Inlay structure. The bone graft in the second group was fixed with a 3.5 mm screw via the traditional method. The maximum cyclic displacement, ultimate failure load and stiffness were evaluated biomechanically. The failure type was recorded for each model.

RESULTS

Cyclic loading tests demonstrated that the maximum cyclic displacement of the Inlay procedure was significantly smaller (P = .001) than that of the classic procedure. The Inlay Bristow technique resulted in a significantly higher (P = .024) ultimate failure load than the classic Bristow technique. The stiffness of the classic group was 19.17 ± 4.01 N/mm and that of the inlay group was 22.34 ± 5.35 N/mm (P = .232). Failure was mainly due to bone graft fractures through the drill hole or glenoid bone fractures.

CONCLUSION

Inlay Bristow fixation of the bone graft in a Sawbones model provides significantly stronger fixation and better time point zero stability than classic Bristow fixation, suggesting a higher likelihood of graft union.

Primary bone graft stability after Latarjet surgery: biomechanical evaluation of a fixation technique with metal-free all-suture cerclage vs. cortical screws

BACKGROUND

To reduce hardware-related complications in coracoid graft fixation to the anterior aspect of the glenoid, a metal-free Latarjet technique was recently introduced. The aim of this study was to compare the primary stability of a classic Latarjet procedure with 2 metal screws to a novel metal-free, all-suture cerclage method. It is hypothesized that fixation of the coracoid graft with 2 malleolar screws will provide higher primary stability compared with an all-suture cerclage technique.

METHODS

This biomechanical in vitro study was conducted on 12 fresh-frozen cadaveric shoulders (6 matched pairs) with a mean donor age of 80 years (range, 67-89 years). Coracoid graft fixation was performed using a recently introduced all-suture cerclage technique (group A) or a classic Latarjet technique with two 4.5-mm malleolar screws (group B). The conjoint tendon was loaded with a static force of 10 N to simulate the sling effect. Graft loading with a probe head consisted of 6 ascending load levels (10-50 N, 10-100 N, 10-150 N, 10-200 N, 10-250 N, and 10-300 N) with 100 cycles each at 1 Hz. Relative motion of the bone graft to the glenoid was measured using an optic 3-dimensional system.

RESULTS

While loading the conjoint tendon with 10 N, no difference in mean displacement of the bone-graft was found between both groups (P = .144). During cyclic loading, a significant difference in relative displacement for both groups was already detected in load level 1 (group A: 2398.8 μm vs. group B: 125.7 μm; P = .024), and this trend continued with the following load levels (P < .05).

DISCUSSION AND CONCLUSION

The study demonstrated that the innovative metal-free, all-suture cerclage fixation technique results in higher micromotion than the classic coracoid graft fixation with 2 malleolar screws. According to the present biomechanical investigation, shoulders treated with a metal-free all-suture cerclage technique might need adapted rehabilitation protocols to protect the construct and allow for graft healing.

Association of the Stability Ratio With Postoperative Clinical Function and Recurrence of Instability in Patients With Anterior Shoulder Instability: A Retrospective Cohort Study

Background

The stability ratio (SR) is used to assess the stability of the glenoid in anterior shoulder instability (ASI). However, the association between the SR and postoperative clinical function and instability recurrence after arthroscopic Bankart repair is unknown.

Hypothesis

Patients with a higher SR would have better postoperative clinical scores and a lower incidence of recurrent instability than patients with a lower SR after arthroscopic Bankart repair.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 62 patients who underwent arthroscopic Bankart repair for ASI between 2013 and 2019 were enrolled. All patients had at least 2 years of follow-up data. The preoperative SR was calculated via biomechanical testing based on patient-specific 3-dimensional glenoid models, and patients were evenly divided into 2 groups: high SR (≥16.13%) and low SR (<16.13%). Baseline information (patient characteristics, clinical history, bone defect area [BDA], and SR), clinical scores at the final follow-up (Single Assessment Numerical Evaluation, Western Ontario Shoulder Index, and American Shoulder and Elbow Surgeons), and instability recurrence were compared between the 2 groups.

Results

No significant differences were found in the baseline information between the high- and low-SR groups, except for the BDA (8.5% [high-SR group] vs 11.9% [low-SR group]; P = .01). No patients in the high-SR group had recurrent instability, while 6 patients (19.4%) had recurrent instability in the low-SR group (P = .02). Patients in the high-SR group had superior clinical outcomes compared with those in the low-SR group in terms of postoperative Western Ontario Shoulder Index scores (median, 205 vs 410, respectively; P = .006) and American Shoulder and Elbow Surgeons scores (median, 98.3 vs 95, respectively; P = .02).

Conclusion

In the present study, the SR was significantly associated with postoperative clinical function and recurrence of instability after arthroscopic Bankart repair in patients with ASI.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

Background

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

Purpose

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

Study Design

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

Methods

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

Results

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

Conclusion

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

Determining optimal length of coracoid graft in the modified Bristow procedure for anterior shoulder instability: A three-dimensional finite element analysis

BACKGROUND

There is a lack of consensus concerning the coracoid graft length in the modified Bristow procedure.

OBJECTIVE

We attempted to determine the optimal graft length using the three-dimensional finite element method.

METHODS

In a shoulder model with a 25% anterior glenoid defect, a coracoid graft of varying lengths (5, 10, 15, and 20 mm) was fixed using a half-threaded screw. First, a compressive load of 500 N was applied to the screw head to determine the graft failure load during screw tightening. Next, a tensile load (200 N) was applied to the graft to determine the failure load due to biceps muscle traction.

RESULTS

In the screw compression, the failure loads in the 5-, 10-, 15-, and 20-mm models were 252, 370, 377, and 331 N, respectively. In the tensile load applied to the coracoid graft, the failure load exceeded 200 N for both the 5- and 10-mm models.

CONCLUSION

The 5-mm graft had a high risk of fracture during intraoperative screw tightening. As for the biceps muscle traction, the 5- and 10-mm-grafts had a lower failure risk than the 15- and 20-mm-grafts. Therefore, we believe that the optimal length of the coracoid graft is 10 mm in the modified Bristow procedure.

Biomechanical Evaluation of the 2 Different Levels of Coracoid Graft Positions in the Latarjet Procedure for Anterior Shoulder Instability

Background

In the Latarjet procedure, the ideal placement of the coracoid graft in the medial-lateral position is flush with the anterior glenoid rim. However, the ideal position of the graft in the superior-inferior position (sagittal plane) for restoring glenohumeral joint stability is still controversial.

Purpose

To compare coracoid graft clockface positions between the traditional 3 to 5 o'clock and a more inferior (for the right shoulder) 4 to 6 o'clock with regard to glenohumeral joint stability in the Latarjet procedure.

Study Design

Controlled laboratory study.

Methods

A total of 10 fresh-frozen cadaveric shoulders were tested in a dynamic, custom-built robotic shoulder model. Each shoulder was loaded with a 50-N compressive load while an 80-N force was applied in the anteroinferior axes at 90° of abduction and 60° of shoulder external rotation. Four conditions were tested: (1) intact, (2) 6-mm glenoid bone loss (GBL), (3) Latarjet procedure fixed at 3- to 5-o'clock position, and (4) Latarjet procedure fixed at 4- to 6-o'clock position. The stability ratio (SR) and degree of lateral humeral displacement (LHD) were recorded. A 1-factor random-intercepts linear mixed-effects model and Tukey method were used for statistical analysis.

Results

Compared with the intact state (1.77 ± 0.11), the SR was significantly lower after creating a 6-mm GBL (1.14 ± 0.61, P = .009), with no significant difference in SR after Latarjet 3 to 5 o'clock (1.51 ± 0.70, P = .51) or 4 to 6 o'clock (1.55 ± 0.68, P = .52). Compared with the intact state (6.48 ± 2.24 mm), LHD decreased significantly after GBL (3.16 ± 1.56 mm, P < .001) and Latarjet 4 to 6 o'clock (5.48 ± 3.39 mm, P < .001). Displacement decreased significantly after Latarjet 3 to 5 o'clock (4.78 ± 2.50 mm, P = .04) compared with the intact state but not after Latarjet 4 to 6 o'clock (P = .71).

Conclusion

The Latarjet procedure in both coracoid graft positions (3-5 and 4-6 o'clock) restored the SR to the values measured in the intact state. A more inferior graft position (fixed at 4-6 o'clock) may improve shoulder biomechanics, but additional work is needed to establish clinical relevance.

Clinical Relevance

An inferior coracoid graft fixation, the 4- to 6-o'clock position, may benefit in restoring normal shoulder biomechanics after the Latarjet procedure.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Controlled laboratory study.

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL RELEVANCE

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

Acromion and Distal Clavicle Grafts for Arthroscopic Glenoid Reconstruction

BACKGROUND

We intended to determine if an acromion or distal clavicle bone graft could restore large glenoid defects using two novel, screw-free graft fixation techniques.

METHODS

Twenty-four sawbone shoulder models were divided into four groups (n = 6 per group) according to fixation technique and bone graft: (1) modified buckle-down technique with clavicle graft, (2) modified buckle-down technique with acromion graft, (3) cross-link technique with acromion graft, (4) cross-link technique with clavicle graft. Testing was performed sequentially in (1) intact models, (2) after creation of a 30% by-width glenoid defect and (3) after repair. The shoulder joint was translated anteriorly, and glenohumeral contact pressures and load were measured to quantify the biomechanical stability.

RESULTS

Maximum contact pressures were restored to 42-56% of intact glenoid using acromion and clavicle grafts with novel fixation techniques. Acromion grafts attained higher maximum contact pressures than clavicle grafts in all groups. Peak translational forces increased by 171-368% after all repairs.

CONCLUSIONS

This controlled laboratory study on sawbone models found that both the acromion and distal clavicle are suitable autologous bone graft options for treating large anterior glenoid defects, having appropriate dimensions and contours for reconstructing the glenoid arc. The modified buckle-down and cross-link techniques are two graft fixation techniques that restore stability to the shoulder joint upon repairing a large glenoid defect and are advantageous in being screw-free and simple to execute.

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

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

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

Background

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

Purpose

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

Study Design

Cohort study; Level of evidence, 3.

Methods

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

Results

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

Conclusion

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

Functional biomechanical comparison of Latarjet vs. distal tibial osteochondral allograft for anterior glenoid defect reconstruction

INTRODUCTION

Glenoid reconstruction is indicated for recurrent glenohumeral instability with significant glenoid bone deficiency. Coracoid autograft (Latarjet) and distal tibial osteochondral allograft (DTA) reconstructions have been used to successfully restore glenohumeral stability. Relative advantages and disadvantages associated with each reconstruction technique have been described. However, direct comparisons of functional glenohumeral biomechanics associated with Latarjet vs. DTA reconstruction are lacking. This study was designed to compare these 2 glenoid reconstruction techniques with respect to joint kinematics and cartilage pressure mapping using a robotic testing system.

METHODS

In accordance with institutional review board policies, human cadaveric shoulders (n = 8) were cyclically tested in the neutral position and 90° of external rotation with 60° and 90° of abduction under a 45-N joint-compression load to measure clinically relevant translations, loads, and torques. Joint contact pressure maps were obtained under a 120-N joint-compression load using pressure mapping sensors. After confirming that a 25% anterior glenoid defect resulted in glenohumeral dislocation, testing was performed to compare 3 conditions: native intact glenoid, 25% anterior glenoid defect with Latarjet reconstruction, and 25% anterior glenoid defect with DTA reconstruction. Analyses of variance and t tests were used to analyze data with statistical significance set at P < .05.

RESULTS

Significant differences in anterior translation, inferior drawer, anterior drawer, compression loads, horizontal abduction, negative elevation (adduction), and external rotation torques during cyclical testing in 90° of external rotation with 60° and/or 90° of abduction were noted when comparing the 2 different glenoid bone reconstruction techniques to native, intact shoulders. The only significant difference between Latarjet and DTA reconstructions for measured translations, loads, and torques was a significantly higher absolute maximum compressive load for Latarjet compared to DTA at 60° of abduction.

CONCLUSION

Latarjet coracoid osseous autograft and distal tibial osteochondral allograft reconstructions of large (25%) glenoid bone defects prevent failure (dislocation) and are associated with significant glenohumeral kinematic differences that largely confer less translation, load, and torque on the joint in abduction when compared to the native state. These findings suggest that these 2 surgical techniques exhibit similar glenohumeral kinematics such that each provides adequate functional stability following anterior glenoid bone reconstruction. Joint compression load and articular contact pressure distribution may favor distal tibial osteochondral allograft reconstruction for treatment of large (25%) anterior glenoid bone defects associated with shoulder instability.

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

Background

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

Purpose/Hypothesis

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

Study Design

Cohort study; Level of evidence, 3.

Methods

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

Results

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

Conclusion

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

Latarjet Procedure to Restore Glenohumeral Stability in a Patient With a Postage Stamp Fracture

The "postage stamp fracture" is an anterior glenoid rim fracture following arthroscopic repair of a Bankart lesion. Often occurring at the time of an acute trauma, a fracture line propagates though the previous Bankart repair anchor sites, resulting in recurrent anterior instability of the glenohumeral joint. The resultant glenoid rim fracture edge gives a similar appearance as the edge of a stamp, with the osseous edge having the classic "perforation" pattern. When patients present with a postage stamp fracture, even in the setting of subcritical glenoid bone loss, we believe that additional soft-tissue stabilization procedures and/or fracture fixation pose a significant risk of failure. In our opinion, a Latarjet procedure is recommended in a majority of patients with a postage stamp fracture for restoration of glenohumeral stability. The procedure offers a reliable, reproducible surgical intervention that controls for many of the factors that can make arthroscopic revision unreliable, such as poor bone quality, adhesions, labral degeneration, and bone loss. Here, we outline our preferred surgical technique to restore glenohumeral stability using the Latarjet procedure for a patient with a postage stamp fracture.

A stabilizing role of the glenoid labrum: the suction cup effect

BACKGROUND

The glenoid labrum acts as a bumper, deepening glenoid concavity and amplifying the concavity-compression mechanism, and serves as the scapular attachment for glenohumeral ligaments. The role of the posterosuperior labrum in anteroinferior glenohumeral stability, and the role of the anterior labrum in posterior stability has been debated. The purpose of this study was to quantify the contribution of anteroinferior and posterosuperior labral tears to loss of glenohumeral stability in multiple directions.

METHODS

Fourteen fresh-frozen cadaveric shoulders were tested on a custom stability ratio measurement apparatus. The peak force that was required to translate the humeral head in anterior, anteroinferior, posterior, and posteroinferior directions was measured under 5 conditions: intact labrum (n = 14), anteroinferior labral tear (n = 7), posterosuperior labral tear (n = 7), combined labral tear (n = 14), and no labrum (n = 14). The stability ratio was defined as the peak translational force divided by the compressive force. Within force-translation curves, we defined the suction cup effect as the force required to release the negative pressure created by an intact labrum.

RESULTS

The suction cup effect was usually present with the intact labrum and always disappeared after removal of the labrum for anterior (100% vs. 0%) and posterior (86% vs. 0%) translations (P < .001). After creation of an anteroinferior labral tear, the stability ratio for posterior direction decreased (P < .001) and the suction cup effect disappeared (P < .001). After creation of a posterosuperior labral tear, stability ratios in the anterior and anteroinferior directions decreased (P ≤ .006) and the suction cup effect disappeared (P ≤ .015). The stability ratio for anterior and anteroinferior testing was more diminished by posterosuperior labral tears than anteroinferior labral tears, and the stability ratio for posterior testing was more diminished by anteroinferior labral tears than posterosuperior labral tears.

CONCLUSION

Anteroinferior labral tears decreased posterior stability and posterosuperior labral tears decreased anterior and anteroinferior stability, largely because of loss of the suction cup effect.

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

Background

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

Methods

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

Results

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

Conclusion

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

Navigation-Guided Trans-glenoid Flexible Fixation Technique for Arthroscopic Autologous Iliac Crest Grafting Treatment of Recurrent Shoulder Dislocation

Recurrent anterior shoulder dislocations accompanied by severe glenoid bone defects are typically treated with arthroscopy. Until now, autologous iliac grafting has been reported with excellent results, and different techniques of bone fixation have been introduced by numerous scholars. In this article, we introduce a specially designed guide that can achieve accurate positioning of the bone graft and a nonrigid graft fixation technique with a single EndoButton (Smith & Nephew). Using this technique, we greatly simplify the arthroscopic procedure and avoid the use of screws.

Effect of Anterior Glenoid Chondrolabral Defects on Anterior Glenohumeral Stability: A Biomechanical Study

Background:

It is well known that glenoid osseous defects >13.5% of the glenoid width critically destabilize the shoulder, as do labral tears. Chondrolabral defects often occur with anterior dislocation of the shoulder. It is unclear whether glenoid chondrolabral defects contribute to shoulder stability and, if so, at what size they become critical.

Purpose/Hypothesis:

The purpose of this study was to determine the effect of incremental chondrolabral defect sizes on anterior shoulder stability in the setting of labral deficiency. The hypothesis was that chondrolabral defects ≥13.5% of the glenoid width will decrease anterior shoulder stability.

Study Design:

Controlled laboratory study.

Methods:

This controlled laboratory study tested 12 fresh-frozen shoulders. Specimens were attached to a custom testing device in abduction and neutral rotation with 50-N compression applied to the glenoid. The humeral head was translated 10 mm anterior, anteroinferior, and anterosuperior with the conditions of intact cartilage and labrum and anterior full-thickness chondrolabral defects of 3-, 6-, and 9-mm width. Translation force was measured continuously. Peak translation force divided by 50-N compressive force defined the stability ratio. Data were analyzed using analysis of variance.

Results:

The anterior stability ratio decreased between the intact state (36% ± 7%) and all defects ≥3 mm (≤32% ± 8%; P ≤ .023). The anteroinferior stability ratio decreased between the intact state (52% ± 7%) and all defects ≥3 mm (≤47% ± 7%; P ≤ .006). The anterosuperior stability ratio decreased between the intact state (36% ± 4%) and all defects ≥6 mm (≤33% ± 4%; P ≤ .006). A 3-mm defect equated to 10% of the glenoid width. There were moderate to strong negative correlations between chondrolabral defect size and stability ratio in the anterior, anteroinferior, and anterosuperior directions (r = –0.79, –0.63, and –0.58, respectively; P ≤ .001). There were moderate to strong negative correlations between the percentage of glenoid chondrolabral defect size to the glenoid width and the stability percentage in all directions (r = –0.81, –0.63, and –0.61; P ≤ .001).

Conclusion:

An anterior glenoid chondrolabral defect ≥3 mm (>10% of the glenoid width) significantly decreased anterior and anteroinferior stability. Chondrolabral defect size negatively correlated with stability.

Clinical Relevance:

To fully restore glenohumeral stability, in addition to labral repair, it may be necessary to reconstruct chondrolabral defects as small as 3 mm (10% of the glenoid width).

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

Introduction

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

Objective

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

Methods

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

Results

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

Conclusion

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

Bankart Repair With Transferred Long Head of the Biceps Provides Better Biomechanical Effect Than Conjoined Tendon Transfer in Anterior Shoulder Instability With 20% Glenoid Defect

PURPOSE

To examine the biomechanical differences between labral repair with transferred conjoined tendon and transferred long head of the biceps tendon (LHBT) for anterior shoulder instability with 20% bone loss.

METHODS

Twelve cadaveric shoulders were tested in sequent 5 conditions: intact, 20% glenoid defect, Bankart repair, Bankart repair with transferred conjoined tendon (dynamic conjoined tendon sling, DCS), and with transferred LHBT (dynamic LHBT sling, DLS) at 60° of glenohumeral abduction and 60° of external rotation. The physiological glenohumeral joint load was created by forces applied to the rotator cuff, conjoined tendon, and LHBT. The glenohumeral compression force and range of motion were recorded before anteroinferior force application. The anterior, inferior, and total translations were measured with 20, 30, 40, and 50 N of anteroinferior force, respectively.

RESULTS

Anteroinferior glenoid defect led to significant increase of humerus translation and decrease of glenohumeral compression force. DLS provided better resistance effect in both anterior-posterior and superior-inferior directions than DCS under high loading condition (40 N, P =.03; 50 N, P <.01). Both DCS and DLS procedures could further restore glenohumeral compression force with Bankart repair (Bankart repair: 32.1 ± 4.0 N; DCS: 36.7 ± 3.2 N, P < .01; DLS: 35.8 ± 3.6 N, P =.03). No range of motion restrictions were observed relative to the normal shoulder.

CONCLUSIONS

Both the DLS and DCS techniques could reduce the anterior-inferior translation and partially restore the glenohumeral stability in anterior shoulder instability with 20% anteroinferior glenoid defect compared with Bankart repair. Under greater loading conditions, DLS provides better stability than DCS.

CLINICAL RELEVANCE

Shoulder stability can be restored by DLS and DCS with low load. With greater shoulder stability requirements, DLS might be a better option than DCS for anterior shoulder instability with 20% bone loss.

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

Background

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

Methods

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

Results

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

Conclusion

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

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

Level of evidence

Basic Science Study; Computer Modeling.

Biomechanical Testing of Scapular Spine Autograft for Anterior Glenoid Bone Augmentation

Background:

Augmentation of anterior glenoid defects with bone graft can improve shoulder stability and reduce the risk of redislocation. Several characteristics of the scapular spine may make it a suitable harvest site, avoiding the disadvantages associated with other glenoid augmentation procedures.

Purpose:

To evaluate the capacity of scapular spine autograft to restore the stabilizing joint-reaction forces of the shoulder in simulated scenarios of bony anterior shoulder instability.

Study Design:

Controlled laboratory study.

Methods:

We obtained 6 matched pairs of fresh-frozen cadaveric shoulders. Skin, subcutaneous tissues, and non–rotator cuff muscles were removed from the specimens, leaving intact the rotator cuff musculature and shoulder capsule. A customized testing device was used to translate the humerus 1 cm anteriorly on the glenoid under 25 N of axial compression force. The peak joint-reaction force of the glenohumeral joint was then measured under 3 conditions: (1) specimen with intact glenoid, (2) specimen after a bone defect measuring 25% of the maximal width of the glenoid was made in the anteroinferior glenoid, and (3) specimen after size-matched glenoid augmentation with a scapular spine tricortical autograft. The primary outcome was the change in peak joint-reaction forces between the defect state and augmented state.

Results:

One matched pair was removed from final analysis secondary to anatomic concerns that undermined the accuracy of test results. Among the 10 remaining specimens, all showed a significant decrease in peak joint-reaction force after the glenoid defect was created compared with the intact state (P < .001). All remaining specimens showed an increase in peak joint-reaction force in the augmented state compared with the defect state (P < .001). On average, the augmented state restored 81% of the peak reaction force of the glenohumeral joint compared with the intact state, a nonsignificant difference (P = .07).

Conclusion:

The study findings indicated that autograft harvested from the scapular spine increased the bony restraint to anterior shoulder dislocation in shoulders with glenoid bone loss.

Clinical Relevance:

The scapular spine is an alternative for bony augmentation of glenoid defects in shoulder instability.

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

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

A review of bone grafting techniques for glenoid reconstruction

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Arthroscopic Bony Bankart Repair Using Suture Suspension to Increase Bone Contact Area

Bony Bankart lesions are anteroinferior glenoid rim fractures associated with capsulolabral tears. Untreated bony Bankart lesion can cause recurrent dislocation. So, the large bony Bankart lesions should be treated by anatomical reduction and stabilization. This Technical Note describes an arthroscopic bony Bankart lesion repair using suture suspension to increase contact area to gain more contact area and tissue compression to maximize the stability of the repair.

Long-term effect of immobilization in external rotation after first-time shoulder dislocation: an average 18-year follow-up

BACKGROUND

Immobilization in external rotation (ER) after a first-time shoulder dislocation was introduced to reduce the risk of recurrence compared with immobilization in internal rotation (IR), but its efficacy remains controversial. The purpose of this study was to determine the long-term effect of immobilization in ER after a first-time shoulder dislocation.

METHODS

Between October 2000 and March 2004, 198 patients with a first-time anterior dislocation of the shoulder (average age 37) were randomly assigned to immobilization in ER (ER group = 104 shoulders) or IR (IR group = 94 shoulders) for 3 weeks. At an average 2-year follow-up, 159 patients (80.3%) were available for evaluation. In the current study, these 159 patients were further followed up and interviewed by telephone. The following items were evaluated: recurrent instability, apprehensive feeling, surgical intervention, limitation in the range of motion, return to sports, and the Single Assessment Numeric Evaluation (SANE) score.

RESULTS

The average follow-up period was 18.2 years (range, 16-20 years). Fifty-six patients were available for follow-up with the follow-up rate of 35%. The number of recurrent patients was 6 of 27 (22%) in the ER group and 6 of 29 (21%) in the IR group (P = .889). The number of surgically stabilized patients was 3 of 27 (11%) in the ER group and 10 of 29 (34%) in the IR group (P = .038). In total, the recurrence rate was 33% (9 of 27) in the ER group and 55% (16 of 29) in the IR group (P = .100). Adding the surgical cases and those with the SANE score ≤70% as failure cases, the failure rate in the ER group (26%) was significantly lower than that in the IR group (52%) (P = .048). Among those who survived without surgical intervention, there were no significant differences in apprehensive feeling, return to sports, limited range of motion, and the SANE score between the groups.

CONCLUSIONS

Immobilization in ER reduced the risk of surgical intervention compared with IR in the long term.

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

BACKGROUND

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

STUDY DESIGN

Controlled laboratory study.

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL RELEVANCE

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

How does anterior glenoid bone loss affect shoulder stability? A cadaveric analysis of glenoid concavity and bony shoulder stability ratio

BACKGROUND

Concavity compression is an important glenohumeral stabilizing factor, and recent studies have suggested that peripheral glenoid bone loss creates the most relevant change in stability. This study analyzed changes in the bony shoulder stability ratio (BSSR) with sequential anterior glenoid bone loss (0%-40% width) and with reconstructive bone graft procedures. The aim was to quantify the critical bone defect size that would significantly alter the BSSR and determine restoration of the BSSR with the Latarjet procedure.

METHODS

Anterior glenoid defects were created with sequential osteotomies (10%-40%), and defects were reconstructed using 2 Latarjet modifications (classic Latarjet procedure and congruent-arc Latarjet [CAL] procedure). We obtained 108 computed tomography scans of (1) intact scapulae (n = 12), (2) after each bone defect (n = 48), and (3) after each reconstruction (n = 48). The glenoid concavity depth and concavity radius were measured, and the BSSR was determined using a validated mathematical formula. Statistical analysis was performed to determine significant differences between the intact state and each of the deficient and reconstructed glenoids.

RESULTS

The glenoid concavity radius increased by approximately 30% (14 mm) and the glenoid concavity depth decreased by 50% (1.5 mm) from the 0% to 40% defect. The maximal sequential change in depth (1.2 mm, 44%; P < .001) and radius (6 mm, 12%; P < .001) occurred at the 10% glenoid defect. The overall BSSR decreased by approximately 40% (0.15) from the intact glenoid to the 40% defect. This change in the BSSR was most profound (0.11, 30%; P < .001) at the 10% glenoid defect and was only marginal thereafter between the 20% and 40% defects (0.24, 0.22, and 0.21). The Latarjet procedure adequately restored glenoid concavity; however, the CAL procedure significantly overcorrected all 3 parameters at 10% defect.

CONCLUSION

The glenoid concavity depth and BSSR undergo progressive deformation with sequential bone loss, and 90% of this change occurs with a 10% glenoid defect. Articular concavity and the BSSR are adequately restored with the Latarjet procedure, and the CAL procedure significantly overcorrects concavity in mild (0%-10%) defects.

Arthroscopy Limits on Anterior Shoulder Instability

Much is discussed about the limits of the treatment of anterior shoulder instability by arthroscopy. The advance in understanding the biomechanical repercussions of bipolar lesions on shoulder stability, as well as in the identification of factors related to the higher risk of recurrence have helped us to define, more accurately, the limits of arthroscopic repair. We emphasize the importance of differentiation between glenoid bone loss due to erosion (GBLE) and glenoid edge fractures, because the prognosis of treatment differs between these forms of glenoid bone failure. In this context, we understand that there are three types of bone failure: a) bone Bankart (fracture); b) combined; and c) glenoid bone loss due to anterior erosion (GBLE), and we will address the suggested treatment options in each situation. Until recently, the choice of surgical method was basically made by the degree of bone involvement. With the evolution of knowledge, the biomechanics of bipolar lesions and the concept of glenoid track , the cutoff point of critical injury, has been altered with a downward trend. In addition to bone failures or losses, other variables were added and made the decision more complex, but a little more objective. The present update article aims to make a brief review of the anatomy with the main lesions found in instability; to address important details in arthroscopic surgical technique, especially in complex cases, and to bring current evidence on the issues of greatest divergence, seeking to guide the surgeon in decision making.

Return to sport following Latarjet glenoid reconstruction for anterior shoulder instability

BACKGROUND

Latarjet coracoid transfer reconstruction is the gold standard for the treatment of recurrent shoulder instability with anterior-inferior glenoid bone loss, and return to sport is often a primary outcome of interest in this patient population. The purpose of this study was to determine the rate of return to sport in patients undergoing the Latarjet procedure and variables that are associated with a higher likelihood of a successful return to sport.

METHODS

A prospectively maintained institutional registry was retrospectively queried between August 2012 and August 2016 for all patients who underwent the Latarjet procedure. Patients were contacted electronically and via telephone to administer a previously validated and standardized return-to-sport survey. Patients self-reported return to sport, varying sports participation, recurrence of instability, and time to return to sport. Multivariate analysis was performed to determine variables associated with each outcome.

RESULTS

Of 83 patients, 66 (75.3%) were available for final follow-up, of whom 60 participated in sports prior to surgery and were eligible for inclusion. The average follow-up period was 53.8 ± 11.8 months. The average age at surgery was 26.7 ± 11.3 years, and the average body mass index was 26.2 ± 4.0 kg/m2. There were 54 patients (90%) who were able to return to sport at an average of 8.6 ± 4.1 months following surgery. In total, 36 patients (60%) were able to return to sport at the same level or a better level of intensity, 19 of 28 patients (67.9%) were able to return to throwing sports without difficulty, and 31 of 60 patients (51.7%) reported that their shoulder was a hindrance to some activity. An increased likelihood of returning to sport was associated with increased body mass index (P = .016), male sex (P = .028), and decreased humeral bone loss volume (P = .034). An increased likelihood of returning to sport at the same level or a better level of intensity was associated with reduced humeral bone loss volume (P = .026). Recurrent instability was associated with humeral bone loss (P = .038).

CONCLUSION

Although a large majority of patients were able to return to sport following the Latarjet procedure, some patients experienced limitation with throwing and return to sport at the preinjury level. Greater humeral bone loss was associated with inferior outcomes. These findings should be discussed with patients in the preoperative setting to manage expectations appropriately.

What Is the Most Reliable Method of Measuring Glenoid Bone Loss in Anterior Glenohumeral Instability? A Cadaveric Study Comparing Different Measurement Techniques for Glenoid Bone Loss

BACKGROUND

Preoperative quantification of bone loss has a significant effect on surgical decision making and patient outcomes. Various measurement techniques for calculating glenoid bone loss have been proposed in the literature. To date, no studies have directly compared measurement techniques to determine which technique, if any, is the most reliable.

PURPOSE/HYPOTHESIS

To identify the most consistent and accurate techniques for measuring glenoid bone loss in anterior glenohumeral instability. Our hypothesis was that linear measurement techniques would have lower consistency and accuracy than surface area and statistical shape model-based measurement techniques.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 6 fresh-frozen human shoulders, 3 incremental bone defects were sequentially created resulting in a total of 18 glenoid bone defect samples. Analysis was conducted using 2D and 3D computed tomography (CT) en face images. A total of 6 observers (3 experienced and 3 with less experience) measured the bone defect of all samples with Horos imaging software using 5 common methods. The methods included 2 linear techniques (Shaha, Griffith), 2 surface techniques (Barchilon, PICO), and 1 statistical shape model formula (Giles). Intraclass correlation (ICC) using a consistency model was used to determine consistency between observers for each of the measurement methods. Paired t tests were used to calculate the accuracy of each measurement technique relative to physical measurement.

RESULTS

For the more experienced observers, all methods indicated good consistency (ICC > 0.75; range, 0.75-0.88), except the Shaha method, which indicated moderate consistency (0.65 < ICC < 0.75; range, 0.65-0.74). Estimated consistency among the experienced observers was better for 2D than 3D images, although the differences were not significant (intervals contained 0). For less experienced observers, the Giles method in 2D had the highest estimated consistency (ICC, 0.88; 95% CI, 0.76-0.95), although Giles, Barchilon, Griffith, and PICO methods were not statistically different. Among less experienced observers, the 2D images using Barchilon and Giles methods had significantly higher consistency than the 3D images. Regarding accuracy, most of the methods statistically overestimated the actual physical measurements by a small amount (mean within 5%). The smallest bias was observed for the 2D Barchilon measurements, and the largest differences were observed for Giles and Griffith methods for both observer types.

CONCLUSION

Glenoid bone loss calculation presents variability depending on the measurement technique, with different consistencies and accuracies. We recommend use of the Barchilon method by surgeons who frequently measure glenoid bone loss, because this method presents the best combined consistency and accuracy. However, for surgeons who measure glenoid bone loss occasionally, the most consistent method is the Giles method, although an adjustment for the overestimation bias may be required.

CLINICAL RELEVANCE

The Barchilon method for measuring bone loss has the best combined consistency and accuracy for surgeons who frequently measure bone loss.

3D MRI of the Shoulder

Magnetic resonance imaging provides a comprehensive evaluation of the shoulder including the rotator cuff muscles and tendons, glenoid labrum, long head biceps tendon, and glenohumeral and acromioclavicular joint articulations. Most institutions use two-dimensional sequences acquired in all three imaging planes to accurately evaluate the many important structures of the shoulder. Recently, the addition of three-dimensional (3D) acquisitions with 3D reconstructions has become clinically feasible and helped improve our understanding of several important pathologic conditions, allowing us to provide added value for referring clinicians. This article briefly describes techniques used in 3D imaging of the shoulder and discusses applications of these techniques including measuring glenoid bone loss in anterior glenohumeral instability. We also review the literature on routine 3D imaging for the evaluation of common shoulder abnormalities as 3D imaging will likely become more common as imaging software continues to improve.

Current concepts in anterior glenohumeral instability: diagnosis and treatment

The glenohumeral joint is the most dislocated articulation, accounting for more than 50% of all joint dislocations. The reason behind shoulder instability should be investigated in detail for successful management, and the treatment plan should be individualized for all patients. Several classification systems have been proposed for glenohumeral instability. A physical exam is mandatory no matter what classification system is used. When treating patients with anterior shoulder instability, surgeons need to be aware of the critical size of the bone loss, which is commonly seen. The glenoid track concept was clinically adopted, and the measurement of the glenoid track for surgical decision-making is recommended. Detailed assessment of existing soft tissue injury to the labrum, capsule, glenohumeral ligaments, and rotator cuff is also mandatory as their presence influences the surgical outcome. Rehabilitation, arthroscopic repair techniques, open Bankart procedure, capsular plication, remplissage, Latarjet technique, iliac crest, and other bone grafts offer the surgeon different treatment options according to the type of patient and the lesions to be treated. Three-dimensional (3D) technologies can help to evaluate glenoid and humeral defects. Patient-specific guides are low-cost surgical instruments and can be used in shoulder instability surgery. 3D printing will undoubtedly become an essential tool to achieve the best results in glenohumeral instability surgery.