Recurrence in traumatic anterior shoulder dislocations increases the prevalence of Hill-Sachs and Bankart lesions: a systematic review and meta-analysis

[Mid-term effectiveness of modified arthroscopic suture button fixation Latarjet procedure for treatment of recurrent anterior shoulder dislocations]

Objective

To summarize mid-term effectiveness of modified arthroscopic suture button fixation Latarjet procedure for treatment of recurrent anterior shoulder dislocations.

Methods

Between January 2018 and October 2020, 30 patients with recurrent anterior shoulder dislocations were treated with modified arthroscopic suture button fixation Latarjet procedure. There were 19 males and 11 females with an average age of 27.3 years (range, 18-41 years). The shoulder dislocation occurred 3-7 times, with an average of 4.9 times. The time from the last dislocation to operation was 3-10 days, with an average of 4.1 days. Glenoid defects exceeded 20% in all cases. There were 27 cases of Hill-Sachs lesions. The joint pain and function were estimated by visual analogue scale (VAS) score, University of California, Los Angeles (UCLA) score, Rowe score, American Association for Shoulder and Elbow Surgery (ASES) score, Walch-Duplay score, and the range of external rotation at 0° and external rotation at 90° abduction of shoulder before operation and at 1 month, 6 months, and last follow-up. The X-ray film, CT scan and three-dimensional reconstruction were reviewed to observe the position, healing, and absorption of the coracoid graft, correction of glenoid defect, and joint degeneration.

Results

The operation time ranged from 51 to 79 minutes, with an average of 68.4 minutes. All incisions healed without complications such as nerve or blood vessel injury. All patients were followed up 36-60 months with an average of 44.6 months. The VAS score, UCLA score, Rowe score, ASES score, Walch-Duplay score, and the range of external rotation at 0° and external rotation at 90° abduction after operation significantly improved when compared with preoperative values ( P<0.05). All indicators further improved with time, and the differences between different time points after operation were significant ( P<0.05). Imaging review showed that the coracoid graft was located in the anteroinferior glenoid at 1 day after operation, and no occurrence of shoulder osteoarthritis was found during follow-up. The anatomical structure of the glenoid was normal, and no delayed healing or non-union of the coracoid graft occurred. At 20 months after operation, arthroscopic re-exploration was performed in 1 case due to fracutre caused by falling injury revealed the good shaping of the coracoid graft, smooth glenoid, and no bone resorption or osteoarthritis.

Conclusion

For recurrent anterior shoulder dislocations, the modified arthroscopic suture button fixation Latarjet procedure can obtain good recovery of shoulder function and low incidence of complications and has a good mid-term effectiveness.

Glenohumeral morphological predictors of recurrent shoulder instability following arthroscopic Bankart repair

PURPOSE

The purpose of this study was to evaluate glenohumeral morphological features on a magnetic resonance arthrogram (MRA) to determine risk factors for recurrence of anterior shoulder instability following arthroscopic Bankart repair (ABR).

METHODS

A retrospective review of patients who underwent ABR between 2012 and 2017 was performed to identify patients who had recurrence of instability following stabilisation (Group 1). These were pair-matched in a 2:1 ratio for age, gender and sport with a control (Group 2) who underwent ABR without recurrence. Preoperative MRAs were evaluated for risk factors for recurrence, with glenoid bone loss and Hill-Sachs lesions also measured. Multilinear and multilogistic regression models were used to evaluate factors affecting recurrence.

RESULTS

Overall, 72 patients were included in this study, including 48 patients without recurrence and 24 patients with recurrent instability. There was a significant difference between the two groups in mean glenoid bone loss (Group 1: 7.3% vs. Group 2: 5.7%, p < 0.0001) and the rate of off-track Hill-Sachs lesions (Group 1: 20.8% vs. Group 2: 0%, p = 0.0003). Of the variables analysed in logistic regression, increased glenoid anteversion (p = 0.02), acromioclavicular (AC) degeneration (p = 0.03) and increased Hill-Sachs width were associated with increased risk of failure. Increased chondral version (p = 0.01) and humeral head diameter in the anteriorposterior view were found to be protective and associated with a greater likelihood of success.

CONCLUSION

Glenoid anteversion was a risk factor for recurrent instability, whereas increased chondral version and humeral head diameter were associated with higher rates of success following ABR. Glenoid bone loss, presence of an off-track Hill-Sachs lesion, increased Hill-Sachs width and AC degeneration were also associated with failure. These findings should be used by surgeons to stratify risk for recurrence following ABR.

LEVEL OF EVIDENCE

Level III.

Lower Range of Recurrent Instability Rates Following Bankart Repair and Remplissage Compared to Isolated Bankart Repair in Patients With "Nonengaging/On-Track" Hill-Sachs Lesions and <20% Glenoid Bone Loss

PURPOSE

To compare recurrent instability and return-to-sport rates along with external rotation differences between on-track (nonengaging) Hill-Sachs lesion patients undergoing either an isolated Bankart repair (IBR) or a Bankart repair augmented with a remplissage procedure (B+R).

METHODS

A search was conducted using 3 databases (PubMed, EMBASE, CINAHL) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Only clinical comparative (level of evidence I-III) studies were considered for inclusion. Quality assessment was performed using the Methodological Index for Non-Randomized Studies criteria.

RESULTS

Six level of evidence III studies, totaling 537 patients (202 B+R and 335 IBR) were included for analysis. All patients had <20% glenoid bone loss and a nonengaging, on-track Hill-Sachs lesion. At a median final follow-up of 34.7 months, recurrent dislocation rates ranged from 0% to 7.7% and 3.5% to 30% in the B+R and IBR groups, respectively. Moreover, subjective instability and revision surgery rates presented lower ranges in the B+R upon comparison with the IBR cohort (0%-32% vs 5%-71.4% and 0%-5% vs 0%-35%, respectively). Furthermore, return to preinjury level of sports ranged from 64% to 100% in the remplissage-augmented group and 50% to 90% in the IBR cohort. Postoperative external rotation at side varied from 50° to 63° in the B+R and 55° to 63° in the IBR arm. Additional subgroup analysis revealed recurrent dislocation rates in athletes and patients with near-track Hill-Sachs lesions undergoing remplissage augmentation to be 0% to 5% and 2% to 47% while ranging from 8.8% to 30% and 9% to 66% for IBR patients, respectively.

CONCLUSIONS

Upon qualitative analysis, ranges of recurrent instability measures, including recurrent dislocation rates, are higher in patients undergoing IBR in comparison to B+R. Activity level influences outcomes as athletes were found to have a higher range of recurrent dislocation rates in the IBR group. The addition of remplissage showed a higher range of return-to-sport rates with comparable postoperative external rotation between groups.

LEVEL OF EVIDENCE

Level III, systematic review of Level III studies.

Demographics and Outcomes of Glenohumeral Dislocations in Individuals With Elevated Body Mass Index

INTRODUCTION

No specific study has investigated the characteristics and outcomes of anterior shoulder dislocations in morbidly obese individuals. The purpose of this study was to describe shoulder dislocations in patients with body mass index (BMI) greater than 40.

METHODS

A retrospective review was conducted to identify patients aged 18 years and older with a BMI ≥40 who presented with a shoulder dislocation in a single institution from 2000 to 2020. Dislocation patterns, associated injuries, treatment modalities, and associated complications were recorded.

RESULTS

A significant increase was noted in the number of patients with BMI greater than 40 presenting per year (r2 = -0.831, P < 0.01) over the past 20 years. A significant increase was noted in the average BMI per year in this population (r2 = 0.504, P = 0.028). Fifteen patients (19.5%) experienced at least one recurrent dislocation episode. Ten patients had a Bankart lesion that was associated with an elevated BMI (P = 0.04). Nine patients (11.7%) sustained an associated neurologic injury (no association with BMI).

CONCLUSIONS

Over time, there has been an increase in shoulder dislocations in morbidly obese individuals in the United States, alongside an overall increase in the average BMI of patients who present with shoulder dislocations.

Arthroscopic Bankart with remplissage results in lower rates of recurrent instability with similar range of motion compared to isolated arthroscopic Bankart for anterior glenohumeral instability: A systematic review and meta-analysis

PURPOSE

The addition of the remplissage procedure to an arthroscopic Bankart procedure has been shown to improve clinical outcomes, yet at the expense of potentially decreasing shoulder range of motion. The purpose of this study was to assess recurrent instability, range of motion, functional outcomes and rates of return to sport outcomes in patients undergoing an isolated arthroscopic Bankart repair compared to those undergoing arthroscopic Bankart repair in addition to the remplissage procedure.

METHODS

According to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines, a search was conducted using three databases (MEDLINE/OVID, EMBASE and PubMed). Retrieved studies were screened based on predefined inclusion and exclusion criteria for comparative studies. Data were extracted and meta-analysis performed using a random-effects model.

RESULTS

A total of 16 studies (13 level III studies, 2 level II studies and 1 level I) were included with a total of 507 and 704 patients in the Bankart plus remplissage and isolated Bankart repair groups, respectively. No studies reported glenoid bone loss of >20% with the least percentage of glenoid bone loss reported among studies being <1%. There was a significantly increased rate of recurrent dislocations (odds ratio [OR] = 4.22, 95% confidence interval [CI]: 2.380-7.48, p < 0.00001) and revision procedures (OR = 3.36, 95% CI: 1.52-7.41, p = 0.003) in the isolated Bankart repair group compared to the Bankart plus remplissage group. Additionally, there were no significant differences between groups in terms of external rotation at side (n.s.), in abduction (n.s.) or at forward flexion (n.s.) at final follow-up. Furthermore, return to preinjury level of sport favoured the Bankart plus remplissage group (OR = 0.54, 95% CI: 0.35-0.85, p = 0.007).

CONCLUSION

Patients undergoing arthroscopic Bankart plus remplissage for anterior shoulder instability have lower rates of recurrent instability, higher rates of return to sport, and no significant difference in range of motion at final follow-up when compared to an isolated arthroscopic Bankart repair. Further large, prospective studies are needed to further determine which patients and degree of bone loss would benefit most from augmentation with the remplissage procedure.

LEVEL OF EVIDENCE

Level III.

Current Evidence Regarding Shoulder Instability in the Paediatric and Adolescent Population

Paediatric and adolescent shoulder instability is caused by a unique combination of traumatic factors, ligamentous laxity, and pattern of muscle contractility. The multifactorial nature of its aetiology makes interpretation of the literature difficult as nomenclature is also highly variable. The purpose of this review is to summarize the existing literature and shed light on the nuances of paediatric and adolescent shoulder instability. The epidemiology, clinical features, imaging, and management of all forms of paediatric shoulder instability are presented. The main findings of this review are that structural abnormalities following a dislocation are uncommon in pre-pubertal paediatric patients. Young post-pubertal adolescents are at the highest risk of failure of non-operative management in the setting of traumatic instability with structural abnormality, and early stabilisation should be considered for these patients. Remplissage and the Latarjet procedure are safe treatment options for adolescents at high risk of recurrence, but the side-effect profile should be carefully considered. Patients who suffer from instability due to generalized ligamentous laxity benefit from a structured, long-term physiotherapy regimen, with surgery in the form of arthroscopic plication as a viable last resort. Those who suffer from a predominantly muscle patterning pathology do not benefit from surgery and require focus on regaining neuromuscular control.

Defining Critical Humeral Bone Loss: Inferior Craniocaudal Hill-Sachs Extension as Predictor of Recurrent Instability After Primary Arthroscopic Bankart Repair

BACKGROUND

The glenoid track concept for shoulder instability primarily describes the medial-lateral relationship between a Hill-Sachs lesion and the glenoid. However, the Hill-Sachs position in the craniocaudal dimension has not been thoroughly studied.

HYPOTHESIS

Hill-Sachs lesions with greater inferior extension are associated with increased risk of recurrent instability after primary arthroscopic Bankart repair.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

The authors performed a retrospective analysis of patients with on-track Hill-Sachs lesions who underwent primary arthroscopic Bankart repair (without remplissage) between 2007 and 2019 and had a minimum 2-year follow-up. Recurrent instability was defined as recurrent dislocation or subluxation after the index procedure. The craniocaudal position of the Hill-Sachs lesion was measured against the midhumeral axis on sagittal magnetic resonance imaging (MRI) using either a Hill-Sachs bisecting line through the humeral head center (sagittal midpoint angle [SMA], a measure of Hill-Sachs craniocaudal position) or a line tangent to the inferior Hill-Sachs edge (lower-edge angle [LEA], a measure of Hill-Sachs caudal extension). Univariate and multivariate regression were used to determine the predictive value of both SMA and LEA for recurrent instability.

RESULTS

In total, 176 patients were included with a mean age of 20.6 years, mean follow-up of 5.9 years, and contact sport participation of 69.3%. Of these patients, 42 (23.9%) experienced recurrent instability (30 dislocations, 12 subluxations) at a mean time of 1.7 years after surgery. Recurrent instability was found to be significantly associated with LEA >90° (ie, Hill-Sachs lesions extending below the humeral head equator), with an OR of 3.29 (P = .022). SMA predicted recurrent instability to a lesser degree (OR, 2.22; P = .052). Post hoc evaluation demonstrated that LEA >90° predicted recurrent dislocations (subset of recurrent instability) with an OR of 4.80 (P = .003). LEA and SMA were found to be collinear with Hill-Sachs interval and distance to dislocation, suggesting that greater LEA and SMA proportionally reflect lesion severity in both the craniocaudal and medial-lateral dimensions.

CONCLUSION

Inferior extension of an otherwise on-track Hill-Sachs lesion is a highly predictive risk factor for recurrent instability after primary arthroscopic Bankart repair. Evaluation of Hill-Sachs extension below the humeral equator (inferior equatorial extension) on sagittal MRI is a clinically facile screening tool for higher-risk lesions with subcritical glenoid bone loss. This threshold for critical humeral bone loss may inform surgical stratification for procedures such as remplissage or other approaches for at-risk on-track lesions.

Surgical Intervention Following a First Traumatic Anterior Shoulder Dislocation Is Worthy of Consideration

Up to 60% of patients experience recurrence after a first traumatic anterior shoulder dislocation (FTASD), which is often defined as having experienced either dislocation or subluxation. Thus surgical intervention after FTASD is worthy of consideration and is guided by the number of patients who need to receive surgical intervention to prevent 1 redislocation (i.e., number needed to treat), (subjective) health benefit, complication risk, and costs. Operative intervention through arthroscopic stabilization can be successful in reducing recurrence risk in FTASD, as has been shown in multiple randomized controlled trials. Nevertheless, there is a large "gray area" for the indication of arthroscopic stabilization, and it is therefore heavily debated which patients should receive operative treatment. Previous trials showed widely varying redislocation rates in both the intervention and control group, meta-analysis shows 2% to 19% after operative and 20% to 75% after nonoperative treatment, and redislocation rates may not correlate with patient-reported outcomes. The literature is quite heterogeneous, and a major confounder is time to follow-up. Furthermore, there is insufficient standardization of reporting of outcomes and no consensus on definition of risk factors. As a result, surgery is a reasonable intervention for FTASD patients, but in which patients it best prevents redislocation requires additional refinement.

IODA-shoulder®, a 3-dimensional automated software for glenoid bone loss quantification in shoulder instability. A validation study

BACKGROUND

Glenoid bone loss (GBL) calculation in patients with shoulder instability has a wide variability in methods and their reliability. The purpose of this study was to describe and validate a new semi-automated software developed to improve GBL calculation using a 3D imaging modeling (IODA-shoulder) and to compare the method to the PICO area method.

PATIENTS AND METHODS

A semi-automated software to assess GBL was preliminarily developed and validated on 7 fresh frozen specimens (scapulae with artificially created glenoid defect), using water displacement method. Afterwards, the software was retrospectively used on CT images of 20 patients affected by recurrent shoulder dislocation. Inclusion criteria were: unilateral dislocation, minimum 2 dislocation episodes. Exclusion criteria were bone reconstruction of the glenoid, failed shoulder stabilization, bilateral dislocation, shoulder arthritis. Three-dimensional computed tomography images of bilateral shoulder were retrieved for each patient. Two methods to determine GBL were compared. The PICO surface area method and the new IODA method. We assessed the intra- and inter-rater reliability of the two methods with the Intraclass Correlation Coefficient (ICC), the Bland-Alman analysis, and Lin's concordance correlation coefficient (CCC).

RESULTS

We did not find a statistically significant difference between the mean volumes calculated with PICO and IODA methods, respectively 914 vs. 815 mm3, p=0.155. The analysis carried out by using the traditional PICO method showed a lower concordance rate among four observers than the higher concordance found using IODA method, regardless of the size and the location of the defect. The ICC agreement with PICO was significantly lower than with IODA (0.76 vs. 0.97). We found a poor CCC with PICO (from 0.65 to 0.81) and a substantial one with IODA (from 0.96 to 0.98).

DISCUSSION

The intra- and inter-rater reliability using IODA method is significantly better than PICO method. The assessment of GBL using IODA method is time saving, avoiding significant inter- and intra-observer variation, mainly due to individual skill and experience in the method.

LEVEL OF EVIDENCE

IV, experimental study.

Does glenoid bone loss accompany posterior shoulder instability with only labral tear? A magnetic resonance imaging-based study

BACKGROUND

The primary aim of this study was to investigate bone loss in the glenoid with magnetic resonance imaging in posterior shoulder instability with only a labral tear.

METHODS

A total of 76 patients operated on because of posterior and anteroposterior shoulder instability only with a labral tear between 2006 and 2019 (n = 40 and n = 36, respectively) were included in this study. The instability type, a presence of an additional superior labrum anteroposterior (SLAP) lesion, the number of dislocations, and the magnetic resonance imaging-based measurements (the glenoid diameter and the bone defect size in the glenoid, the Hill-Sachs lesion [HSL] and the reverse HSL [rHSL] length, the angle and the arc length of HSL and rHSL, and the humerus head diameter and its area) were analyzed.

RESULTS

The size of the anterior glenoid defect, the rHSL measurements (length, angle, and arc length), and the ratio of the anterior glenoid defect size to the glenoid diameter were significantly higher for anteroposterior instability (P < .01) cases. There was no significant difference (P = .49, .64, and .82, respectively) for the presence of an additional SLAP pathology, the glenoid diameter, the posterior glenoid defect, and the ratio of the posterior glenoid defect size to the glenoid diameter in posterior and anteroposterior instability groups. The increased number of dislocations was associated with increased rHSL length and total arc length (P = .04 and .03, respectively). An additional SLAP lesion in posterior shoulder instabilities was not associated with the bone defect size (P = .29).

CONCLUSION

Although the posterior shoulder instability with only a labral tear is likely to cause a bone defect, we have shown that the instability is not expected to be caused by the bone defect. Therefore, this study points out that only soft tissue repair without considering the bone defect could be promising in this patient group.

Isolated Large Glenoid Fracture and Acute Glenohumeral Dislocation in Elderly Patients: A Case Series Treated Surgically With Reverse Shoulder Arthroplasty and Augmented Glenoid

Background

One of the most frequent complications in patients affected by traumatic anterior dislocations is bony Bankart lesion. This study evaluates the clinical and functional outcomes of 10 patients with isolated large glenoid fracture and acute glenohumeral dislocation treated with reverse shoulder arthroplasty.

Methods

Patients older than 69 years who underwent reverse shoulder arthroplasty after isolated large glenoid fracture and acute glenohumeral dislocation between 2016 and 2022 at the same institute were selected. Shoulder range of motion and pain level was assessed. The impact on quality of life has been evaluated through four measures: the constant scale, the simple shoulder test (SST), the OXFORD scale, and The University of California-Los Angeles (UCLA) shoulder scale.

Results

The mean Constant score was 77.1 (range 68-84), the mean SST score was 9.4 (range 8-10), the Oxford score was 44.3 (range 35-48), and the UCLA shoulder scale was 27.1 (range 24-30). No reoperation was performed on any patient in this series.

Conclusion

Reverse shoulder arthroplasty for elderly patients with bony Bankart lesion and acute glenohumeral dislocation represents a valuable option in terms of clinical results, patient satisfaction and early- to medium-term complications.

Atypical Shoulder Instability Patterns in Adolescents Following Traumatic Anterior Shoulder Dislocation

BACKGROUND

Traumatic anterior shoulder instability is common in the adolescent athlete, and when it is untreated, the recurrence rate is high. Atypical lesions-such as anterior glenoid periosteal sleeve, humeral glenohumeral ligament, and insertional tendon avulsions-may occur within this population, and accurate diagnosis and appropriate lesion management are key to treatment success.

PURPOSE

To evaluate the age, skeletal immaturity, bone loss, and uncommon soft tissue lesions as correlates of posttraumatic anterior shoulder instability lesion patterns in an adolescent population.

STUDY DESIGN

Cross-sectional study, Level of evidence, 3.

METHODS

Consecutive patients ≤18 years of age (160 shoulders) treated within a single institution for traumatic anterior shoulder instability between June 2013 and June 2021 were reviewed. Demographics, injury mechanism, radiographic and magnetic resonance imaging of lesions, the presence of any bone loss, operative findings, and physeal status were recorded. An overall 131 shoulders met the inclusion criteria. Instability lesion type was analyzed categorically by age <15 or ≥15 years; individual age was assessed for correlation with any bone loss present. Atypical lesions-anterior labral periosteal sleeve avulsion, humeral avulsion of the glenohumeral ligament, subscapularis avulsion-were assessed for correlations with age, open physeal status, and the presence of any bone loss.

RESULTS

An overall 131 shoulders (mean, 15.3 years; range, 10.5-18.3) were identified for this study: 55 in patients <15 years old and 76 in patients ≥15 years old. Bony injuries such as Bankart and Hill-Sachs lesions were more common in the ≥15-year-old group (P = .044 and P = .024, respectively). Bony Bankart injuries were found at a rate of 18.2% in the <15-year-old group, as compared with 34.2% in the ≥15-year-old group (P < .05). Anterior labral periosteal sleeve avulsions were more common in the <15-year-old group (n = 13 [23.6%] vs n = 8 [10.5%]; P < .044), as were all atypical lesions combined (n = 23 [41.8%] vs n = 13 [17.1%]; P < .0018].

CONCLUSION

In this series of anterior shoulder instability in children and adolescents, instability lesions varied significantly by age. Bone loss was associated with older age at presentation, and atypical lesions were more common in patients <15 years of age. Treatment teams should be aware of less common soft tissue injuries in this young age group and ensure careful review of adequate imaging for proper diagnosis and treatment in these younger patients.

"Nearly off-track lesions" or a short distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track does not seem to be accurate in predicting recurrence after an arthroscopic Bankart repair in a military population: a case-control study

BACKGROUND

On-track lesions with a short distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track (nearly off-track) may predispose recurrence after arthroscopic Bankart repair (ABR) in the general population. The aim of this study was to determine if a shorter distance between the medial edge of the Hill-Sachs lesion and the medial edge of the glenoid track could accurately predict recurrence after an ABR in a high-demand military population. It was hypothesized that a shorter distance would not accurately predict recurrence.

MATERIALS AND METHODS

A retrospective monocenter case-control study was performed at the Dutch Central Military Hospital. Patients with an on-track Hill-Sachs lesion who underwent a primary ABR between 2014 and 2019 with a minimal follow-up of 2 years and a preoperative magnetic resonance imaging (MRI) assessment received a questionnaire. The primary outcome was recurrence, defined as a complete dislocation or subluxation. Glenoid bone loss was assessed using a linear-based method on MRI. The distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track was defined as the distance to dislocation (DTD). A receiver operating characteristic curve was created to determine the predictive value of the DTD for recurrence. Logistic regression was used to determine preoperative risk factors that predispose recurrence. Covariates were selected based on univariable analysis and included gender, body mass index, age at surgery and first dislocation, laterality, smoking habits, overhead shoulder activity during work, preoperative dislocations, sports type and level, bony or labral lesions on MRI, and DTD.

RESULTS

In total, 80 patients with an average follow-up of 4.8 ± 1.9 years completed the questionnaire and were included in the analyses. Seventeen patients (21%) experienced recurrence at the final follow-up. No difference in DTD was observed among patients who experienced recurrence (9 ± 4 mm) compared with patients who did not (9 ± 5 mm; P = .81). The receiver operating characteristic curve demonstrated no predictive power of DTD for recurrence (area under the curve = 0.49). Smoking at the time of surgery (odds ratio: 3.9; confidence interval: 1.2-12.7; P = .02) and overhead shoulder movement during work (odds ratio: 9.3; confidence interval: 1.1-78.0; P = .04) were associated with recurrence according to the logistic regression analysis.

CONCLUSION

A shorter DTD demonstrated no accuracy in predicting recurrence in a military population. Smoking at the time of surgery and overhead shoulder activity during work were associated with recurrence; however, these analyses were underpowered to draw valid conclusions.

High resorption rates following glenoid augmentation procedures do not seem to lead to higher recurrence rates or worse clinical outcomes: a systematic review and meta-analysis

PURPOSE

Bone augmentation techniques show a relatively high complication rate, which might be due to graft non-union and resorption. It is unclear which augmentation techniques demonstrate the highest amount of non-union and resorption and whether this leads to worse clinical or functional outcomes. Therefore, the aim of this review was (i) to compare non-union and resorption rates between surgical approaches, procedures, graft types, donor sites and fixation methods regarding clinical and functional outcomes and (ii) determine whether high non-union or resorption rates lead to less favorable clinical or functional outcomes.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statements were followed. PubMed, EMBASE (Ovid) and Cochrane Library were searched on December 15th 2021 for studies examining bone graft non-union or resorption using radiograph or CT following glenoid augmentation to treat anterior shoulder dislocation.

RESULTS

The search resulted in 103 inclusions, comprising 5,128 glenoid augmentations. When comparing pooled proportions of bony union, graft fracture rate, hardware failure rate, recurrence rate, return to sports and Rowe score, most results were similar between approaches, procedures, graft types, donor sites and fixation methods. High resorption rates were seen for allograft augmentation (74.3; 95% CI: 39.8-92.7) compared to autograft augmentation (15.5; 95% CI 10.1-23.2), but this was not associated with higher recurrence rates or worse clinical outcomes. Meta-analyses (8 studies; 494 patients) demonstrated no difference in incomplete and complete non-union rates between arthroscopic and open procedures; however, both analyses showed substantial heterogeneity. Higher partial resorption rates were observed on CT (48.0; 95% CI 43.3-52.7) compared to radiograph (14.1; 95% CI 10.9-18.1). Three studies comprising 267 shoulders demonstrated a higher rate of non-union and recurrence in smokers, whereas one study comprising 38 shoulders did not.

CONCLUSION

Non-union and resorption rates were similar among procedures, grafts and fixation methods. Higher resorption rates were observed in allografts, but this was not associated with higher recurrence rates or worse clinical outcomes. Pooling data demonstrated substantial heterogeneity and definitions varied among studies, warranting more standardized measuring.

LEVEL OF EVIDENCE

IV.

Increased superior translation following multiple simulated anterior dislocations of the shoulder

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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