Analysis of risk factors for glenoid bone defect in anterior shoulder instability

Association of Instability History and Off-Track Hill-Sachs Lesions in Anterior Shoulder Instability

Background

The glenoid track concept is now widely accepted, and its evaluation is considered essential for making decisions about surgery.

Purpose

To define preoperative descriptive data and clinical and functional features in patients with anterior glenohumeral instability according to glenoid track status and to analyze the influence of off-track Hill-Sachs (HS) lesions on preoperative shoulder function.

Study Design

Case-control study; Level of evidence, 3.

Methods

Preoperative magnetic resonance imaging or computed tomography scans were used to measure the glenoid track. Descriptive data and preoperative objective and subjective clinical and functional features were compared between patients with on-track HS lesions versus off-track HS lesions. Multivariate regression analysis was conducted to identify potential risk factors for off-track HS lesion development.

Results

A total of 235 patients (201 men, 34 women; mean age, 29.6 ± 8.6 years) were included- 134 shoulders (57%) with on-track HS lesions and 101 shoulders (43%) with off-track HS lesions. Age <20 years at first dislocation, number of dislocations, and ≥2 years between first dislocation and surgery were significantly different between the study groups (P = .005, P = .0001, and P = .01, respectively). Regarding these characteristics, the odds ratios for the risk of developing an off-track lesion were 2.67 (95% CI, 1.2-5.99)-1.2 times higher for each additional instability episode (95% CI, 1.025-1.14) and 2.42 times higher (95% CI, 1.176-4.608) for patients whose first dislocation was ≥2 years before surgery, respectively. Patients with off-track HS lesions had a significantly greater degree of instability (P = .04), worse Rowe scores (48.8 ± 15.3 vs 54.8 ± 28.3 for on-track HS lesions; P = .04), and lower Western Ontario Shoulder Instability scores (975 ± 454 vs 1179 ± 428 for on-track HS lesions; P = .01).

Conclusion

Characteristics related to a history of instability (age <20 years at first instability episode, larger number of dislocations, ≥2 years between first dislocation and surgery) were found to be risk factors for the development of an off-track HS lesion in this study. Off-track lesions led to a higher degree of instability and worse objective and subjective preoperative shoulder function versus on-track HS lesions.

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

Background

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

Purpose

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

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

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

Results

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

Conclusion

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

Arthroscopic Xenograft With Cerclage Fixation: A Method for Glenoid Bone Loss Reconstruction With Cerclage Fixation Using a Specific Posterior Guide

Large glenoid bone defects are closely associated with high failure rates after arthroscopic Bankart repair in chronic anterior shoulder instability; therefore nowadays the glenoid bone grafting reconstruction procedure is strictly recommended. On the contrary, the optimal grafting procedure is still controversial because there is considerable concern about the resorption rate of allografts, donor site morbidity of the autografts, and sequelae caused by the use of metal fixation devices in proximity of the shoulder joint. We describe an all-arthroscopic technique for anatomic reconstruction of the glenoid that uses a previously shaped xenograft assembled with a metal-free fixation device using 2 ultra-high-strength sutures (FiberTape Cerclage System; Arthrex, Naples, FL), using a specific posterior guide (Arthrex, Naples, FL) in combination with upper third subscapularis augmentation.

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.

Risk of Upper Extremity Musculoskeletal Injury Within the First Year After a Concussion

Background

Emerging evidence suggests that athletes and military personnel are at increased risk for lower extremity musculoskeletal injury after a concussion; however, the association between concussion and subsequent upper extremity (UE) musculoskeletal injury is unknown.

Purpose

To prospectively examine the association between concussion and UE musculoskeletal injury risk within the first year after returning to unrestricted activity.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 316 cases of concussion 42% (132/316 women) were observed among 5660 Concussion Assessment, Research and Education Consortium participants at the United States Military Academy from May 2015 to June 2018. Active injury surveillance within the cohort was conducted for 12 months after unrestricted return to activity to identify any incident cases of acute UE musculoskeletal injury. Injury surveillance during the follow-up period was also conducted for nonconcussed controls who were matched by sex and competitive sport level. Univariate and multivariable Cox proportional hazards regression models were used to estimate hazard ratios between concussed cases and nonconcussed controls for time to UE musculoskeletal injury.

Results

During the surveillance period, 19.3% of concussed cases and 9.2% of nonconcussed controls sustained a UE injury. In the univariate model, concussed cases were 2.25 times (95% CI, 1.45-3.51) more likely to sustain a UE injury during the 12-month follow-up period when compared with the nonconcussed controls. In the multivariable model, adjusted for history of concussion, sport level, somatization, and history of UE injury, concussed cases were 1.84 times (95% CI, 1.10-3.07) more likely to sustain a UE injury during the surveillance period compared with nonconcussed controls. Sport level remained an independent risk factor for UE musculoskeletal injury; however, concussion history, somatization, and history of UE injury were not independent risk factors.

Conclusion

Concussed cases were more than twice as likely to sustain an acute UE musculoskeletal injury within the first 12 months after unrestricted return to activity when compared with nonconcussed controls. The higher hazard of injury remained in the concussed group after adjusting for other potential risk factors.

Arthroscopic Bankart Repair for Adolescent Anterior Shoulder Instability: Clinical and Imaging Predictors of Revision Surgery and Recurrent Subjective Instability

BACKGROUND

Multiple clinical and radiologic risk factors for recurrent instability after arthroscopic Bankart repair have been described. Humeral bone loss has gained more recent attention, particularly with respect to "off-track" lesions and increased rates of recurrent instability and revision surgery.

PURPOSE

To evaluate clinical and radiologic predictors of failure after arthroscopic Bankart repair in adolescents.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A single-institution retrospective study was performed in patients <19 years of age treated with arthroscopic Bankart repair from 2011 to 2017. Magnetic resonance imaging measurements of glenoid and humeral bone loss, the glenoid track, and the presence of off-track Hill-Sachs (HS) lesions were assessed. All patients had a minimum follow-up of 24 months and completed patient-reported outcome scores. Failure was defined as revision surgery or postoperative subjective instability.

RESULTS

A total of 59 patients (46 male, 13 female) with a median age of 16 years (range, 12-18 years) were included. Ten patients (17%) had revision surgery and 8 patients (14%) had subjective instability without revision surgery. No clinical or radiologic factors were significantly different between the failure cohort and the nonfailure cohort. Four patients (7%) measured off-track, and 2 of these patients experienced failure. A total of 38 patients (64%) were identified to have an HS defect. Subgroup analysis of these patients identified a greater HS interval (HSI) in patients who underwent revision surgery as compared with those patients who did not have revision surgery. Among patients with GT ratio ≥15 mm, there was a 50% rate of revision surgery. The Pediatric/Adolescent Shoulder Survey (PASS) and Single Assessment Numeric Evaluation (SANE) scores at the final follow-up were not significantly different among patients with or without revision surgery. However, those with subjective instability who had not undergone revision surgery had significantly lower PASS and SANE scores as compared with the remainder of the cohort.

CONCLUSION

Of the adolescents in this cohort, 31% either had revision surgery (17%) or reported subjective feelings of instability (14%) after arthroscopic Bankart repair. Off-track instability was identified in 7% of the cohort but was not predictive of failure. Among the subgroup of patients with an HS defect, those who underwent revision surgery had a significantly larger HSI.

Ultrasound Assessment of Anterior Humeral Head Translation in Patients With Anterior Shoulder Instability: Correlation With Demographic, Radiographic, and Clinical Data

Background:

Ultrasonography can be used to quantitatively assess anterior humeral head translation (AHHT) at different degrees of shoulder abduction. Risk factors for recurrent shoulder instability have been identified.

Hypothesis:

It was hypothesized that the number of dislocations or glenoid or humeral bone loss would be associated with more AHHT as measured using ultrasound.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 39 patients who underwent surgery for anterior shoulder instability were prospectively studied. Ultrasound assessment of AHHT was performed immediately after general anesthesia was induced. The upper arm was placed at 0°, 45°, and 90° of abduction, and a 40-N anterior force was applied to the proximal third of the arm. The distance from the posterior edge of the glenoid to that of the humeral head was measured at each abduction angle using ultrasound with and without a 40-N anterior force, and the AHHT was calculated. The differences in translation at each shoulder angle were compared. Additionally, the authors investigated the association between AHHT and demographic, radiographic, and clinical data.

Results:

Compared with the AHHT at 0° of abduction (5.29 mm), translation was significantly larger at 45° of abduction (8.90 mm; P < .01) and 90° of abduction (9.46 mm; P < .01). The mean translation was significantly larger in female patients than in male patients at all degrees of abduction (P ≤ .036 for all). There was no correlation between AHHT at any abduction angle and number of dislocations, clinical data, or radiographic data (including bone loss).

Conclusion:

Ultrasound assessment of AHHT showed larger amounts of laxity at 45° and 90° than at 0° of abduction. Anterior glenohumeral laxity was greater in female than male patients. Glenoid or humeral bone loss did not correlate with AHHT, thereby clarifying that bone loss has no direct effect on measurements of capsular laxity in neutral rotation.

Concomitant Glenolabral Articular Disruption (GLAD) Lesion is Not Associated With Inferior Clinical Outcomes After Arthroscopic Bankart Repair for Shoulder Instability: A Retrospective Comparative Study

Purpose

The purpose of this study was to compare outcomes between anterior shoulder instability patients with and without glenolabral articular disruption (GLAD) lesions after undergoing arthroscopic Bankart repair and to evaluate potential risk factors for inferior outcomes and recurrent instability.

Methods

Prospectively collected data were retrospectively reviewed for patients who underwent arthroscopic Bankart repair with and without GLAD lesions at a minimum of 2 years follow-up. Consecutive patients were matched by age, sex, and number of anchors. Patient-reported outcomes (PROs) were evaluated before and after surgery, including American Shoulder and Elbow Surgeons, Single Assessment Numeric Evaluation, Quick Disabilities of the Arm, Shoulder and Hand, Short Form-12 score, and satisfaction. Recurrent dislocation, subjective instability, and reoperation were analyzed. Additionally, PROs were assessed on the basis of GLAD lesion characteristics.

Results

A total of 54 patients (27 GLAD, 27 control) with a mean age of 28.9 ± 11.6 years were analyzed at mean 4.5 ± 1.9 years (range, 2-9 years) follow-up. Thirty-eight (70.3%) of the participants were male. Patients in both groups experienced significant improvements in all PROs (P ≤ .006 for all measures) and reported high median satisfaction (scale 1-10: 10 vs 10, P = .290) at final follow-up. Two patients in the GLAD cohort and 1 in the control cohort underwent reoperation (P = .588). Four (14.8%) patients in each group reported recurrent dislocation (P = 1.0). Additionally, 2 (7.4%) GLAD patients and 1 (3.7%) control patient reported subjective shoulder instability after surgery (P = 1.0). No significant differences in PROs were observed based on anchor/labral advancement or treatment with microfracture, nor were significant correlations observed between GLAD lesion size and PROs (P > .05 for all).

Conclusion

Arthroscopic Bankart repair in patients with GLAD lesions resulted in significantly improved outcomes with high satisfaction, which was no different when compared with those without GLAD lesions.

Level of Evidence

Level III, retrospective comparative study.

The relationship of glenoid version and severity of glenoid bone loss in anterior shoulder instability patients: A retrospective cohort study

Background/objective

The effect of glenoid version on the severity of glenoid bone loss is not completely understood, although the variation of glenoid version angles is considered to reflect the degree of glenoid bone loss in anterior shoulder instability cases. The objective of this retrospective case-control study is to determine the relationship of the glenoid version and the severity of glenoid bone loss in a group of previously documented recurrent anterior shoulder dislocation patients.

Methods

We retrospectively collected magnetic resonance arthrogram (MRA) data from 72 patients with unidirectional recurrent anterior shoulder instability. The best-fit circle method was used to identify the percentage of glenoid bone loss. Measurements of glenoid labral, chondral, and bony versions were performed using the Friedman method.

Results

Using univariate regression analysis, it was found that a retroversion angle of more than 4 degrees was associated with an increased risk ratio for the occurrence of a critical glenoid defect by approximately 5 times.

Conclusions

24 Univariate logistic regression analysis, used to determine the presence of a critical glenoid bone defect, showed that both the bony version angle and the number of previous dislocations were significantly associated with the extent of glenoid bone loss. A retroversion angle of more than 4 degrees was associated with an approximately five-fold increase in the odds ratio for the presence of a critical glenoid defect. Surgeons may use the value of the measured glenoid version in prediction the required version of the reconstructive treatment.

Outcomes of Arthroscopic Latarjet Procedure for Anterior Glenohumeral Instability in Patients With Epilepsy: A Case-Control Study

BACKGROUND

Unacceptably high rates of redislocation, reoperation, osteoarthritis, and coracoid nonunion have been reported in patients with a seizure disorder after surgery for shoulder instabilitiy.

PURPOSE

To evaluate the objective and subjective functional and radiologic results of the arthroscopic Latarjet procedure for anterior shoulder instability in patients with epilepsy and compare them with the results of patients without epilepsy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective and comparative case-control analysis of patients operated for shoulder instability with arthroscopic Latarjet was conducted. Nineteen patients (21 unstable shoulders) with a seizure disorder (epilepsy group) were matched with 21 patients without a history of seizure (control group). Demographics, surgical indications, and imaging data were collected. Clinical outcomes at a minimum 2 years of follow-up (range, 2-9 years) postoperatively included Rowe score, Western Ontario Shoulder Instability Index (WOSI), Constant-Murley Shoulder Outcome (CMSO) score, and Single Assessment Numeric Evaluation (SANE). The incidence of complications, recurrent instability, redislocation, revision surgery, repeated seizure(s), and presence of osteoarthritis, coracoid nonunion, and osteolysis were also examined.

RESULTS

After a mean follow-up of 4.5 years, no significant differences in functional results were found between patients with and without epilepsy on the average Rowe (P = .917), WOSI (P = .621), CMSO (P = .600), and SANE (P = .859) scores. A total of 5 patients (7 shoulders) continued to have seizures postoperatively, but no seizure-related glenohumeral instability was documented. One dislocation and 1 subluxation were documented while participating in sports in each study group, comprising a recurrence rate of 9.5%, but no significant differences were found at comparison (P = .605). A bone defect did not influence the results, as no significant difference was found between the 2 groups. Osteoarthritic changes of the glenohumeral joint were observed in 5 shoulders (23.8%) in the epilepsy group and in 3 (14.3%) in the control group (P = .451). No case of coracoid nonunion or osteolysis was recorded. There was no statistically significant difference in postoperative athletic activity (P = .660). However, patients with epilepsy had significantly lower pre- and postoperative sports participation (P < .001).

CONCLUSION

Arthroscopic Latarjet stabilization can lead to improved functional and subjective outcomes and should be considered in patients with epilepsy with recurrent anterior glenohumeral instability. These results can be achieved regardless of the presence of bone defect and the postoperative control of seizures and are similar to those in patients without epilepsy.

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.

[Research progress on the relationship between shoulder instability and superior labrum anterior posterior lesion]

OBJECTIVE

To summarize the relationship between shoulder instability and superior labrum anterior posterior (SLAP) lesion.

METHODS

The characteristics of shoulder instability and SLAP lesion were analyzed, and the relationship between them in pathogenesis, clinical symptoms, and biomechanics was discussed by referring to relevant domestic and foreign literature.

RESULTS

Shoulder instability and SLAP lesion can occur both spontaneously and respectively. SLAP lesion destroys the superior labrum integrity and the long head of biceps tendon (LHBT) insertion, causing excessive humeral head displacement against glenoid, and leading to shoulder instability. While chronic repetitive or acute high-energy traumatic shoulder instability can in turn aggravate SLAP lesion, resulting in expansion and increased degree of the original lesion.

CONCLUSION

SLAP lesion destroys mechanisms of shoulder stability, while shoulder instability causes tears of the upper labrum and the LHBT, showing a connection between shoulder instability and SLAP lesion. However, the existing evidence can only demonstrate that shoulder instability and SLAP lesion induce and promote the development of each other, instead of a necessary and sufficient condition. Therefore, the specific causal relationship between the two remains unknown and needs to be further studied.

Instability and results after non-operative treatment of large anterior glenoid rim fractures: is there a correlation between fragment size or displacement and recurrence?

INTRODUCTION

There is little data available on non-operative treatment of anterior glenoid rim fractures (GRF). Nothing is known about fracture size and displacement in comparison to clinical outcomes and instability in a mainly middle-aged patient population. The aim of this study was to demonstrate the results of non-operative treatment in anterior glenoid rim fractures with the special focus on potential instability/recurrence.

METHODS

The inclusion criteria were non-operatively treated anterior GRF of at least ≥ 5 mm width using the age- and gender-matched Constant/Murley score (a.-/g.-CMS) and the Western Ontario Instability Index (WOSI). Radiographic parameters (fracture morphology, displacement, major tuberosity fractures and Hill-Sachs lesion using initial CT and radiographs) and the proportion of the fractured glenoid were detected (2D-CT-circle-method) and osteoarthritis (A.P. and axial radiographs) was classified according to Samilson/Prieto. Proportion of fractured glenoid and medial displacement were correlated with the recurrence rate and the clinical scores.

RESULTS

N = 36 patients could be followed-up after a mean of 4.4 years [12-140 month, average age: 58 (± 13, 33-86) years]. The a.-/g.-CMS was 93 (± 11, 61-100) points, and the WOSI was 81% (± 22%, 35-100%) on average. The mean intraarticular displacement was 4 mm (± 3 mm; 0-14 mm). The 2D-circle-method showed a mean glenoid fracture involvement of 21% (± 11, 10-52%). Two cases of frozen shoulders and one case with biceps pathology were associated with the trauma. Within the followed-up patient group re-instability has occurred in n = 2 patients (6%) within the first two weeks after trauma. Osteoarthritis was found in n = 11 cases. There was no correlation between the scores and the fracture size/displacement [(a.-/g.-CMS vs. displacement: r = - 0.08; p = 0.6; vs. size: r = - 0.29; p = 0.2); (WOSI vs. displacement: r = - 0.14; p = 0.4; vs. size: r = - 0.37; p = 0.06)], but very large (≥ 21%) fractures with displacement ≥ 4 mm showed slightly worse results without significant difference (a.-/g.-CMS p = 0.2; WOSI p = 0.2). The apprehension test was negative in all patients at final follow-up.

CONCLUSION

Non-operative treatment of anterior GRF was associated with overall good results within a mainly middle-aged larger patient group. Re-instability is rare and is not associated with fragment size but can occur in the first weeks after trauma. Size and dislocation of the fracture is not a criterion for the prognosis of potential instability.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Neuroplasticity Caused by Peripheral Proprioceptive Deficits

PURPOSE

Proprioceptive feedback is crucial for motor control and stabilization of the shoulder joint in everyday life and sports. Shoulder dislocation causes anatomical and proprioceptive feedback damage that contributes to subsequent dislocations. Previous recurrent anterior shoulder instability (RSI) studies did not investigate functional neuroplasticity related to proprioception of the injured shoulder. Thus, we aimed to study the differences in neuroplasticity related to motor control between patients with RSI and healthy individuals, using functional magnetic resonance imaging, and assess the effects of peripheral proprioceptive deficits due to RSI on CNS activity.

METHODS

Using passive shoulder motion and voluntary shoulder muscles contraction tasks, we compared the CNS correlates of proprioceptive activity between patients having RSI (n = 13) and healthy controls (n = 12) to clarify RSI pathophysiology and the effects of RSI-related peripheral proprioceptive deficits on CNS activity.

RESULTS

Decreased proprioception-related brain activity indicated a deficient passive proprioception in patients with RSI (P < 0.05 family-wise error, cluster level). Proprioceptive afferent-related right cerebellar activity significantly negatively correlated with the extent of shoulder damage (P = 0.001, r = -0.79). Functional magnetic resonance imaging demonstrated abnormal motor control in the CNS during voluntary shoulder muscles contraction.

CONCLUSION

Our integrated analysis of peripheral anatomical information and brain activity during motion tasks can be used to investigate other orthopedic diseases.

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.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Limited Predictive Value of the Instability Severity Index Score: Evaluation of 217 Consecutive Cases of Recurrent Anterior Shoulder Instability

PURPOSE

To review the existing variables and their ability to predict recurrence of shoulder instability as it relates to the Instability Severity Index Score (ISIS), as well as evaluate any other pertinent imaging and patient history variables that may impact risk of recurrent anterior instability after arthroscopic Bankart repair.

METHODS

All consecutive patients with recurrent anterior shoulder instability and who had arthroscopic instability repair were identified. Exclusion criteria were prior surgery on the shoulder, posterior or multidirectional instability, instability caused by seizure disorder, or a rotator cuff tear. All ISIS variables were recorded (age <20 years, sport type and level, hyperlaxity, Hill-Sachs on anteroposterior external rotation radiograph, loss of glenoid contour on anteroposterior radiograph), as well as additional variables: (1) number of instability events; (2) total time of instability; (3) glenoid bone loss (GBL) percent; and (4) Hill-Sachs measures (H/L/W/D/Volume). Postoperative outcomes were assessed based on the Western Ontario Shoulder Instability Index (WOSI), Single Assessment Numeric Evaluation (SANE) scores, and American Shoulder and Elbow Surgeons (ASES) scores, and recurrent anterior instability. Regression analysis was used to determine preoperative variables that predicted outcomes and failures.

RESULTS

There were 217 consecutive patients (209 male patients [96.5%], 8 female patients [3.5%]) who met the inclusion criteria and were all treated with a primary arthroscopic shoulder stabilization during a 3.5-year period (2007-2011), with a mean follow-up time of 42 months (range, 26-58). The mean age at first instability event was 23.9 years (range, 16-48 years) and the mean cumulative ISIS score for the overall group was 3.6 (range, 1-6). Outcomes were improved from mean preoperative (WOSI = 1,050/2,100; ASES = 61.0; SANE = 52.5) to postoperative (WOSI = 305/2,100; ASES = 93.5; SANE = 95.5). A total of 11.5% (25/217) of patients had evidence of recurrent instability (subluxation or dislocation). Additionally, all 25 patients who failed postoperatively also had consistently inferior ASES, SANE, and WOSI outcome scores when compared with successfully treated patients. Factors associated with failure were GBL greater than 14.5% (P < .001), total time of instability symptoms greater than 3 months (P = .03), Hill-Sachs volume greater than 1.3 cm³ (P = .02), contact sports participation (P = .05), and age 20 years or younger (P < .01). There was no correlation in outcomes with Hill-Sachs on presence of glenoid contour loss on radiograph (P = .07), participation sports, or ISIS (mean = 3.4 success vs 3.9 failure, P > .05).

CONCLUSIONS

At a mean follow-up of 42 months was an 11.5% failure rate after arthroscopic Bankart stabilization surgery. This study shows no correlation between treatment outcome and the ISIS measure, given a mean score of 3.4 for the overall cohort with little difference identified in those who failed. However, several important parameters previously unidentified were detected including, GBL greater than 14.5%, Hill-Sachs volume greater than 1.3 cm³, and duration of instability symptoms (>3 months). The ISIS may need to be redesigned to incorporate variables that more accurately portray the actual risk of failure after arthroscopic stabilization, including quantification of both glenoid and humeral head bone loss.

LEVEL OF EVIDENCE

III (Retrospective Case Series).

Editorial Commentary: Anterior Shoulder Instability in Adolescent Athletes: "Slaying the Hydra" Is a Subtle Art

Anterior shoulder instability in adolescent athletes can be cumbersome to identify and treat. An algorithm is to divide the patients into primary and revision cases then to further subdivide patients who have glenoid bone loss <20% and/or an engaging or off-track Hill-Sachs lesion. A bipolar lesion with either of these conditions is an indication for a bone block open Laterjet procedure. In the revision setting, the threshold for Laterjet is lower. Soft-tissue lesions are indications for a Bankart or labral repair. With the proper attention given to concomitant labral, biceps, and rotator cuff pathology, Hill-Sachs lesions less than 1 cm are left alone. However, in situations where lesions are deeper than 1 cm, an arthroscopic remplissage is indicated. An optimal repair aims to create a labral bumper and a bony bed for the soft tissue to heal, whereas inferior quality of soft tissue indicates a segmental labral reconstruction. Reconstructing large capsular rents with torn ligaments with allograft anterior capsular repair is also needed for proper biomechanical restoration.

Factors related to large bone defects of bipolar lesions and a high number of instability episodes with anterior glenohumeral instability

Background

Significant bone defects are associated with poor clinical results after surgical stabilization in cases of glenohumeral instability. Although multiple factors are thought to adversely affect enlargement of bipolar bone loss and increased shoulder instability, these factors have not been sufficiently evaluated. The purpose of this study was to identify the factors related to greater bone defects and a higher number of instability episodes in patients with glenohumeral instability.

Methods

A total of 120 consecutive patients with symptomatic unilateral instability of the glenohumeral joint were retrospectively reviewed. Three-dimensional surface-rendered/registered models of bilateral glenoids and proximal humeri from computed tomography data were matched by software, and the volumes of bone defects identified in the glenoid and humeral head were assessed. After relationships between objective variables and explanatory variables were evaluated using bivariate analyses, factors related to large bone defects in the glenoid and humeral head and a high number of total instability episodes and self-irreducible dislocations greater than the respective 75th percentiles were evaluated using logistic regression analyses with significant variables on bivariate analyses.

Results

Larger humeral head defects (P < .001) and a higher number of total instability episodes (P = .032) were found to be factors related to large glenoid defects. On the other hand, male sex (P = .014), larger glenoid defects (P = .015), and larger number of self-irreducible dislocations (P = .027) were related to large humeral head bone defects. An increased number of total instability episodes was related to longer symptom duration (P = .001) and larger glenoid defects (P = .002), and an increased number of self-irreducible dislocations was related to larger humeral head defects (P = .007).

Conclusions

Whereas this study showed that bipolar lesions affect the amount of bone defects reciprocally, factors related to greater bone defects differed between the glenoid and the humeral head. Glenoid defects were related to the number of total instability episodes, whereas humeral head defects were related to the number of self-irreducible dislocations.

In-Season Management of Anterior Shoulder Instability

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

Evaluating the effects of arthroscopic Bankart repair and open Latarjet shoulder stabilisation procedures on shoulder joint neuromechanics and function: a single-centre, parallel-arm trial protocol

Introduction

Shoulder instability injuries are common in sports involving collisions and overhead movements. Arthroscopic Bankart repair and the open Latarjet are two commonly used surgical stabilisation procedures. There is a lack of knowledge surrounding movement strategies, joint loading and muscle strength after each of these procedures. This study will compare: (1) shoulder joint neuromechanics during activities of daily living and an overhead sporting task; (2) shoulder range of motion; (3) shoulder strength; and (4) self-reported shoulder function and health status, between individuals who have undergone an arthroscopic Bankart repair versus open Latarjet.

Methods and analysis

This is a prospective cohort, single-centre, non-randomised parallel arm study of surgical interventions for athletic shoulder instability injuries. Thirty participants will be recruited. Of these, 20 will have experienced one or more traumatic shoulder instability injuries requiring surgical stabilisation—and will undergo an arthroscopic Bankart repair or open Latarjet procedure. The remaining 10 participants will have no history of shoulder instability injury and act as controls. Participants will undergo baseline testing and be followed up at 3, 6 and 12 months. A two-way (group×time) analysis of variance with repeated measures on one factor (ie, time) will compare each outcome measure between groups across time points.

Ethics and dissemination

This study was approved by the Barwon Health and Deakin University Human Research Ethics Committees. Outcomes will be disseminated through publications in peer-reviewed journals and presentations at relevant scientific conferences.

Trial registration number

Australian and New Zealand Clinical Trials Registry (ACTRN12620000016932).

Are there racial differences between patients undergoing surgery for shoulder instability? Data from the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Group

BACKGROUND

The purpose of this study was to identify differences related to race in preoperative and intraoperative findings of patients undergoing operative treatment for shoulder instability.

METHODS

Data from the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort were used. Of 1010 patients, 995 provided race and ethnicity information and were included in the analyses. Demographic characteristics, injury history, radiographic and intraoperative findings, and preoperative patient-reported instability, pain, and function were compared (1) between white and minority patients and (2) in a subgroup analysis between white patients and the 3 largest minority groups. The Distressed Communities Index (DCI) score was recorded for each patient's home ZIP code. Multiple logistic regressions were performed to determine whether models consisting of race/ethnicity, insurance carrier, and/or DCI score were predictive of bone and cartilage loss at the time of surgery.

RESULTS

Compared with white patients, a greater percentage of US minority patients had ≥2 dislocations (68.0% vs. 57.1%, P = .01), which corresponded with more frequent articular cartilage lesions (62.2% vs. 51.0%, P = .007) and increased frequencies of glenoid bone loss > 10% (16.2% vs. 8.7%, P = .03) and Hill-Sachs lesions (68.6% vs. 56.0%, P = .004). Specifically, when compared with white patients, African American and Asian patients showed significantly increased frequencies of glenoid bone loss > 10% (19.7% of African American patients, 18.4% of Asian patients, and 8.9% of white patients; P = .01) and Hill-Sachs lesions (65.6%, 71.7%, and 52.4%, respectively; P = .02). Race was an independent predictor of articular cartilage lesions (P = .04) and the presence of Hill-Sachs lesions (P = .01). A higher DCI score (P = .03) and race (P = .04) were both predictive of having glenoid bone loss > 10%.

CONCLUSION

We found that minority race was associated with increased number of preoperative dislocations and increased frequency of articular cartilage and Hill-Sachs lesions at the time of surgery, and both minority race and an increased DCI score were associated with glenoid bone loss > 10%. Further research is needed to understand the underlying reason for these differences and to optimize care for all patients with shoulder instability.

Postoperative Management Following Arthroscopic Bankart Repair in Adolescents and Young Adults: A Systematic Review

PURPOSE

The purpose of this study was to review systematically the literature concerning postoperative management following arthroscopic Bankart repair for traumatic anterior shoulder instability in adolescent and young adult (≤ 25 years) athletes.

METHODS

The Pubmed, Medline, EMBASE, EBSCO (CINAHL), and Google Scholar databases were systematically searched according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to identify all studies reporting postoperative rehabilitation guidelines following arthroscopic Bankart repair in the adolescent and young adult population. The Methodological Index for Nonrandomized Studies instrument and Modified Coleman Methodology Score were used for quality assessment of the included studies. All aspects of rehabilitation were extracted and analyzed, including type/duration of immobilization, range of motion, strength, and return to sport (RTS) criteria.

RESULTS

Screening yielded 17 eligible studies with a total of 675 patients and an average age of 18.3 years. There was considerable variation with regard to reported postoperative rehabilitation guidelines. Of the 17 studies, 15 reported the duration of immobilization; there was a mean of 4 weeks (range, 2-6 weeks). Range of motion and strength restrictions were reported in 15 (88.2%) and 13 (76.4%) studies, respectively. All of the 17 studies included an expected timeframe for RTS, but only 5 of the studies (29.4%) included either subjective or objective criteria to determine safe RTS. Differences in outcomes were unable to be assessed due to large study heterogeneity.

CONCLUSION

Considerable variation is reported in postoperative rehabilitation guidelines following arthroscopic Bankart repair for traumatic shoulder instability in the adolescent and young adult population. All studies used time-based criteria for determining RTS, but subjective and/or objective criteria were lacking in the majority of studies. The current literature lacks data to generate evidence-based rehabilitation protocols in this young athletic population.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II-IV studies.

Clinical and radiological examination of bony-mediated shoulder instability

The coexistence of glenoid and humeral head bone defects may increase the risk of recurrence of instability after soft tissue repair.

Revealed factors in medical history such as male gender, younger age of dislocation, an increasing number of dislocations, contact sports, and manual work or epilepsy may increase the recurrence rate of instability.

In physical examination, positive bony apprehension test, catching and crepitations in shoulder movement may suggest osseous deficiency.

Anteroposterior and axial views allow for the detection of particular bony lesions in patients with recurrent anterior shoulder instability.

Computed Tomography (CT) with multiplanar reconstruction (MPR) and various types of 3D rendering in 2D (quasi-3D-CT) and 3D (true-3D-CT) space allows not only detection of glenoid and humeral bone defects but most of all their quantification and relations (engaging/not-engaging and on-track/off-track) in the context of bipolar lesion.

Magnetic resonance imaging (MRI) is increasingly developing and can provide an equally accurate measurement tool for bone assessment, avoiding radiation exposure for the patient.

Cite this article: EFORT Open Rev 2020;5:815-827. DOI: 10.1302/2058-5241.5.200049

Does glenoid remodeling occur with an erosion-type bone loss after arthroscopic Bankart repair?

Introduction

Fragment-type glenoid bone loss is known to remodel after arthroscopic Bankart repair. To our knowledge, no studies have been reported about the morphologic changes of the erosion-type bone loss.

Aim

To determine the morphologic changes of erosion-type glenoid bone loss after arthroscopic Bankart repair.

Methods

Twenty-eight patients (mean age: 31 years) with traumatic anterior glenohumeral instability with an erosion-type glenoid bone loss <25% underwent arthroscopic Bankart repair. The minimum follow-up was 2 years. Pre- and postoperative bilateral computed tomography scans were performed in all patients. The width and surface area of the glenoid were measured by a software program and compared pre- and postoperatively.

Results

The recurrence rate was 7.1% (2 of 28 shoulders). The size of the bone loss was 7.2% ± 5.3% (mean ± standard deviation). The preoperative glenoid width and area were 24.9 ± 2.2 mm and 7.0 ± 0.8 cm², respectively, and the postoperative ones (2 years after surgery) were 24.7 ± 2.2 mm and 6.8 ± 0.8 cm², respectively. There were no significant differences between the pre- and postoperative glenoid width and area.

Discussion and conclusion

Unlike the fragment-type bone loss, the erosion-type bone loss <25% did not show any morphologic changes of the glenoid at least 2 years after arthroscopic Bankart repair.

Dynamic contact area ratio in shoulder instability: an innovative diagnostic technique measuring interplay of bony lesions

PURPOSE

The hypothesis of this study is that Dynamic Contact Area Ratio of the humerus and glenoid, measured with CT scans, is significantly reduced in patients with anterior shoulder instability compared to the Dynamic Contact Area Ratio in a control group of people without shoulder instability.

METHODS

Preoperative CT scans of patients who underwent surgery for anterior shoulder instability were collected. Additionally, the radiologic database was searched for control subjects. Using a validated software tool (Articulis) the CT scans were converted into 3-dimensional models and the amount the joint contact surface during simulated motion was calculated.

RESULTS

CT scans of 18 patients and 21 controls were available. The mean Dynamic Contact Area Ratio of patients was 25.2 ± 6.7 compared to 30.1 ± 5.1 in healthy subjects (p = 0.014).

CONCLUSION

Dynamic Contact Area Ratio was significantly lower in patients with anterior shoulder instability compared to controls, confirming the hypothesis of the study. The findings of this study indicate that calculating the Dynamic Contact Area Ratio based on CT scan images may help surgeons in diagnosing anterior shoulder instability.

LEVEL OF EVIDENCE

III.

Analysis of glenohumeral morphological factors for anterior shoulder instability and rotator cuff tear by magnetic resonance imaging

OBJECTIVE

The aim of this study was to investigate whether there are glenohumeral morphological differences between normal population, glenohumeral instability, and rotator cuff pathology.

METHOD

In this study, shoulder magnetic resonance (MR) images of 150 patients were evaluated. Patients included in the study were studied in three groups of 50 individuals: patients with anterior shoulder instability in group 1, patients with rotator cuff tear in group 2, and control subjects without shoulder pathology in group 3.

RESULTS

There were statistically significant differences between groups in evaluations for glenoid version, glenoid coronal height, glenoid coronal diameter, humeral axial and coronal diameters, and coracohumeral interval distances. Significant differences were observed between groups 2 and 3 in glenoid axial diameter, glenoid coronal height, glenoid depth, humeral coronal diameter, and coracohumeral distances.

CONCLUSION

The results obtained in this study suggest that glenoid version, glenoid coronal height and diameter, humeral diameter, and coracohumeral interval parameters in glenohumeral morphology-related parameters in patients with anterior instability are different from those of normal population and patients with rotator cuff pathology. In cases where there is a clinically difficult diagnosis, these radiological measurements will be helpful to clinicians in diagnosis and treatment planning, especially in cases of treatment-resistant cases.

The Number of Injury Events Associated With the Critical Size of Bipolar Bone Defects in Rugby Players With Traumatic Anterior Shoulder Instability

BACKGROUND

The size of a glenoid bone defect is responsible for reduction in shoulder stability and is correlated with the number of instability events. Biomechanical studies have suggested that it should be considered concomitantly with the Hill-Sachs lesion as "bipolar" bone defects for assessing structural degradation, but the definitive number of instability events associated with the critical size has not been investigated.

PURPOSE

To (1) confirm that the number of instability events is the predictor of a critical size of bipolar bone defects and (2) demonstrate the cutoff value of the number of instability events for these defects in rugby players with traumatic anterior shoulder instability.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

One-hundred forty-four rugby players with anterior shoulder instability underwent morphologic evaluation for glenoid and Hill-Sachs lesions by computed tomography and determination of the critical (a glenoid bone defect of ≥25% or an off-track Hill-Sachs lesion) and subcritical (a glenoid bone defect of ≥13.5%) size of bipolar bone defects. In the primary analysis, the prevalence of the critical and subcritical size of bipolar bone defects was investigated. In the secondary analysis, the authors explored the predictors for these bone defects and determined the cutoff value correlating with the critical and subcritical size of bipolar bone defects by applying receiver operating characteristic curves.

RESULTS

The primary analysis revealed that the prevalence of critical and subcritical size of bipolar bone defects was 20.8% and 61.8% of 144 shoulders, respectively. In the secondary analysis, multiple logistic regression analysis demonstrated that the total number of shoulder instability events and dominant shoulder were the significant factors associated with the critical and subcritical size of bipolar bone defects. The cutoff value for the number of instability events that correlated with critical bipolar bone defects was 6 for the dominant and 9 for the nondominant shoulder, whereas it was 4 for the dominant and 5 for the nondominant shoulder for subcritical bipolar bone defects.

CONCLUSION

The number of shoulder instability events and the dominant shoulder were the predictors for the critical and subcritical size of bipolar bone defects for a shoulder with traumatic instability. Four injury events should herald caution when treating rugby players with shoulder instability.

Management of primary anterior shoulder dislocations: a narrative review

Abstract

The recurrence rate following acute anterior shoulder dislocations is high, particularly in young, active individuals. The purpose of this paper is to provide a narrative overview of the best available evidence and results with regards to diagnostic considerations, comorbidities, position of immobilization, surgical versus conservative management, and time to return to play for the management of primary anterior shoulder dislocations. Three independent reviewers performed literature searches using PubMed, MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials. Randomized controlled trials and systematic reviews meeting inclusion criteria from 1930 to April 2019 were appraised and discussed with the intent to consolidate the best available evidence with regards to lowering recurrence rates. A majority of studies support early surgical intervention for individuals between 21 and 30 years of age following primary shoulder dislocations, as this group is particularly susceptible to recurrence. Conservative treatment plans favor 1–3 weeks of immobilization in internal rotation, followed by rehabilitation. Surgical methods are associated with longer time to return to play, but lower recurrence rates. Return to play time is best determined on an individualized basis, when subjective and objective function of both shoulders is determined to be symmetric. This paper broadly summarizes the best available evidence for the management of primary anterior shoulder dislocations. There remains a need for randomized studies to determine ideal long-term treatment following conservative or surgical management, as general timelines for returning to play following injury remain vague.

Level of evidence

IV, Narrative Review

Coracoacromial morphology: a contributor to recurrent traumatic anterior glenohumeral instability?

BACKGROUND

Although scapular morphology contributes to glenohumeral osteoarthritis and rotator cuff disease, its role in traumatic glenohumeral instability remains unknown. We hypothesized that coracoacromial and glenoid morphology would differ between healthy subjects and patients with recurrent traumatic anterior shoulder instability.

METHODS

Computed tomography scans of 31 cadaveric control scapulae and 54 scapulae of patients with recurrent traumatic anterior shoulder instability and Hill-Sachs lesions were 3-dimensionally reconstructed. Statistical shape modeling identified the modes of variation between the scapulae of both groups. Corresponding measurements quantified these modes in relation to the glenoid center (linear offset measures), defined by the best-fit circle of the inferior glenoid, or the glenoid center plane (angles), which bisects the glenoid longitudinally. Distances were normalized for glenoid size.

RESULTS

Compared with controls, the unstable coracoids were shorter (P = .004), with a more superior and medial offset of the tip (mean difference [MD], 7 and 3 mm, respectively; P < .001) and an origin closer to the 12-o'clock position (MD, 6°; P < .001). The unstable scapular spines originated closer to the 9-o'clock position (MD, 4°; P = .012), and the unstable acromions were more vertically oriented (MD, 6°; P < .001). The unstable glenoids had an increased height-width index (MD, 0.04; P = .021), had a flatter anterior-posterior radius of curvature (MD, 77 mm; P < .001), and were more anteriorly tilted (MD, 5°; P = .005).

CONCLUSIONS

Coracoacromial and glenoid anatomy differs between individuals with and without recurrent traumatic anterior shoulder instability. This pathologic anatomy is not addressed by current soft-tissue stabilization procedures and may contribute to instability recurrence.

Factors Influencing Surgeon's Choice of Procedure for Anterior Shoulder Instability: A Multicenter Prospective Cohort Study

PURPOSE

To investigate preoperative factors associated with selection of surgical treatment for anterior shoulder instability.

METHODS

Patient demographics, initial physical examinations, and patient-oriented outcome questionnaires were collected prospectively from 26 shoulder surgeons at 10 sites. Symptom duration, number of dislocations, sport, history of prior stabilization procedure, Hill-Sachs/glenoid bone loss, pain level, and failure of conservative treatment were recorded. Statistical analysis was performed with Fisher's exact test and logistic regression analysis.

RESULTS

A total of 564 patients who underwent surgical treatment for anterior shoulder instability from November 2012 to June 2017 were enrolled. Of these, 426 shoulders underwent arthroscopic stabilization alone, 38 underwent arthroscopic stabilization with remplissage, 28 underwent open Bankart repair, and 72 underwent a Latarjet procedure. Predictors for undergoing Latarjet (P < .003) were symptom duration (75% had symptoms for >1 year), number of dislocations (47% had >5 dislocations), revision surgery (69%), Hill-Sachs lesion size (45% had a lesion between 11% and 20% of the humeral head), and glenoid bone loss (75% of Latarjet patients had 11% to 30% loss). Predictors for undergoing open Bankart repair (P < .001) were number of dislocations (32% had >5 dislocations), revision surgeries (54%), and glenoid bone loss (11% of open Bankart patients had 11% to 20% loss). History of prior shoulder surgery was the only significant predictor of open versus arthroscopic Bankart procedure. Prediction models showed athletes involved in high-risk sports were 2.61 times more likely to have a Latarjet (P < .01).

CONCLUSIONS

Indications for the Latarjet were: humeral and glenoid bone loss, duration of symptoms, number of dislocations, and revision stabilizations. Athletes involved in high-risk sports were more likely to undergo the Latarjet procedure, even if other predictive factors were not present. The open Bankart procedure was the least common procedure performed, with a history of prior shoulder surgery being the only predictor for use when treating recurrent instability.

LEVEL OF EVIDENCE

Level II, prospective prognostic cohort investigation.

Is CT scan a predictor of instability in recurrent dislocation shoulder?

PURPOSE

Glenoid bone defect and the defect on the posterior-superior surface of the humerus "Hill-Sachs lesion" are the commonly seen bony lesions in patients with recurrent dislocation shoulder. Computed tomography (CT) scan is considered as the best option in assessing the bony defects in the recurrent dislocation shoulder. The aim of this study was to assess the clinical and radiological co-relation in the patients with recurrent dislocation shoulder.

METHODS

Forty-four patients of recurrent dislocation shoulder who were evaluated between January 2015 and December 2017 at a tertiary care center, clinically and radiologically using CT scan and meeting the inclusion criteria, were included. The correlation between the clinical history of the number of dislocations and the bone loss using CT scan was evaluated. Two sided statistical tests were performed at a significance level of α = 0.05. The analysis was conducted using IBM SPSS STATISTICS (version 22.0).

RESULTS

All the patients were male with mean age of 25.95 (SD ± 4.2) years were evaluated. Twenty-four patients sustained injury in sporting activities while 20 patients sustained injury in training. There were an average of 4.68 (SD ± 3.1, range 2-15, median 3) episodes of dislocation. Forty-one patients had the glenoid bone loss while 40 had the Hill-Sachs lesions. The mean glenoid width defect was 10.80% (range 0-27%) while the mean Hill-Sachs defect was 14.27 mm (range 0-26.6 mm). The mean area of bone loss of the glenoid surface was 10.81% (range 0-22.4%). The lesions were on track in 34 patients and off track in 10 patients.

CONCLUSIONS

CT scan of the shoulder joint is an effective method for assessing the amount of bone loss. The number of dislocations are correlated significantly with off-track lesions and the amount of bone loss on the glenoid and Hill-Sachs lesion. The glenoid width bone loss of more than 9.80% or Hill-Sachs defect of more than 14.80 mm are the critical defects after which the frequency of dislocations increases.

Recurrent Shoulder Instability: Do Morbidity and Treatment Differ Based on Insurance?

Background:

Patients with public insurance often face barriers to obtaining prompt orthopaedic care. For patients with recurrent traumatic anterior shoulder instability, delayed care may be associated with increasing bone loss and subsequently more extensive surgical procedures.

Purpose/Hypothesis:

The purpose of this study was to evaluate whether differences exist in patients undergoing treatment for shoulder instability between those with Medicaid versus non-Medicaid insurance. We hypothesized that at the time of surgery, Medicaid patients would have experienced greater delays in care, would have a more extensive history of instability, would have more bone loss, and would require more extensive surgical procedures than other patients.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients were identified who underwent surgical stabilization for traumatic anterior shoulder instability between January 1, 2011, and December 1, 2015, at a single sports medicine practice. Clinic, billing, and operative records were reviewed for each patient to determine age, sex, insurance type, total number of instability episodes, time from first instability episode to surgery, intraoperative findings, and procedure performed. Glenoid bone loss was quantified by use of preoperative imaging studies.

Results:

During this time period, 206 patients (55 Medicaid, 131 private insurance, 11 Tricare, 9 workers’ compensation) underwent surgical stabilization for traumatic anterior shoulder instability. Average wait time from initial injury to surgery was 1640 days (95% CI, 1155-2125 days) for Medicaid patients compared with 1237 days (95% CI, 834-1639 days) for others (P = .005). Medicaid patients were more likely to have sustained 5 or more instability events at the time of surgery (OR, 3.3; 95% CI, 1.64-6.69; P = .001), had a higher risk of having 15% or more glenoid bone loss on preoperative imaging (OR, 3.5; 95% CI, 1.3-10.0; P = .01), and had a higher risk of requiring Latarjet or other open stabilization procedures as opposed to an arthroscopic repair (OR, 3.0; 95% CI, 1.5-6.2; P = .002) when compared with other patients.

Conclusion:

Among patients undergoing surgery for traumatic anterior shoulder instability, patients with Medicaid had significantly more delayed care. Correspondingly, they reported a more extensive history of instability, were more likely to have severe bone loss, and required more invasive stabilization procedures.

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

BACKGROUND

Determining the amount of glenoid bone loss in patients after anterior glenohumeral instability events is critical to guiding appropriate treatment. One of the challenges in treating the shoulder instability of young athletes is the absence of clear data showing the effect of each event.

PURPOSE

To prospectively determine the amount of bone loss associated with a single instability event in the setting of first-time and recurrent instability.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The authors conducted a prospective cohort study of 714 athletes surveilled for 4 years. Baseline assessment included a subjective history of shoulder instability. Bilateral noncontrast shoulder magnetic resonance imaging (MRI) was obtained for all participants with and without a history of previous shoulder instability. The cohort was prospectively followed during the study period, and those who sustained an anterior glenohumeral instability event were identified. Postinjury MRI with contrast was obtained and compared with the screening MRI. Glenoid width was measured for each patient's pre- and postinjury MRI. The projected total glenoid bone loss was calculated and compared for patients with a history of shoulder instability.

RESULTS

Of the 714 athletes (1428 shoulders) who were prospectively followed during the 4-year period, 22 athletes (23 shoulders) sustained a first-time anterior instability event (5 dislocations, 18 subluxations), and 6 athletes (6 shoulders) with a history of instability sustained a recurrent anterior instability event (1 dislocation, 5 subluxations). On average, there was statistically significant glenoid bone loss (1.84 ± 1.47 mm) after a single instability event ( P < .001), equivalent to 6.8% (95% CI, 4.46%-9.04%; range, 0.71%-17.6%) of the glenoid width. After a first-time instability event, 12 shoulders (52%) demonstrated glenoid bone loss ≥5% and 4 shoulders, ≥13.5%; no shoulders had ≥20% glenoid bone loss. Preexisting glenoid bone loss among patients with a history of instability was 10.2% (95% CI, 1.96%-18.35%; range, 0.6%-21.0%). This bone loss increased to 22.8% (95% CI, 20.53%-25.15%; range, 21.2%-26.0%) after additional instability ( P = .0117). All 6 shoulders with recurrent instability had ≥20% glenoid bone loss.

CONCLUSION

Glenoid bone loss of 6.8% was observed after a first-time anterior instability event. In the setting of recurrent instability, the total calculated glenoid bone loss was 22.8%, with a high prevalence of bony Bankart lesions (5 of 6). The findings of this study support early stabilization of young active patients after a first-time anterior glenohumeral instability event.

Editorial Commentary: Middle-Age Does Not Confer Immunity From Recurrent Instability After Arthroscopic Bankart Repair

Recurrent anterior shoulder instability remains a challenge to treat with arthroscopy, as the rate of postoperative instability remains high in certain patient populations. Indications for performing an "anatomic" arthroscopic reconstruction (isolated Bankart repair) are narrowing as surgeons identify risk factors for failure with this approach. In particular, the presence of certain bone loss patterns that occur with high numbers of instability events should prompt consideration for nonanatomic reconstruction, such as Latarjet or Hill-Sachs remplissage, to reduce the rate of postoperative recurrent instability.

Our First experience of Using Biodegradable Implants in Latarjet – Bristow Surgical Procedure at Chronic Posttraumatic Anterior Shoulder Insta

Background. Multi-layer spiral computed tomography shows that the main cause of shoulder instability is glenoid cavity bone defect. The aim of our research was to assess the effectiveness and safety of biodegradable implants in the treatment of patients with chronic posttraumatic anterior shoulder instability under conditions of bone defect of glenoid cavity margin by the restoration of anatomic shape and structure of scapula articular surface.

Materials and methods. We performed a pilot study based on the results of surgical treatment of 7 patients using 4.5 mm biodegradable compressing screws. In preoperative period, all patients had standard two-dimensional X-rays and MSCT with 3D-reconstruction. In postoperative period, all patients had check-up X-ray right after the surgery and MRI in 3 months after the surgery.

Results. The results of the treatment were assessed by common clinical criteria, functional criteria, X-ray evidence and intraand postoperative complications. We registered strong functioning of an arm and an increase in the range of motions. Data from Rowe/Zarins and DASH questionnaires showed that the patients totally recovered. X-ray evidence showed consolidation of non-free autograft to the zone of scapula bone defect without osteolysis or widening of a drilled hole. We did not observe either a failure of union, or any formation of false joint, or any screw fractures in bone tissue. Beyond that, we did not observe any complication in postoperative period and early postoperative complications in particular.

Conclusion. Pilot study with use of modern biodegradable implants in osteoplastic stabilization of shoulder joint at recurring instability showed their effectiveness and safety in patients of young and active working age. However, considering small number of patients in pilot study we cannot extrapolate our results to all similar and analogue cases of using biodegradable implants. In this regard, it is necessary to perform major multicenter clinical randomized study for further long-term observation and detection of possible unwanted side effects.

Surgical treatment outcomes after primary vs recurrent anterior shoulder instability

INTRODUCTION

The aim of this study is to compare the outcomes of surgical management after primary anterior shoulder dislocation to the outcomes of patients who have surgical stabilization after recurrent anterior shoulder instability.

METHODS

A Medline (PubMed) search was performed in November of 2016 using the following key terms: shoulder, labrum, Bankart, instability, repair, outcome, recurrent. In May 2017 a Cochrane search was performed using similar key terms to ensure we included all studies. Only level I and II studies were included.

RESULTS

There were three studies that compared primary repair to delayed repair. In all three studies, the rate of recurrence was higher in group R than group S. When pooled, there was not a statistically significant difference between these groups, but there was a slightly higher odds of recurrence in group R (pooled OR 2.08, CI 0.69-6.26, p = 0.19). No significant differences were appreciated in functional outcomes or complications in these two groups.

CONCLUSION

Further level I and level II studies to compare surgical treatment after first time and recurrent instability are needed. This study failed to find a statistically significant difference in recurrence rates in patients who had stabilization acutely after a single episode compared to patients with recurrent instability events, although results suggest there may be a small benefit in primary stabilization.

Editorial Commentary: Is It Time to Take a Stand? When Arthroscopic Bankart Repair Is No Longer a Viable Option for Anterior Shoulder Instability

Recurrent anterior instability remains a challenging pathology to treat effectively. Arthroscopic Bankart repair, with its low invasiveness and complication rates, is readily the first, as well as most commonly, used procedure. However, some outcomes studies have reported an unacceptably high failure rate. As such, the ideal candidate for an arthroscopic repair has yet to be fully defined, mainly because of the multiple risk factors for failure after arthroscopic instability repair. Among those factors, recurrence of an instability event is clearly a risk factor for worse outcomes after arthroscopic instability repair. This may be due to an association between recurrent instability and an increase in glenoid bone loss, humeral bone loss, and more extensive labral tears, as well as more capsular, ligamentous, and rotator cuff injuries. Patients who present with 2 preoperative dislocations and a duration of instability symptoms of more than 6 months, as well as off-track Hill-Sachs lesions, may not be ideal candidates for arthroscopic instability repair. There is a "cost" to waiting on surgery after a first dislocation.

The Incidence of Glenohumeral Bone and Cartilage Lesions at the Time of Anterior Shoulder Stabilization Surgery: A Comparison of Patients Undergoing Primary and Revision Surgery

BACKGROUND

Intra-articular glenohumeral joint changes frequently occur after shoulder instability events.

PURPOSE

(1) To compare demographic characteristics, baseline patient-reported outcomes, and intraoperative findings for patients undergoing primary or revision shoulder stabilization surgery and (2) to determine the incidence of glenohumeral bone and cartilage lesions in this population while identifying factors independently associated with these lesions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group shoulder instability database was used to identify all prospectively enrolled patients undergoing shoulder stabilization surgery for anterior instability between October 2012 and September 2016. Any patient who underwent surgery for posterior or multidirectional shoulder instability or concomitant rotator cuff repair surgery was excluded. Patient demographic characteristics, preoperative patient-reported outcomes, and intraoperative findings, including glenohumeral bone and cartilage lesions, were compared for patients undergoing primary and revision shoulder stabilization surgery. Additionally, patients with and without glenohumeral bone and cartilage lesions were compared and independent associations determined using multivariate analysis.

RESULTS

There were 545 patients available for analysis (461/545 [84.6%] primary; 84/545 [15.4%] revision). Patients undergoing revision surgery were older ( P = .001), were more frequently smokers ( P = .022), had a greater number of instability events before surgery ( P = .047), more frequently required reduction assistance ( P < .001), and had lower Short Form-36 (SF-36) Mental Component Summary ( P = .020) and Western Ontario Shoulder Instability Index (WOSI) ( P = .026) scores preoperatively. Additionally, patients undergoing revision surgery had a higher frequency of bone and cartilage lesions than those undergoing primary surgery (47.6% vs 18.4%, respectively; P < .001). Male sex, revision surgery, black race, increasing body mass index, increasing patient age, and lower preoperative SF-36 Physical Component Summary score were independently associated with the presence of glenohumeral bone and cartilage lesions at the time of shoulder stabilization surgery. Revision surgery was strongly associated with the presence of glenohumeral bone and cartilage lesions (odds ratio [OR], 4.381 [95% CI, 2.591-7.406]) and glenoid bone loss greater than 10% (OR, 9.643 [95% CI, 5.128-18.134]) or 20% (OR, 13.076 [95% CI, 5.113-33.438]) of the glenoid width.

CONCLUSION

Glenohumeral bone and cartilage lesions are common at the time of shoulder stabilization surgery, occurring more frequently in patients undergoing revision surgery as compared with primary surgery. On the basis of these findings, future prospective studies should aim to compare the clinical outcomes in these 2 groups.

Modified Bristow-Latarjet procedure for treatment of recurrent traumatic anterior glenohumeral dislocation

Objective

Retrospective case–control study of authors experience in the modified Bristow-Latarjet procedure for treatment of recurrent traumatic anterior glenohumeral dislocation with glenoid bone injury.

Methods

Sample with 102 recurrent glenohumeral dislocation cases submitted to modified Bristow-Latarjet procedure. Indications included situations of recurrent traumatic anterior glenohumeral instability with more than two dislocation episodes and with glenoid bone attritional or fragmentary injuries, without possibility of reconstruction. Mean follow-up time was 5.33 ± 2.74 years (minimum 1; range 1–13).

Results

The mean Walch-Duplay Score at the last evaluation was 91.23 ± 11.46 (range 15–100). The functional score of patients with glenoid bone loss greater than 20% did not show a significant difference in comparison with patients with glenoid bone loss lower than 20% (90 vs. 92, respectively). The functional score also did not show a significant difference between sports practice categories and between recreational and competitive practice, being excellent (greater than 90) in every category. There were no dislocation recurrences and the only complications were a case of persistent instability and a screw revision. Mild glenohumeral osteoarthrosis imaging signs were identified in 7.84% of the patients; however, their functional scores were not significantly different in comparison to other patients.

Conclusion

The modified Bristow-Latarjet procedure is a very effective procedure with few complications in the medium-term, showing very satisfactory functional outcomes in the treatment of recurrent traumatic anterior glenohumeral dislocation associated with glenoid bone injury.

The Open Bankart Repair for Traumatic Anterior Shoulder Instability in Teenage Athletes

BACKGROUND

Traumatic anterior shoulder instability from recurrent dislocations or subluxations is a debilitating problem for the teenage athlete. The risk of recurrent instability is high in this adolescent population. We performed a retrospective case series analysis of adolescent athletes with recurrent instability treated with open Bankart repair and evaluated functional outcomes as well as redislocation rates.

METHODS

The retrospective study included 21 teenage patients with Bankart lesions and recurrent anterior shoulder instability. There were 19 males (90%) and 2 females (10%) with an average age of 16 years (range, 14 to 18 y). Patients were evaluated based on Rowe and UCLA shoulder scores, return to previous level of sport, external rotation, and recurrence.

RESULTS

The average number of anchors used to repair the Bankart lesion was 3 (range, 2 to 5). One patient was lost to follow-up at 6 months after surgery. The remaining 20 patients all had at least 2-year follow-up. The recurrent instability rate was zero. In total, 100% of patients had an excellent result based on an average Rowe score of 96.5 points of 100 points (a score of 90 to 100 is an excellent result). In total, 100% of patients had good/excellent result based on an average UCLA shoulder score of 34 of 35 (a score >27 is a good/excellent result). At final follow-up, 7 patients (34%) had lost an average of 11 degrees of external rotation (range, 5 to 20 degrees) on the injured shoulder with the arm at the side compared with the noninjured shoulder.

CONCLUSIONS

Contact teenage athletes with recurrent anterior shoulder instability can be treated with open Bankart repair with a low recurrence, excellent functional shoulder outcomes, and return to sport. A small amount of external rotation may be lost with this technique. Care must be taken when considering this method with throwing athletes (ie, quarterback or pitcher). The open Bankart should remain a viable alternative for the adolescent population with recurrent anterior instability.

LEVEL OF EVIDENCE

Level IV.

Natural History of Anterior Shoulder Instability

BACKGROUND

The shoulder is the most complex joint in the body. The large freedom of motion in this joint is the main cause of instability. Instability varies in its degree, direction, etiology and volition and there is a large spectrum of conditions.

METHODS

Based on literature research and also in our own experience, we propose to elucidate the reader about the natural history of instability and its importance for the appropriate management of this pathology, by answering the following questions: What happens in the shoulder after the first dislocation? Which structures suffer damage? Who are the patients at higher risk of recurrence? How does the disease evolve without treatment? Will surgical treatment avoid future negative outcomes and prevent degenerative joint disease? Who should we treat and when?

RESULTS

80% of anterior-inferior dislocations occur in young patients. Recurrent instability is common and multiple dislocations are the rule. Instability is influenced by a large number of variables, including age of onset, activity profile, number of episodes,delay between first episode and surgical treatment.

CONCLUSION

Understanding the disease and its natural evolution is determinant to decide the treatment in order to obtain the best outcome. It is crucial to identify the risk factors for recurrence. Delay in surgical treatment, when indicated, leads to worse results. Surgical technique should address the type and severity of both soft tissue and bone lesions, when present.

Three-dimensional quantitative analysis of humeral head and glenoid bone defects with recurrent glenohumeral instability

BACKGROUND

Although bone defects of the humeral head and glenoid could affect glenohumeral instability, bone loss has not been sufficiently evaluated. The purpose of this study was to quantify bone defects 3-dimensionally in cases with glenohumeral instability.

METHODS

Three-dimensional surface models of bilateral proximal humeri and glenoids were reconstructed from computed tomography scans of 90 patients with symptomatic, unilateral, recurrent glenohumeral instability. The left-side models were mirrored, and intact bone areas were matched to those of the right-side models. The volume, length, width, and depth of identified bone defects were assessed. After the values were corrected by patient height, the characteristics of the bone defects were evaluated.

RESULTS

Bone defects were present in 97.8% of the humeral heads and 96.7% of the glenoids, and women had significantly smaller bone defects than men did. The volume of humeral head defects had a mild correlation with that of glenoid defects. The number of traumatic episodes was not correlated with humeral head bone defects, but it was positively correlated with glenoid bone defects. Patients with recurrent dislocations had significantly deeper and larger Hill-Sachs lesions than the other cases.

CONCLUSION

Bone defects of the humeral head and the glenoid in cases with symptomatic traumatic glenohumeral instability were quantified 3-dimensionally using a computed tomography surface-matching technique. Almost all cases showed bone defects in the humeral head and glenoid compared with the intact shoulder, and such bone defects may be more common than previously reported. This study suggested that bipolar bone lesions are not always created by the same mechanism.

Glenohumeral and scapulohumeral kinematic analysis of patients with traumatic anterior instability wearing a shoulder brace: a prospective laboratory study

PURPOSE

To assess the effectiveness of a novel glenohumeral joint immobilizer, the S2 Shoulder Stabilizer^®, by evaluating shoulder kinematics with a stereophotogrammetry system.

METHODS

Participants in this prospective laboratory study were recruited from patients with anterior traumatic instability awaiting arthroscopic glenohumeral stabilization. Glenohumeral and scapulohumeral kinematic data (arm abduction-adduction and internal-external rotation, and scapular pronation-retraction and mediolateral rotation) were collected twice, without and with the brace, using a VICON™ motion capture system, and processed with MATLAB^® software.

RESULTS

The tests showed a significantly lower joint angle during abduction-adduction (p = 0.0022) and external rotation (p = 0.0076) and a significantly lower (p = 0.0022) mediolateral scapular rotation angle in the limbs wearing the immobilizer. Humeral head translation during abduction-adduction and internal-external rotation was also lower in the patients wearing the brace.

CONCLUSIONS

The immobilizer significantly limited joint excursion in all planes of movement except internal rotation. The narrower humeral head translation with respect to the trunk, measured in the tests with the brace, demonstrates that the immobilizer achieves the goal of preserving joint stability in the movements that are at risk of dislocation.

Imaging of shoulder instability

This extended review tries to cover the imaging findings of the wide range of shoulder injuries secondary to shoulder joint instability. Usefulness of the different imaging methods is stressed, including radiography, computed tomography (CT) and magnetic resonance. The main topics to be covered include traumatic, atraumatic and minor instability syndromes. Radiography may show bone abnormalities associated to instability, including developmental and post-traumatic changes. CT is the best technique depicting and quantifying skeletal changes. MR-arthrography is the main tool in diagnosing the shoulder instability injuries.

Trends in Surgical Management of Shoulder Instability

Background:

Optimal surgical management of anterior shoulder instability remains controversial. There is a need to assess the most recent trends for primary and revision shoulder stabilization surgery using a national database significantly larger than those previously utilized.

Hypothesis:

Most shoulder stabilization procedures are performed arthroscopically. Examining revision procedures, we hypothesized that open procedures would result in decreased revision stabilizations compared with arthroscopic procedures and that most revision procedures would be open Bankart or bone transfer procedures regardless of the index procedure technique.

Study Design:

Descriptive epidemiology study.

Methods:

The MarketScan Database was searched using International Classification of Diseases–Ninth Revision (ICD-9) and Current Procedural Terminology (CPT) codes to identify patients who underwent any shoulder stabilization procedure between 2008 and 2012. Regression analysis was used to evaluate trends between patient groups. The Cochran-Armitage trend test was used to identify differences in trends seen yearly. Odds ratios (ORs) were calculated to compare the likelihood of undergoing a revision stabilization procedure.

Results:

A total of 66,564 shoulder stabilization procedures were identified from 2008 through 2012: 60,248 arthroscopic stabilization procedures (90.5%) and 6316 open stabilization procedures (9.5%), including 1623 bone block procedures. Arthroscopic stabilization procedures increased in total number and percentage of all procedures in each year of the study. Bone block procedures increased in number each year, although other open procedures decreased during the study period. Males underwent more stabilization procedures, while patients between the ages of 10 and 19 years were most likely to undergo any procedure. Patients who underwent bone block stabilization were significantly less likely to undergo a second stabilization procedure during the study period when compared with open Bankart repair (OR, 0.582; 95% CI, 0.405-0.836; P < .05) and arthroscopic Bankart repair (OR, 0.587; 95% CI, 0.418-0.824; P < .05). No statistically significant difference in revision stabilization was seen when comparing arthroscopic versus open Bankart repair (OR, 0.934; 95% CI, 0.863-1.139).

Conclusion:

Although the number of arthroscopic shoulder stabilization surgeries continues to increase, our data show a consistent increase, not seen in prior studies, in the number of bone block procedures. Contrary to some studies, there was no significant difference in the likelihood of a second procedure between patients initially undergoing arthroscopic compared with open Bankart repair.

Classification and Analysis of Attritional Glenoid Bone Loss in Recurrent Anterior Shoulder Instability

BACKGROUND

Recognition and proper treatment of glenoid bone loss (GBL) are important for successful management of anterior shoulder instability. Although GBL has been described as the amount of bony loss from the front of the glenoid, there is also a fragment of bone that is usually displaced and often undergoes attrition. Thus, due to attritional bone loss (ABL) of the fragment, insufficient bone is left to fully reconstruct the glenoid.

PURPOSE

To (1) evaluate ABL of the glenoid fragment in recurrent anterior shoulder instability and (2) correlate ABL with clinical history, fragment size, and radiographic findings.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

GBL was evaluated on 3-dimensional computed tomography (3D CT) en-face view and was measured as percentage loss. The bone fragment size was measured, and attrition of the fragment was determined by evaluation of the amount remaining relative to the initial defect; patients were stratified into minimal (<34%), moderate (34% to <67%), and severe (≥67%) attritional loss groups. Clinical history and demographics were correlated to ABL, and GBL and ABL were compared.

RESULTS

The overall median percentage GBL was 15.3% (interquartile range [IQR], 9.9%-20.0%), with a mean (±SD) percentage GBL of 16.5% ± 9.0%. Study participants had a corresponding median percentage ABL of 75.8% (IQR, 53.8%-95.7%) and a mean percentage ABL of 72.0% ± 24.4%. A total of 61.2% of patients (n = 85) exhibited severe ABL, while 30.2% had moderate ABL and 8.6% had minimal ABL. The total time of instability was significantly associated with percentage of attritional bone loss ( P < .05). In addition, the time of instability was greatest in patients in the third tertile of ABL (≥87.5%; P = .08). A significant difference was found in total time of instability among patients in the highest tertile of ABL (38.6 months) versus both the middle (26.7 months) and lowest (32.8 months) tertiles ( P < .05).

CONCLUSION

The study results indicate that in the majority of patients with recurrent anterior instability, GBL presents with extensive attrition of the bone fragment independent of initial glenoid bone loss; therefore, surgeons should be cognizant that the remaining bone fragment is unable to reconstitute glenoid bone stock. In addition, the results showed more attritional bone loss in patients with a longer duration of instability symptoms, indicating a role for incorporating symptom duration in determining proper management.

Mean Glenoid Defect Size and Location Associated With Anterior Shoulder Instability: A Systematic Review

BACKGROUND

There is a strong correlation between glenoid defect size and recurrent anterior shoulder instability. A better understanding of glenoid defects could lead to improved treatments and outcomes.

PURPOSE

To (1) determine the rate of reporting numeric measurements for glenoid defect size, (2) determine the consistency of glenoid defect size and location reported within the literature, (3) define the typical size and location of glenoid defects, and (4) determine whether a correlation exists between defect size and treatment outcome.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

PubMed, Ovid, and Cochrane databases were searched for clinical studies measuring glenoid defect size or location. We excluded studies with defect size requirements or pathology other than anterior instability and studies that included patients with known prior surgery. Our search produced 83 studies; 38 studies provided numeric measurements for glenoid defect size and 2 for defect location.

RESULTS

From 1981 to 2000, a total of 5.6% (1 of 18) of the studies reported numeric measurements for glenoid defect size; from 2001 to 2014, the rate of reporting glenoid defects increased to 58.7% (37 of 63). Fourteen studies (n = 1363 shoulders) reported defect size ranges for percentage loss of glenoid width, and 9 studies (n = 570 shoulders) reported defect size ranges for percentage loss of glenoid surface area. According to 2 studies, the mean glenoid defect orientation was pointing toward the 3:01 and 3:20 positions on the glenoid clock face.

CONCLUSION

Since 2001, the rate of reporting numeric measurements for glenoid defect size was only 58.7%. Among studies reporting the percentage loss of glenoid width, 23.6% of shoulders had a defect between 10% and 25%, and among studies reporting the percentage loss of glenoid surface area, 44.7% of shoulders had a defect between 5% and 20%. There is significant variability in the way glenoid bone loss is measured, calculated, and reported.