Clinical outcomes of open Latarjet-Patte procedures performed for recurrent anterior shoulder instability with primary bone loss versus failed arthroscopic Bankart repair

Background

The purpose of this study is to compare the outcomes of Latarjet-Patte procedures (LPs) performed for primary glenohumeral instability surgery in the setting of critical bone loss (LP-BL) versus salvage surgery performed after a failed primary arthroscopic Bankart repair (LP-FB).

Methods

Patients who underwent an LP from 2017 to 2021 were identified from the senior author's database and separated into cohorts by LP indication. Data abstracted from electronic medical records included demographic information, preoperative clinical scores, radiological imaging, and complications. Postoperative clinical outcome scores collected after a 2-year minimum follow-up included: patient-reported outcomes measurement information system (PROMIS) upper extremity (UE), PROMIS Pain interference, PROMIS pain intensity, American Shoulder and Elbow Surgeons (ASES), and Visual Analog Scale pain scores.

Results

A total of 47 patients (LP-BL: n=29, LP-FB: n=18) with a mean age of 29 years (range, 15-58 years) were included in this study. Both cohorts achieved good upper extremity functionality without significant differences as indicated by mean PROMIS UE (LP-BL: 52.6±10.0 vs. LP-FB: 54.6±7.6, P=0.442) and ASES scores (LP-BL: 89.9±15.7 vs. LP-FB: 91.5±14.4, P=0.712). However, the LP-FB cohort reported lower levels of pain (LP-FB: 0.5±1.1 vs. LP-BL: 1.9±2.7, P=0.020) at their latest follow-up. There were no significant differences in complication rates including re-dislocation between cohorts (LP-BL: 2/29 [6.9%] vs. LP-FB: 2/18 [11.1%], P=0.629).

Conclusions

When performed after failed Bankart repair, the LP results in similar postoperative functional outcomes and similar rates of complications and re-dislocations when compared to the primary indication of recurrent glenohumeral instability in the setting of critical bone loss.

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

Background

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

Methods

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

Results

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

Conclusion

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

[Translated article] Correlation between the incidence of rotator cuff lesion in traumatic unilateral anterior glenohumeral dislocation and the contralateral shoulder

INTRODUCTION

Anterior glenohumeral dislocation in patients older than 60 years is related to rotator cuff lesion because of its pre-existing degenerative condition. However, in this age group, the scientific evidence fails to elucidate whether rotator cuff lesions are the cause or consequence of recurrent shoulder instability. The objective of this paper is to describe the prevalence of rotator cuff injuries in a series of consecutive shoulders in patients older than 60 years who suffered a first episode of traumatic glenohumeral dislocation, and its correlation with rotator cuff injuries in both shoulders.

METHODS

Retrospectively, 35 patients over 60 years of age who had a first episode of unilateral traumatic anterior glenohumeral dislocation and who had MRI of both shoulders were studied, evaluating both shoulders with MRI to determine the structural damage correlation of the rotator cuff and long head of the biceps between them.

RESULTS

When assessing the existence of partial or complete injury to the supraspinatus and infraspinatus tendons, the concordance on the affected and healthy sides, we have shown concordant results on both sides in 88.6 and 85.7%, respectively. The Kappa concordance coefficient was 0.72 for supraspinatus and infraspinatus tendons tear. Of the total of 35 cases evaluated, 8 (22.8%) presented at least some alteration in the tendon of the long head of the biceps on the affected side and only one (2.9%) on the healthy side, where the Kappa coefficient of concordance was 0.18. Of the 35 cases evaluated, 9 (25.7%) presented at least some retraction in the tendon of the subscapularis muscle on the affected side, while no participant showed signs of retraction in the tendon of this muscle on the healthy side.

CONCLUSIONS

Our study has found a high correlation of the presence of a postero-superior rotator cuff injury after presenting a glenohumeral dislocation between the shoulder that has suffered the event and the presumably healthy contralateral shoulder. Nevertheless, we have not found this same correlation with subscapularis tendon injury and medial biceps dislocation.

In-Season Management of Shoulder Instability: How to Evaluate, Treat, and Safely Return to Sport

PURPOSE OF REVIEW

Anterior glenohumeral instability is a common injury in contact and collision athletes, and in-season management remains a controversial topic.

RECENT FINDINGS

Several recent studies have examined non-operative and operative management of in-season athletes after instability events. Non-operative treatment is associated with faster return to play and higher rates of recurrent instability. Dislocations and subluxations have similar rates of recurrent instability but non-operatively treated subluxations have a quicker return to play than dislocations. Operative treatment is often a season ending decision but is associated with high rates of return to sport and significantly lower rates of recurrent instability. Indications for in-season operative intervention may include critical glenoid bone loss (>15%), an off-track Hill-Sachs lesion, an acutely reparable bony Bankart lesion, high-risk soft tissue injures such as a humeral avulsion of the glenohumeral ligament or displaced anterior labral periosteal sleeve avulsion, recurrent instability, insufficient time remaining in season to rehabilitate from injury, and inability to successfully return to sport with rehabilitation. It is the role of the team physician to appropriately educate athletes on risks and benefits of operative and non-operative treatment strategies and guide athletes through the shared decision-making process that balances these risks against their long-term health and athletic career goals.

Trends and Projections in Surgical Stabilization of Glenohumeral Instability in the United States from 2009 to 2030: Rise of the Latarjet and Fall of the Open Bankart

INTRODUCTION

Advances in surgical techniques have improved the ability to address recurrent glenohumeral instability via arthroscopic capsulolabral repair and bone restoring procedures such as Latarjet. Given the paucity of studies analyzing temporal trends in surgical management of glenohumeral instability, the purpose of this study was to assess trends in treatment of anterior, posterior, and multidirectional instability over a 10-year period and model projections to 2030.

METHODS

Using IBM Watson Marketscan national database, all patients that underwent glenohumeral instability procedures from 2009 to 2018 were identified. Procedures were identified using common procedural terminology (CPT) codes for open Bankart Repair, Latarjet, anterior bone block, posterior bone block, multidirectional capsular shift, and arthroscopic Bankart procedures. Sample weights provided by the database were utilized to calculate national estimates. The United States (U.S.) Census Bureau annual population data were utilized for calculating incidence. Future projections to 2030 were modeled using Poisson and linear regression.

RESULTS

There were an estimated 446,072 glenohumeral instability cases from 2009-2018. Per capita (per 100,000) incidence remained constant, from 14.8 in 2009 to 14.5 in 2018. Arthroscopic Bankart comprised the highest number of procedures throughout the study period, accounting for 89% of all procedures in 2009 and 93% in 2018. Open Bankart procedures decreased by 65% from 2009 to 2018, while there was a 250% increase in Latarjet procedures over the same period. Patient demographics did not change over the study period, and males aged 18-25 comprised the largest demographic group undergoing anterior instability procedures. Multidirectional instability procedures exhibited the least pronounced gender differences. Future modeling from 2018-2030 projected continued steady rise in arthroscopic Bankart (40,000-49,000 case/yr), rapid growth in Latarjet (1370-4300 cases/yr), and continued decline in open Bankart (1000-250 cases/yr) procedures.

CONCLUSIONS

Arthroscopic Bankart continues to be the most common glenohumeral instability procedure in the U.S. From 2009 to 2018, incidence of open Bankart procedures declined while Latarjet procedures markedly increased. Future projections to 2030 mirrored these findings. These data may provide an enhanced understanding of the evolution of surgical treatment of glenohumeral instability within the U.S. laying the foundation for continued prospective studies into the appropriate indications and advancements in surgical techniques.

Dynamic pediatric shoulder instability: Etiology, pathogenesis and treatment

Dynamic shoulder instability in children or adolescents, whose glenohumeral growth plates are still open, is a rare condition with an etiology that is hard to decipher. Atraumatic and recurrent forms are most common, contrary to adults. Disruptions to capsule and ligament maturation, muscle balance or bone growth can lead to glenohumeral instability. The etiology assessment, which needs to be multidisciplinary in atraumatic forms, aims to collect the medical history, analyze the direction of the instability, determine whether it is voluntary or involuntary, and look for a history of trauma, connective tissue abnormality, psychological disorder, neuromuscular pathology or congenital malformation. The initial treatment is conservative. It requires a multidisciplinary team when the shoulder instability is voluntary. Surgical treatment is reserved for symptomatic forms that do not respond to conservative treatment and have an impact on daily life and/or sports participation after a minimum of 6 months of well-conducted rehabilitation. The results of surgical stabilization mainly depend on the features of the instability, the anatomical structures damaged and the etiology. Episodes of recurrent instability in children/adolescents with open glenohumeral growth plates can fade in adulthood or can get worse with the development of structural damage. Early detection of poor outcomes and suitable treatment will help to limit the occurrence of osteoarthritis in the medium and long term. LEVEL OF EVIDENCE: Expert opinion.

Correlation between the incidence of rotator cuff lesion in traumatic unilateral anterior glenohumeral dislocation and the contralateral shoulder

INTRODUCTION

Anterior glenohumeral dislocation in patients older than 60 years is related to rotator cuff lesion because of its pre-existing degenerative condition. However, in this age group, the scientific evidence fails to elucidate whether rotator cuff lesions are the cause or consequence of recurrent shoulder instability. The objective of this paper is to describe the prevalence of rotator cuff injuries in a series of consecutive shoulders in patients older than 60 years who suffered a first episode of traumatic glenohumeral dislocation, and its correlation with rotator cuff injuries in both shoulders.

METHODS

Retrospectively, 35 patients over 60 years of age who had a first episode of unilateral traumatic anterior glenohumeral dislocation and who had MRI of both shoulders were studied, evaluating both shoulders with MRI to determine the structural damage correlation of the rotator cuff and long head of the biceps between them.

RESULTS

When assessing the existence of partial or complete injury to the supraspinatus and infraspinatus tendons, the concordance on the affected and healthy sides, we have shown concordant results on both sides in 88.6 and 85.7%, respectively. The Kappa concordance coefficient was 0.72 for supraspinatus and infraspinatus tendons tear. Of the total of 35 cases evaluated, 8 (22.8%) presented at least some alteration in the tendon of the long head of the biceps on the affected side and only one (2.9%) on the healthy side, where the Kappa coefficient of concordance was 0.18. Of the 35 cases evaluated, 9 (25.7%) presented at least some retraction in the tendon of the subscapularis muscle on the affected side, while no participant showed signs of retraction in the tendon of this muscle on the healthy side.

CONCLUSIONS

Our study has found a high correlation of the presence of a postero-superior rotator cuff injury after presenting a glenohumeral dislocation between the shoulder that has suffered the event and the presumably healthy contralateral shoulder. Nevertheless, we have not found this same correlation with subscapularis tendon injury and medial biceps dislocation.

Recurrence of glenohumeral instability in patients with isolated rotator cuff repair after a traumatic shoulder dislocation

INTRODUCTION

The primary objective of this study was to assess the incidence of recurrent glenohumeral instability in patients over 40 years with isolated rotator cuff (RC) repair for traumatic shoulder dislocation. The secondary objectives were to identify risk factors for glenohumeral recurrence after RC repair and to describe the causes and incidences of re-intervention.

MATERIALS AND METHODS

In this retrospective cohort study, data of consecutive patients at a single trauma center between January 2014 and July 2019 were reviewed, and 84 patients with a mean age of 57 (range: 40-75) years and follow-up duration of 3.9 (2-6) years were included. The inclusion criteria were as follows: first traumatic anterior shoulder dislocation, reparable RC tear, primary arthroscopic RC repair, no labral or bony Bankart lesion repair, and at least 2 years of follow-up. Patients less than 40 years of age were excluded. Shoulder instability recurrences and surgical reinterventions were reviewed with medical records. Statistical analysis was performed for qualitative variables using the Chi-squared test. Statistical significance was set at P ≤ 0.05.

RESULTS

There was one patient with a redislocation episode (1.2%) at 2.5 years after surgery, who was surgically treated. Age, subscapular tears, bony Bankart injuries, humeral defects, and associated neurological injuries were not risk factors for recurrence in this study. Ten patients (11.9%) required reintervention. Nine patients (10.7%) re-tore their RCs.

CONCLUSIONS

Recurrent glenohumeral instability in active patients over 40 years with isolated RC repair after traumatic shoulder dislocation was infrequent, despite the incidence of significant Hill-Sachs defects, anterior glenoid defects, bipolar bone defects, size of the RC injury, and tendon re-tears. The incidence of re-interventions was 11.9%, with symptomatic RC retear as the main cause.

Posterior shoulder dislocation with associated reverse Hill-Sachs lesion: clinical outcome 10 years after joint-preserving surgery

INTRODUCTION

Posterior shoulder dislocation in association with reverse Hill-Sachs lesion is a rather rare injury. Few studies reporting results after joint-preserving surgery in these cases are available. This current study presents the clinical outcomes 10 years postoperatively.

MATERIALS AND METHODS

In a prospective case series, we operatively treated 12 consecutive patients (all males) after posterior shoulder dislocation with associated reverse Hill-Sachs lesion using joint-preserving techniques. Patients received surgery in a single center between January 2008 and December 2011. The joint-preserving surgical procedure was chosen depending on the defect size and bone quality. The following outcome-measures were analyzed: Constant-Score, DASH-Score, ROWE-Score, and SF-12. Results 1, 5, and 10 years postoperatively were compared.

RESULTS

Out of 12 patients, ten patients (83.3%) were followed-up with a mean follow-up interval of 10.7 years (range 9.3-12.8). The mean patient age at the time of the last follow-up was 51 years (32-66). The outcome scores at the final follow-up were: Constant 92.5 (range 70.0-100), DASH 3.2 (0.0-10.8), ROWE 91.0 (85.0-100), and SF-12 87.8 (77.5-98.3). Clinical results had improved from 1 to 5 years postoperatively and showed a tendency for even further improvement after 10 years.

CONCLUSIONS

Joint-preserving surgical therapy of posterior shoulder dislocation provides excellent results when the morphology of the reverse Hill-Sachs lesion is respected in surgical decision-making.

TRIAL REGISTRATION

223/2012BO2, 02 August 2010.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Shoulder dislocations among high school-aged and college-aged athletes in the United States: an epidemiologic analysis

Hypothesis/Background

Shoulder dislocations are common orthopedic injuries due to the mobile nature of the glenohumeral joint. High school and collegiate athletes are at particularly high risk for sustaining a dislocation event. Despite the prevalence of these injuries, there is a paucity in the literature regarding incidence of sports-related shoulder dislocations and mechanism of injury within these populations. Therefore, the aim of the present study was to (1) determine the incidence rate of shoulder dislocations in high school–aged and collegiate-aged athletes presenting to emergency departments (EDs) in the United States; (2) to determine the most common sports associated with shoulder dislocations; and (3) to compare the current rates and risk factors for shoulder dislocation with previous trends.

Methods

The National Electronic Injury Surveillance System is a statistically validated injury surveillance system that collects data from ED visits as a representative probability sample of hospitals in the United States. We queried the National Electronic Injury Surveillance System for the years 2015-2019 to examine the following variables for sports-related shoulder dislocations: patient age (high school = 13-17 years of age; collegiate = 18-23 years of age), sex, year of admission, and sport type. Using a weighted multiplier, annual incidence rates were estimated based on the US Census estimates and injury rates were compared by sex and age group across the study period.

Results

From 2015 to 2019, there were a total of 1329 athletic-related shoulder dislocations that presented to participating EDs. Of these, 698 (52.5%) shoulder dislocations occurred in collegiate athletes, while 631 (47.5%) occurred in high school athletes. Using weighted and adjusted estimates automatically generated by the National Electronic Injury Surveillance System database, this translates to 89,511 total athletic-related shoulder dislocations across the United States (95% confidence interval lower bound 68,224; 95% confidence interval upper bound 110,798). Male athletes demonstrated a higher proportion of shoulder dislocations (87%) than female athletes (13%). The most common sport-specific mechanisms of traumatic shoulder dislocation were basketball (24.1%), football (21%), soccer (7.1%), baseball (7.1%), and weightlifting (3.3%).

Conclusion

Sports-related shoulder dislocations are frequent in high school–aged and college-aged athletes presenting to the ED. Interventions to reduce incidence of injury should be sport-specific and focus on those participating in contact and noncontact sports. Male athletes have disproportionately higher rates of dislocation. These findings are consistent with the previous epidemiologic trends in the literature that have examined the incidence of shoulder dislocations in this population.

Management of common upper extremity injuries in throwing athletes: a critical review of current outcomes

Given the rising incidence and prevalence of shoulder injuries in throwing athletes, this review aims to evaluate management options and outcomes of common shoulder injuries in overhead throwers. Laxity of the glenohumeral joint is often adaptive for overhead athletes to achieve the velocity necessary to compete in the professional ranks. Surgical repair of the stabilizers of the humeral head-specifically the labrum and rotator cuff-often causes inflammation, scarring, and overtensioning of the glenohumeral joint which lead to poor postoperative performance. Thus, nonsurgical management should be exhausted in this population before considering surgical intervention.

Glenohumeral Joint Instability: A Review of Anatomy, Clinical Presentation, and Imaging

The glenohumeral joint is intrinsically predisposed to instability because of the bony anatomy but maintained in alignment by many important structures, including the glenoid labrum, glenohumeral ligaments (GHLs), and muscles and tendons. Trauma and overuse can damage these stabilizers, which may then lead to subluxation or dislocation and eventually recurrent instability. This is most common in the anterior direction, which has several recognizable patterns of injury on advanced imaging, including humeral Hill Sachs deformities, bony Bankart lesion of the anteroinferior glenoid, soft tissue Bankart lesions, Bankart variant lesions (Perthes and ALPSA lesions), and HAGL/GAGL lesions. Similar reverse lesions are seen, as well as unique posterior lesions, such as Bennett and Kim's lesions. When symptoms of apprehension and instability in more than one direction are seen, one should consider multidirectional instability, which often presents with a patulous joint capsule. Finally, owing to significant impacts of daily activities and quality of life, surgical correction of labral tears, bony Bankart defects, Hill Sachs defects, and capsular laxity, may be considered.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

III (cohort study).

A hybrid open-arthroscopic latarjet coracoid bone-block technique using "HyLa" instrumentation

Latarjet coracoid bone-block is a gold-standard procedure for anteroinferior instability of the shoulder. Nowadays, it can be performed as open surgery or entirely under arthroscopy. The pure arthroscopic technique has the advantage of allowing concomitant intra-articular surgery, but involves a long learning curve. Here we present a hybrid concept using dedicated instrumentation comprising a specific guide with or without arthroscopic step, and notably ensuring the safety and reproducibility of the procedure, whatever the modality. This technique offers an alternative to arthroscopic coracoid bone block, performing the more complex steps as open surgery without major change to Latarjet's original technique, so as to enable concomitant intra-articular surgery if needed while getting around some of the limitations of the purely arthroscopic procedure.

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.

Latarjet procedure for anterior shoulder instability: a 24-year follow-up study

INTRODUCTION

Different surgical techniques (open and arthroscopic) have been described for the treatment of post-traumatic recurrent anterior instability. The aim of the surgery is to restore when possible, normal shoulder anatomy by repairing the underlying pathology responsible for the instability. Sometimes other surgical techniques are indicated. The purpose of this retrospective study was to investigate the long-term clinical and radiographic results and complications of the open Latarjet procedure after a minimum follow-up of 24 years.

MATERIALS AND METHODS

A retrospective study was performed for 67 patients treated with an open Latarjet procedure in a single center. Forty of these 67 patients returned for follow-up evaluation and clinical/radiological examination during the year 2018, having had a minimum of 24-year follow-up. Clinical outcomes were analyzed using two functional scores, in addition to the ROM and strength assessment. Radiographic evaluation included several views (AP views in neutral, internal and external rotation and a comparative Bernageau view) RESULTS: A total of 40 patients underwent an open Latarjet procedure. All the patients were avaible for follow-up at an average of 25.6 years. Clinically, no patient reported any episode of dislocation at the time of follow-up. The mean Rowe score and the Walch-Duplay score were 84.5 (range 45-100) and 83.5 (range 55-100), respectively. Non-union/fibrous union was reported in 12.5% of cases, partial resorption of the graft was found in 7.5% of cases, while total resorption was found in 5% of cases. Osteoarthritis was identified in 52.5% (21) of the patients.

CONCLUSIONS

This long-term follow-up study demonstrated that the open Latarjet procedure is a safe and reliable technique for recurrent anterior shoulder instability. The Latarjet procedure provides good long-term stability although associated with a slight limitation in external rotation.

LEVEL OF EVIDENCE

Level III; retrospective cohort comparison; treatment study.

The impact of age on 30-day complications following shoulder instability surgery

HYPOTHESIS

The purpose of this study was to evaluate short-term outcomes including medical complications, overnight admission, and 30-day readmission with regard to patient age at the time of shoulder instability surgery.

METHODS

Patients undergoing surgery for glenohumeral instability were collected from the National Surgical Quality Improvement Program between the years of 2005 and 2016. These patients were separated into cohorts of younger than 25 years, 25-34 years, and older than 34 years. Medical complications, hospital admission, and 30-day readmission were compared using multivariate analysis.

RESULTS

Of the 5449 patients included, there were 2035 (37.0%) patients younger than 25 years, 1815 (33.0%) between 25 and 34 years, and 1649 (30.0%) 35 and older. Overall, 81.7% of patients underwent an arthroscopic Bankart repair, 12.6% of patients underwent an open Bankart repair, and 5.7% of patients underwent a Latarjet-Bristow procedure. The risk of 30-day readmission increased with age, ranging from 0.24% for <25 years old to 0.92% for 35 years and older (P = .040). Operative duration greater than 60 minutes (odds ratio [OR] 1.76; P = .001), duration greater than 90 minutes (OR 3.58; P < .001), and American Society of Anesthesiologists class III and IV (OR 1.80; P = .001) were associated with increased risk of overnight hospital stay. Compared with arthroscopic Bankart repair, the Latarjet-Bristow procedure was associated with increased total complications (OR 3.30; P = .021), overnight hospital stay (OR 4.64; P < .001), and 30-day readmission (OR 3.39; P = .013).

CONCLUSION

This study demonstrates that even in the relatively young and healthy shoulder instability patient cohort, patients older than 25 years are almost 4 times more likely to experience a complication. Additionally, Latarjet-Bristow procedures are 3-4 times more likely to experience a complication or readmission than other shoulder instability procedures.

Double-loaded suture anchors in the treatment of anteroinferior glenohumeral instability

Hypothesis

The purpose of this study was to determine the clinical outcomes of arthroscopic labral repair for anteroinferior glenohumeral instability with the use of double-loaded suture anchors.

Methods

This study evaluated a series of consecutive patients treated after the senior author changed from single- to double-loaded suture anchors for the treatment of anteroinferior glenohumeral instability with a minimum follow-up period of 2 years. We collected the following outcomes at final follow-up: visual analog scale pain score, Simple Shoulder Test score, American Shoulder and Elbow Surgeons score, and instability recurrence data.

Results

A total of 41 consecutive patients underwent arthroscopic labral repair with double-loaded anchors, of whom 30 (71%) were able to be contacted at a minimum of 2 years postoperatively. These patients included 4 contact or collision athletes (13%). The patients had an average of 12 ± 13 prior dislocations over an average period of 56 ± 57 months preoperatively. Mean glenoid bone loss measured 16% ± 10%, and 67% (18 of 27 patients) had glenoid bone loss ≥ 13.5%. Intraoperatively, 3.2 ± 0.4 anchors were used. No posterior repairs or remplissage procedures were performed. At an average of 6.7 ± 2.7 years' follow-up, the visual analog scale pain score was 0.8 ± 1.4; Simple Shoulder Test score, 11 ± 2; and American Shoulder and Elbow Surgeons score, 90 ± 14. Patients with bone loss < 13.5% had a 0% redislocation rate and 11% subluxation rate, whereas those with bone loss ≥ 13.5% had a 6% reoperation rate, 22% redislocation rate, and 22% subluxation rate.

Conclusion

Arthroscopic labral repair with double-loaded anchors provides satisfactory clinical results at early to mid-term outcome assessment when glenoid bone loss is <13.5%.

Revision anterior glenohumeral instability: is arthroscopic treatment an option?

Background

The purpose of this study was to determine the short-term outcomes for patients who underwent revision surgery for shoulder instability, including both revision arthroscopic repair and Latarjet.

Methods

This study included patients who underwent revision of a prior arthroscopic labral repair to arthroscopic labral repair or Latarjet at our institution from 2012 to 2017. After collection of preoperative demographic data, preoperative 3-dimensional imaging was reviewed to determine percent glenoid bone loss (%GBL) and to determine whether each shoulder was on-track or off-track. Patients were contacted to obtain postoperative patient-reported outcome metrics including visual analog scale pain, Simple Shoulder Test, American Shoulder and Elbow Surgeons scores, and instability recurrence (full dislocation, subluxation, or subjective apprehension) data at a minimum of 2 years postoperatively.

Results

Of 62 patients who met criteria, 45 patients were able to be contacted. Of them, 21 underwent revision arthroscopy and 24 underwent a Latarjet procedure. In the revision arthroscopy group, 5 of 15 had %GBL >20% and 4 of 21 were contact athletes. In the Latarjet group, 11 of 22 had %GBL >20% and 5 of 24 were contact athletes. Of 21 revision arthroscopy patients, 8 underwent concomitant remplissage. Eight of 21 patients in the revision arthroscopy group and 7 of 21 patients in the Latarjet group reported instability postoperatively. Three of 21 patients in the revision arthroscopy group and 2 of 21 patients in the Latarjet group reported full dislocations postoperatively. Zero patients in the revision arthroscopy group and 1 of 21 patients in the Latarjet group underwent reoperation.

Conclusion

Our results suggest that both revision Latarjet and arthroscopic stabilization can be of benefit in select circumstances. However, in revision settings, postoperative instability symptoms are common with both procedures.

Comprehensive review of the physical exam for glenohumeral instability

Glenohumeral instability is a common pathology of the shoulder joint, especially among young athletes. Despite advancements in technology and the widespread use of diagnostic imaging, a careful history and physical examination still remain the cornerstone of diagnosing patients with shoulder instability. Due to the involvement of many static and dynamic stabilizers, proficient physical examination can be challenging. With a systematic approach to clinical evaluation, the clinician can recognize characteristic patterns of relevant signs and symptoms and make an accurate diagnosis.

A systematic review of patient-reported outcome measures used in shoulder instability research

BACKGROUND

Shoulder instability is extremely common, with various outcome scores used to assess its progression after treatment. This review was performed to identify the scores most commonly used and to evaluate them according to the 4 core domains of shoulder trials (according to the Core Outcome Measures in Effectiveness Trials [COMET] initiative) and their respective psychometric qualities.

METHODS

A systematic review of the literature of 3 databases (MEDLINE, Embase, PubMed) was undertaken. Studies were identified using eligibility criteria and critically appraised by 2 authors. Data were extracted using an a priori template. Outcome scores were identified and assessed regarding COMET domain inclusion and their psychometric properties.

RESULTS

The most frequently used scores were the Rowe (58%), Constant (33%), Western Ontario Shoulder Instability Index (WOSI; 24%), and American Shoulder and Elbow Surgeons (23%) scores. The majority of outcome scores assessed pain and all assessed physical functioning. Quality of life and a global assessment of treatment success were rarely incorporated. No single outcome score considered all core COMET domains. The WOSI was the most acceptable measure of those assessed with respect to its validity, reliability, and responsiveness.

CONCLUSIONS

The WOSI incorporated 3 of the 4 core domains for shoulder trials (pain, physical functioning, and health-related quality of life). It had the most psychometric testing of the identified scores, confirming its reliability, validity, and responsiveness in the setting of shoulder instability. We recommend its use in this setting; however, it should be supplemented with additional outcome scores, such as the University of California-Los Angeles score, to cover all of the core COMET domains.

Glenohumeral translation during active external rotation with the shoulder abducted in cases with glenohumeral instability: a 4-dimensional computed tomography analysis

BACKGROUND

Although glenohumeral instability is common, the mechanism of instability remains unclear. The purpose of this study was to quantitatively evaluate humeral head translation during active external rotation with abduction in patients with glenohumeral instability by use of 4-dimensional computed tomography scans.

METHODS

Ten patients with unilateral glenohumeral instability with a positive fulcrum test were prospectively included in this study. Sequential computed tomography of bilateral shoulders during active external rotation at 90° of shoulder abduction was performed for 6 seconds at 5 frames per second. The 3-dimensional positions of the humeral head center in the anteroposterior, superoinferior, and mediolateral directions were calculated at 0°, 20°, 40°, 60°, and maximum shoulder abduction-external rotation from the starting position. Translation of the humeral head center from the starting position was evaluated using Dunnett multiple-comparison tests, and the differences between the affected and intact shoulders were assessed using Wilcoxon signed rank tests.

RESULTS

The humeral head center translated posteriorly, inferiorly, and medially during glenohumeral external rotation with the shoulder in the abducted position on the intact side. However, the affected humeral head showed significantly less posterior translation (P = .028), greater inferior translation (P = .047), and less medial translation (P = .037) than the contralateral side.

CONCLUSIONS

This study indicated that dysfunction of the anterior band of the inferior glenohumeral ligament causes decreased posterior, increased inferior, and decreased medial translation of the humeral head during active shoulder abduction-external rotation.

Etiology of Shoulder Arthritis in Young Patients

The manifestation of glenohumeral arthritis in the young adult is a devastating occurrence that can be difficult to manage. This review details the many underlying etiologies including genetic causes, congenital abnormalities, glenohumeral instability, posttraumatic lesions, postcapsulorraphy arthropathy, osteonecrosis, intraarticular pain pump postoperative use, radiofrequency/thermal capsulorraphy treatments, septic arthritis/infection, and inflammatory arthropathies. Although each of these potential causes have been well-studied, their contributions to the development of glenohumeral arthritis in the young person has not been described extensively.

Analysis of failures after the Bristow-Latarjet procedure for recurrent shoulder instability

PURPOSE

Despite good clinical results and low recurrence rates, post-operative complications of coracoid process transfer procedures are not well understood. This study aims to evaluate the underlying failure mechanism in cases requiring major open revision surgery after prior Bristow or Latarjet stabilization.

METHODS

Between January 2006 and January 2017, 26 patients underwent major open revision after primary Bristow or Latarjet procedure. Clinical notes and radiographic images were retrospectively reviewed for all cases to determine underlying pathology. Choice of treatment and clinical and radiographic outcome were similarly reported for all cases.

RESULTS

The underlying failure mechanism was associated with non-union in 42.3%, resorption in 23.1%, graft malpositioning in 15.4%, and trauma or graft fracture in 19.2% of cases. Although none of the patients reported any dislocations, mean subjective shoulder score was 60.2% and WOSI scores averaged 709.3 points at final follow-up. Radiographic signs of deteriorating degenerative arthritis were seen in 34.6%.

CONCLUSION

Graft non-union resulting in recurrent instability was the main indication for open revision surgery after Bristow or Latarjet procedure, followed by resorption, malpositioning, and graft fracture in this retrospective case series. Revision surgery consisted of a structural iliac crest bone graft in the majority of cases. Clinical and radiographic outcomes are predictably variable in this population of multioperated patients.

Feasibility of using an inversion-recovery ultrashort echo time (UTE) sequence for quantification of glenoid bone loss

OBJECTIVE

To utilize the 3D inversion recovery prepared ultrashort echo time with cones readout (IR-UTE-Cones) MRI technique for direct imaging of lamellar bone with comparison to the gold standard of computed tomography (CT).

MATERIALS AND METHODS

CT and MRI was performed on 11 shoulder specimens and three patients. Five specimens had imaging performed before and after glenoid fracture (osteotomy). 2D and 3D volume-rendered CT images were reconstructed and conventional T1-weighted and 3D IR-UTE-Cones MRI techniques were performed. Glenoid widths and defects were independently measured by two readers using the circle method. Measurements were compared with those made from 3D CT datasets. Paired-sample Student's t tests and intraclass correlation coefficients were performed. In addition, 2D CT and 3D IR-UTE-Cones MRI datasets were linearly registered, digitally overlaid, and compared in consensus by these two readers.

RESULTS

Compared with the reference standard (3D CT), glenoid bone diameter measurements made on 2D CT and 3D IR-UTE-Cones were not significantly different for either reader, whereas T1-weighted images underestimated the diameter (mean difference of 0.18 cm, p = 0.003 and 0.16 cm, p = 0.022 for readers 1 and 2, respectively). However, mean margin of error for measuring glenoid bone loss was small for all modalities (range, 1.46-3.92%). All measured ICCs were near perfect. Digitally registered 2D CT and 3D IR-UTE-Cones MRI datasets yielded essentially perfect congruity between the two modalities.

CONCLUSIONS

The 3D IR-UTE-Cones MRI technique selectively visualizes lamellar bone, produces similar contrast to 2D CT imaging, and compares favorably to measurements made using 2D and 3D CT.

Surgical stabilization for first-time shoulder dislocators: a multicenter analysis

BACKGROUND

Anterior shoulder dislocations in young patients are associated with high rates of recurrent instability. Although some surgeons advocate for surgical stabilization after a single dislocation event in this population, there is sparse research evaluating surgical treatment for first-time dislocators.

METHODS

Patients undergoing surgical stabilization for anterior shoulder instability were prospectively enrolled at multiple institutions from 2015-2017 and stratified by number of dislocations before surgery. Demographic data, preoperative patient-reported outcomes, imaging findings, surgical findings, and procedures performed were compared between groups. Analysis of variance, χ², and multivariate logistic regression were used for statistical analysis.

RESULTS

The study included 172 patients (mean age, 25.3 years; 79.1% male patients) for analysis (58 patients with 1 dislocation, 69 with 2-5 dislocations, 45 with >5 dislocations). There were no intergroup differences in demographic characteristics, preoperative patient-reported outcomes, or physical examination findings. Preoperative imaging revealed increased glenoid bone loss in patients with multiple dislocation events (P = .043). Intraoperatively, recurrent dislocators were more likely to have bony Bankart lesions (odds ratio [OR], 3.26; P = .024) and biceps pathology (OR, 6.27; P = .013). First-time dislocators more frequently underwent arthroscopic Bankart repair and/or capsular plication (OR, 2.22; P = .016), while recurrent dislocators were more likely to undergo open Bristow-Latarjet procedures (OR, 2.80; P = .049) and surgical treatment for biceps pathology (OR, 5.03; P = .032).

CONCLUSIONS

First-time shoulder dislocators who undergo stabilization are more likely to undergo an arthroscopic procedure and less likely to have bone loss or biceps pathology compared with recurrent dislocators. Future studies are needed to ascertain long-term outcomes of surgical stabilization based on preoperative dislocation events.

Bilateral Anterior Shoulder Dislocation in the Elderly - A Case Report and Review of the Literature

Introduction

Bilateral shoulder dislocations are rare and a diagnostic as well as a therapeutic challenge.

Case Report

We report the case of a 67-year-old male who fell while skiing and suffered a bilateral anterior shoulder dislocation associated with a four-part proximal humerus fracture on the left side and an osseous avulsion of the rotator cuff, a Pulley lesion, and a Hill-Sachs lesion on the right side. In addition, we searched the PubMed database using the terms "bilateral shoulder dislocation" and also "bilateral glenohumeral dislocation". All retrieved matches were browsed for reports of bilateral anterior shoulder dislocations in patients aged 40 years or older. We identified and analyzed 35 case reports, including our own, regarding 20 male and 15 female patients with an average age of 58.9 years (female: 59.2 years, male: 58.6 years).

Conclusion

Elderly patients with a bilateral shoulder dislocation are at special risk for late diagnosis (five of 35 cases were not detected on the same day, but up to nine months later), concomitant pathologies (proximal humerus fractures were present in 19 cases; rotator cuff pathologies in seven cases), and insufficient diagnostic soft-tissue imaging (only four cases performed ultrasound/magnetic resonance imaging). Our reported case assembles a variety of possible concomitant pathologies. Through careful and comprehensive diagnostics all accompanying lesions were detected and subsequently addressed. The patient's outcome shows that even in older patients with a combination of various bony, cartilaginous, muscular and ligamentous pathologies, good-to-excellent post-reductive and post-operative results are possible if diagnostics are comprehensive and treatment is prompt.

Treatment of The Posterior Unstable Shoulder

BACKGROUND

It is estimated that approximately 5% of glenohumeral instabilities are posterior. There are a number of controversies regarding therapeutic approaches for these patients.

METHODS

We analyse the main surgery alternatives for the treatment of the posterior shoulder instability. We did a research of the publications related with posterior glenohumeral instability.

RESULTS

There are conservative and surgical treatment options. Conservative treatment has positive results in most patients, with around 65 to 80% of cases showing recurrent posterior dislocation. There are multiple surgical techniques, both open and arthroscopic, for the treatment of posterior glenohumeral instability. There are procedures that aim to repair bone defects and others that aim to repair soft tissues and capsulolabral injuries. The treatment should be planned according to each case on an individual basis according to the patient characteristics and the injury type. Surgical treatment is indicated in patients with functional limitations arising from instability and/or pain that have not improved with rehabilitation treatment. The indications for arthroscopic treatment are recurrent posterior subluxation caused by injury of the labrum or the capsulolabral complex; recurrent posterior subluxation caused by capsuloligamentous laxity or capsular redundancy; and multidirectional instability with posterior instability as a primary component. Arthroscopic assessment will help identify potential injuries associated with posterior instability such as bone lesions or defects and lesions or defects of soft tissues. The main indications for open surgery would be in cases of Hill Sachs lesions or broad reverse Bankart lesions not accessible by arthroscopy. We indicated non-anatomical techniques (McLaughlin or its modifications) for reverse Hill-Sachs lesions with impairment of the articular surface between 20% and 50%. Disimpaction of the fracture and placement of bone graft (allograft or autograft) is a suitable treatment for acute lesions that do not exceed 50% of the articular surface and with articular cartilage in good condition. Reconstruction with allograft may be useful in lesions affecting up to 50% of the humeral surface and should be considered when there is a situation of non-viable cartilage at the fracture site. For defects greater than 50% of the articular surface or in the case of dislocations over 6 months in duration where there is poor bone quality, some authors advocate substitution techniques as a treatment of choice. The main techniques for treating glenoid bone defects are posterior bone block and posterior opening osteotomy of the glenoid.

CONCLUSIONS

The treatment of the posterior glenohumeral instability has to be individualized based on the patient´s injuries, medical history, clinical exam and goals. The most important complications in the treatment of posterior glenohumeral instability are recurrent instability, avascular necrosis and osteoarthritis.

3D-CT of the shoulder in patients with glenohumeral instability

OBJECTIVE

To determine whether 3D-MR osseous reformats of the shoulder are equivalent to 3D-CT osseous reformats in patients with glenohumeral instability.

MATERIALS AND METHODS

Patients with glenohumeral instability, who were to be imaged with both CT and MRI, were prospectively selected. CT and MR were performed within 24 h of one another on 12 shoulders. Each MR study included an axial 3D isotropic VIBE sequence. The image data from the isotropic VIBE sequence were post-processed using subtraction and 3D software. CT data were post-processed using 3D software. The following measurements were obtained for both 3D-CT and 3D-MR post-processed images: height and width of the humeral head and glenoid, Hill-Sachs size and percent humeral head loss (if present), size of glenoid bone loss and percent glenoid bone loss (if present). Paired t-tests and two one-sided tests for equivalence were used to assess the differences between imaging modalities and equivalence.

RESULTS

The measurement differences from the 3D-CT and 3D-MR post-processed images were not statistically significant. The measurement differences for humeral height, glenoid height and glenoid width were borderline statistically significant; however, using any adjustment for multiple comparisons, this failed to be significant. Using an equivalence margin of 1 mm for measurements and 1.5% for percent bone loss, the 3D-MR and 3D-CT post-processed images were equivalent.

CONCLUSION

Three-dimensional-MR osseous models of the shoulder using a 3D isotropic VIBE sequence were equivalent to 3D-CT osseous models, and the differences between modalities were not statistically significant.

Radiographic sclerotic contour loss in the identification of glenoid bone loss

PURPOSE

Quantification of glenoid bone loss guides surgical management in the setting of anterior shoulder instability. Glenoid defects resulting in ≥20 % articular area loss require bony reconstruction. The objective of this study was to evaluate the utility of sclerotic glenoid contour loss on true anteroposterior radiography in the detection of varying quantities of simulated glenoid bone loss using a cadaveric model.

METHODS

Eight cadaveric scapulae with full radiographic sclerotic contour were osteotomized to produce glenoid surface area reductions of 10-50 %. Radiography was performed initially and following each osteotomy, and assessed by an orthopedic surgeon and radiologist twice. Quantity of glenoid loss was compared using Fisher's exact test. Sensitivity, specificity, and reliability analyses were performed.

RESULTS

On the first radiographic review, sclerotic contour loss was detected in 6 out of 8 scapulae with 50 % area loss, but only 1 out of 8 scapulae with 20 % area loss. There was a significantly higher proportion of radiographs containing sclerotic contour loss for defects with 50 % area loss compared to those with 0-25 % loss (p ≤ 0.02). In the detection of ≥20 % area loss, sclerotic contour loss had a sensitivity of 33-43 % and specificity of 88-100 %. Moderate inter-observer reliability (Cohen's kappa value of 0.42-0.53) and intra-observer reliability (kappa value of 0.46-0.58) were found.

CONCLUSION

Radiographic sclerotic contour loss is commonly observed in radiographs of scapulae with 40-50 % glenoid area loss and less often with smaller lesions. However, this finding lacks utility in discerning specific quantifications of glenoid bone loss. In a clinical setting, sclerotic contour loss suggests the presence of a large glenoid defect that may require bony reconstruction. However, an intact sclerotic contour does not rule out significant bone loss.

Mid-range shoulder instability modeled as a cam-follower mechanism

In this paper, we model a simplified glenohumeral joint as a cam-follower mechanism during experimental simulated dislocation. Thus, humeral head trajectory and translational forces are predicted using only contact surface geometry and compressive forces as function inputs. We demonstrate this new interpretation of glenohumeral stability and verify the accuracy of the method by physically testing a custom-molded, idealized shoulder model and comparing data to the output of the 2D mathematical model. Comparison of translational forces between experimental and mathematical approaches resulted in r(2) of 0.88 and 0.90 for the small and large humeral head sizes, respectively. Comparison of the lateral displacement resulted in r(2) of 0.99 and 0.98 for the small and larger humeral head sizes, respectively. Comparing translational forces between experiments and the mathematical model when varying the compressive force to 30 N, 60 N, and 90 N resulted in r(2) of 0.90, 0.82, and 0.89, respectively. The preliminary success of this study is motivation to introduce the effects of soft tissue such as cartilage and validation with a cadaver model. The use of simple mathematical models such as this aid in the set-up and understanding of experiments in stability research and avoid unnecessary depletion of cadaveric resources.

Differences in glenohumeral joint morphology between patients with anterior shoulder instability and healthy, uninjured volunteers

BACKGROUND

Traumatic glenohumeral joint (GHJ) dislocations are common, resulting in significant shoulder disability and pain. Previous research indicates that bony morphology is associated with an increased risk of injury in other joints (eg, the knee), but the extent to which bony morphology is associated with traumatic GHJ dislocation is unknown. This study assessed GHJ morphology in patients with anterior GHJ instability and in a control population of healthy volunteers.

METHODS

Bilateral computed tomography scans were used to measure GHJ morphology in both shoulders of 11 patients with instability and 11 control subjects. Specific outcome measures included the glenoid radius of curvature (ROC) in the anterior/posterior (A/P) and superior/inferior (S/I) directions, humeral head ROC, A/P and S/I conformity index, and A/P and S/I stability angle.

RESULTS

Compared with the control subjects, the glenoid of the instability the injured shoulder in patients with instability was flatter (ie, higher ROC) in the A/P (P = .001) and S/I (P = .01) directions and this finding was also true for uninjured, contralateral shoulder (A/P: P = .01, S/I: P = .03). No differences in GHJ morphology were detected between the instability patients' injured and contralateral shoulders (P > .07). Similarly, no differences in GHJ morphology were detected between the control subjects' dominant and nondominant shoulders (P > .51).

CONCLUSIONS

There are significant differences in GHJ morphology between healthy control subjects and both shoulders (injured and uninjured, contralateral) of patients diagnosed with anterior instability after GHJ dislocation. These findings are important clinically because they suggest that glenoid morphology may influence the risk of GHJ dislocation.

Shoulder instability in the military

Shoulder instability is common in military populations, and this demographic represents individuals at high risk for recurrence. Surgical management is often indicated, especially in high-demand young individuals, and provides a predictable return to military duties. Accurate recognition of glenoid bone loss and other associated anatomic lesions is of importance for appropriate selection between arthroscopic capsulolabral repair and bony reconstruction procedures. A thorough understanding of underlying pathology, diagnostic testing, and available treatment options provides for optimal care of the unstable shoulder.

Management of bone loss in glenohumeral instability

This review discusses the evaluation and management of bone loss in glenohumeral instability. The glenohumeral joint may experience a dislocation or subluxation associated with traumatic injury or through repetitive atraumatic events. Nearly 62% of cases with recurrent dislocation have both Hill-Sachs and bony Bankart defects. Treatment of unstable bone defects may require soft-tissue repair, bone grafting, or both, depending on the size and nature of the defects. The most common treatment is isolated soft-tissue repair, leaving the bone defects untreated, although emerging evidence supports directly addressing these bony defects.

Scapulothoracic muscle activity and recruitment timing in patients with shoulder impingement symptoms and glenohumeral instability

BACKGROUND

Various studies have investigated scapulothoracic muscle activity and recruitment patterns in relation to shoulder complaints in different populations, but a consensus review is lacking.

HYPOTHESIS/PURPOSE

To systematically review the state of the art regarding scapulothoracic muscle activity and recruitment timing in subjects with shoulder pain compared to pain free controls.

STUDY DESIGN

Systematic review.

METHODS

The search for relevant articles was performed in Pubmed and Web of Science, including Web of Knowledge, using key words related to shoulder pain, scapulothoracic muscle activity or recruitment timing. Articles were included till November 2012. Case-control studies concerning the scapulothoracic region and muscle recruitment using electromyography (EMG) were included. Articles regarding rotator cuff muscles or neck-shoulder pathologies or studies handling a treatment outcome, were excluded. The methodological quality of the articles was assessed using appropriate risk of bias criteria for case-control studies.

RESULTS

A total of 12 articles were included in the systematic review, containing patients with Shoulder Impingement Syndrome (SIS) or glenohumeral instability. In patients with SIS 3 out of 6 articles showed increased upper trapezius muscle (UT) activity, 3 out of 5 studies showed decreased lower trapezius muscle (LT) activity and 3 out of 5 articles showed decreased serratus anterior muscle (SA) activity. Patients with glenohumeral instability showed contradictory results on scapulothoracic muscle activity patterns. In both SIS and glenohumeral instability patients, no consensus was found on muscle recruitment timing.

CONCLUSION

Patients with SIS and glenohumeral instability display numerous variations in scapulothoracic muscle activity compared to healthy controls. In the SIS-group, the LT and SA muscle activity is decreased. In addition, the UT muscle activity is increased among the SIS patients, whereas no clear change is seen among patients with glenohumeral instability. Although the scapulothoracic muscle activity changed, no consensus could be made regarding muscle recruitment timing.

Spectrum of magnetic resonance imaging findings in clinical glenohumeral instability

The glenohumeral joint is the most commonly dislocated joint in the body, and anterior instability is the most common type of shoulder instability. Depending on the etiology and the age of the patient, there may be associated injuries, for example, to the anterior-inferior labro-ligamentous structures (in young individuals with traumatic instability) or to the bony components (commoner in the elderly), which are best visualized using MRI and MR arthrography. Anterior instability is associated with a Bankart lesion and its variants and abnormalities of the anterior band of the inferior glenohumeral ligament (IGHL), whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesions. Cases of multidirectional instability often have no labral pathology on imaging but show specific osseous changes including increased chondrolabral retroversion. This article reviews the relevant anatomy in brief and describes the MRI findings in each type, with the imaging features of the common abnormalities.