Pathomechanics of acquired shoulder instability: a basic science perspective

Evaluating the Athlete with Instability from on the Field to in the Clinic

Shoulder glenohumeral joint dislocations and subluxations are a relatively common injury among athletic populations. Evaluating the patient both on the field initially and through early recovery helps to determine the best treatment strategies and predict the natural history of each unique injury.

Retrospective analysis of decision-making in post-traumatic posterior shoulder instability

PURPOSE

This study aims to assess the clinical outcomes in the management of post-traumatic posterior shoulder instability (PSI) with a focus on the decision-making process for operative and conservative treatments.

INTRODUCTION

PSI can result from traumatic events, impacting a patient's quality of life. This study delves to better indicate decision-making for operative indication of post-traumatic PSI patients.

METHODS

Patients who sustained posterior shoulder dislocations were selected from a single surgeon's database within a five-year period. Cases of degenerative or genetically caused PSI were excluded, resulting in a cohort of 28. Patients were initially managed conservatively but indicated for surgery if they were unable to actively stabilize the shoulder or exhibited bony or cartilage defects confirmed through imaging. If conservative treatment did not yield significant improvements, it was classified as a failure, and operative intervention was recommended. The WOSI Score, ROM, and X-ray were employed to evaluate the success of treatment.

RESULTS

Out of the 28 patients, 11 received conservative, seven immediate surgeries, and ten transitioned from conservative to operative treatment. The overall success rate showed 25 good to excellent results. In the persistent conservative treatment group, the initial WOSI score was significantly lower compared to the operative group.

CONCLUSION

This study suggests that post-traumatic PSI can be successfully managed conservatively with initial low clinical symptoms (low WOSI score) and in the absence of absolute indications for operative treatment. When surgery is necessary, arthroscopic procedures proved effective in achieving good to excellent results in 16 out of 17 cases.

Analysis of Rotator Cuff Muscle Injury on the Drawing Side of the Recurve Bow: A Finite Element Method

Background

This study establishes the shoulder model on the drawing side of recurve archers by the finite element method and finds out the stress changes on the rotator cuff muscles in the position of the humerus and scapula under different stages of special techniques. The aim of this study is to investigate the mechanism of rotator cuff damage on a recurve archer's drawing arm.

Methods

A 22-year-old healthy male's shoulder CT and MRI data were collected, and the drawing side shoulder joint finite element model was constructed, which contains the structure of the shoulder blades, clavicle, humerus, supraspinatus, infraspinatus, teres minor, and subscapularis. The humerus on the drawing arm was simulated to raising the bow, drawing, holding, and releasing on the scapula plane, and stress changes in rotator cuff muscles are analyzed.

Results

The peak stress on the infraspinatus increased slowly, and from the start of raising the bow to hold and release, the stress peak increased from 0.007 MPa to 0.009 MPa. The peak stress on teres minor rises slowly from 0.003 MPa at the start of raising the bow to 0.010 MPa at the moment of releasing. The peak stress in the subscapularis increased from 0.096 MPa to 0.163 MPa between the start of raising the bow and releasing. The peak stress on the supraspinatus varied greatly, and from the start of raising the bow to the start of drawing, the stress peak increased markedly from 1.159 MPa to 1.395 MPa. Subsequently, the stress peak immediately decreased to 1.257 MPa at the start of holding and then increased to 1.532 MPa at releasing.

Conclusion

The position of the humerus and scapula would change with the different stages of special techniques. It causes stress changes in the rotator cuff muscles, and when the stress accumulates over time, the shoulder 5on the drawing side will gradually become injured and dysfunctional. In combination with the depth of the structural site and the surrounding structural features, corrective exercises can be used to prevent injury to the rotator cuff muscles.

Bankart Repair With Subscapularis Augmentation in Athletes With Shoulder Hyperlaxity

PURPOSE

The purpose of this study was to demonstrate that arthroscopic Bankart repair with associated arthroscopic subscapularis augmentation (ASA) could be a valid surgical option in the treatment of anterior shoulder instability, in collision and contact sports athletes, affected by shoulder hyperlaxity.

METHODS

In total, 591 arthroscopic Bankart repairs plus ASA were performed in 6 shoulder centers from 2009 to 2017. Inclusion criteria were the following: collision and contact sports activities, recurrent anterior instability associated with hyperlaxity and glenoid bone loss (GBL) < 15%. Exclusion criteria were GBL > 15%, voluntary instability, multidirectional instability, pre-existing osteoarthritis and throwing athletes. The minimum follow-up was 24 months. Hyperlaxity was clinically evaluated according to Neer and Coudane-Walch tests. Before surgery, all patients underwent magnetic resonance imaging and computed tomography scanning. Pico area method was used to assess the percentage of GBL. Patients were operated on by 6 surgeons, and their functional outcomes were evaluated by 2 independent observers. The Western Ontario Shoulder Instability Index (WOSI), Rowe, American Shoulder and Elbow Surgeons (ASES) scores were used to assess results.

RESULTS

Overall, 397 patients with evidence of shoulder hyperlaxity (positive sulcus sign in ER1 position and Coudane-Walch test > 85°) met all inclusion criteria. The mean WOSI score was 321; the mean Rowe score rose from 68.5 to 92.5 (P = .037), and the ASES score rose from 71.5 to 97.4 (P = .041). Seven patients (1.6%) had atraumatic redislocation, and 9 patients (2.2%) had post-traumatic redislocation. At final follow-up the mean functional deficit of external rotation was 15° with the arm in adduction (ER1 position) and 10° in abduction (ER2 position).

CONCLUSIONS

The Bankart repair plus ASA has been demonstrated to be safe and effective for restoring joint stability in patients practicing collision and contact sports or affected by chronic anterior shoulder instability associated with GBL (<15%) and hyperlaxity, without compromising external rotation.

LEVEL OF EVIDENCE

Level IV, case series.

Influence of Glenoid Labral Bumper Height and Capsular Volume on Clinical Outcomes After Arthroscopic Bankart Repair as Assessed With Serial CT Arthrogram: Can Anterior-Inferior Volume Fraction Be a Prognostic Factor?

BACKGROUND

Arthroscopic labral repair combined with capsular plication decreases joint volume and restores glenoid labral bumper height; thus, the procedure helps decrease capsular redundancy. However, the decreased volume and restored glenoid labral bumper height could change over time, which could influence the outcome of the operation.

PURPOSE

To (1) measure glenoid labral bumper height and capsular volume quantitatively in serial computed tomography arthrography (CTA) and evaluate the relationship between bumper height and joint volume and (2) compare the difference in bumper height and joint volume between groups with and without apprehension after arthroscopic Bankart repair.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients who had undergone arthroscopic Bankart repair between January 2012 and June 2016, and were assessed by CTA 3 to 6 months and 12 to 18 months after the operation were included. An image reconstruction program (3-dimensional slicer) was used to calculate inferior, anterior-inferior, and posterior-inferior joint volumes; the ratio of the anterior-inferior volume to the inferior volume was defined as the anterior-inferior volume fraction (VF_AI). We also measured glenoid labral bumper height at the 5-, 4-, and 3-o'clock positions.

RESULTS

A total of 50 patients were enrolled as study participants (mean age, 25.2 ± 9.29 years). Of these, 10 patients had either redislocation or apprehension, and 40 patients had neither. A significant correlation was observed between 5-o'clock glenoid labral bumper height and VF_AI on early CTA (3-6 months) and late CTA (12-18 months) (early CTA: Pearson coefficient, -0.335, P = .040; late CTA: Pearson coefficient, -0.468, P = .003). VF_AI at the early CTA was 42.20 ± 10.15 in the group with apprehension and 33.49 ± 9.66 in the group without apprehension; a significant difference was observed. VF_AI at the late CTA was 45.84 ± 11.97 in the group with apprehension and 37.65 ± 9.70 in the group without apprehension and thus showed a significant difference between the 2 groups. However, the 3-, 4-, and 5-o'clock glenoid labral bumper heights on early and late CTAs did not show a statistically significant difference between the 2 groups.

CONCLUSION

Early postoperative VF_AI is related to postoperative apprehension and redislocation and might be reduced by increasing the 5-o'clock glenoid labral bumper height.

Evidence-Based Review of Clinical Diagnostic Tests and Predictive Clinical Tests That Evaluate Response to Conservative Rehabilitation for Posterior Glenohumeral Instability: A Systematic Review

Context:

Posterior glenohumeral instability is poorly understood and can be challenging to recognize and evaluate. Using evidence-based clinical and predictive tests can assist clinicians in appropriate assessment and management.

Objective:

To review evidence-based clinical diagnostic tests for posterior glenohumeral instability and predictive tests that identify responders to conservative management.

Data Sources:

A comprehensive electronic bibliographic search was conducted using Embase, Ovid MEDLINE, PEDro, and CINAHL databases from their date of inception to February 2017.

Study Selection:

Studies were included for further review if they (1) reported on clinical diagnostic tests for posterior or posteroinferior instability of the glenohumeral joint, (2) assessed predictive clinical tests for posterior instability of the glenohumeral joint, and (3) were in English.

Study Design:

Systematic review.

Level of Evidence:

Level 4.

Data Extraction:

Data were extracted from the studies by 2 independent reviewers and included patient demographics and characteristics, index/reference test details (name and description of test), findings, and data available to calculate psychometric properties.

Results:

Five diagnostic and 2 predictive studies were selected for review. There was weak evidence for the use of the jerk test, Kim test, posterior impingement sign, and O’Brien test as stand-alone clinical tests for identifying posterior instability. Additionally, there was weak evidence to support the use of the painless jerk test and the hand squeeze sign as predictive tests for responders to conservative management. These findings are attributed to study design limitations, including small and/or nonrepresentative samples.

Conclusion:

Clustering of thorough history and physical examination findings, including the aforementioned tests, may identify those with posterior glenohumeral instability and assist in developing management strategies.

Painful posterior shoulder instability: Anticipating and preventing failure. A study in 25 patients

BACKGROUND

Painful posterior shoulder instability (PPSI) is the least common of the three clinical patterns of posterior shoulder instability. PPSI is defined as pain combined with anatomical evidence of posterior instability but no instability events.

MATERIAL AND METHOD

We studied a multicentre cohort of 25 patients with PPSI; 23 were identified retrospectively and had a follow-up of at least 2 years and 2 patients were included prospectively. Most patients engaged in sports.

RESULTS

All 25 patients underwent surgery, which usually consisted in arthroscopic capsulo-labral reconstruction. The outcome was excellent in 43% of patients; another 43% had improvements but reported persistent pain. The pain remained unchanged or worsened in the remaining 14% of patients. Causes of failure consisted of a missed diagnosis of shoulder osteoarthritis with posterior subluxation, technical errors, and postoperative complications. The main cause of incomplete improvement with persistent pain was presence of cartilage damage.

CONCLUSION

Outcomes were excellent in patients who were free of cartilage damage, bony abnormalities associated with posterior instability (reverse Hill-Sachs lesion, erosion or fracture of the posterior glenoid), technical errors, and postoperative complications.

Pitch-side management of acute shoulder dislocations: a conceptual review

The shoulder, specifically the glenohumeral joint, by virtue of its anatomical characteristics and biomechanics confers a large range of movement, which ultimately results in a joint that is inherently prone to becoming unstable. The incidence of acute traumatic shoulder dislocation varies within the sporting environment, commonly occurring following direct trauma. Anterior dislocations account for nearly 90% of all dislocations. While most are referred and managed in the emergency department, pitch-side relocation by experienced clinicians does occur prior to referral. The aim of this study was to delineate a guideline specifically for the pitch-side management of this common injury. A literature search of PubMed and Medline using the keywords ‘prehospital’, ‘pitch-side’, ‘shoulder dislocation’ and ‘reduction’ or ‘relocation technique’ was performed, and the available literature was reviewed and collated. Articles focusing on reduction techniques were then reviewed, with particular consideration on their applicability to a pitch-side setting. While studies exist that compare and contrast examination and reduction techniques, most are based in a hospital setting. To date, there is no standardised management protocol published for the initial management of an anterior dislocated shoulder in a pitch-side setting. This article addresses this discrepancy and proposes a structured, algorithmic approach to the pitch-side management of a shoulder dislocation. The article addresses factors to consider in a pitch-side setting, suitable techniques and postreduction care. While a systematic approach has been delineated in this article, we recommend those pitch-side medical practitioners who provide this form of support should have attended appropriate training and ensure adequate malpractice cover.

Differential expression of extracellular matrix genes in glenohumeral capsule of shoulder instability patients

Anterior shoulder instability is a common orthopedic problem. After a traumatic shoulder dislocation, patients present a plastic deformation of the capsule. The shoulder instability biology remains poorly understood. We evaluated the expression of genes that encode the cartilage oligomeric matrix protein (COMP), fibronectin 1 (FN1), tenascin C (TNC) and tenascin XB (TNXB) in the glenohumeral capsule of anterior shoulder instability patients and controls. Moreover, we investigated the associations between gene expression and clinical parameters. The gene expression was evaluated by quantitative reverse transcription-polymerase chain reaction in the antero-inferior (macroscopically injured region), antero-superior and posterior regions of the capsule of 29 patients with shoulder instability and 8 controls. COMP expression was reduced and FN1 and TNC expression was increased in the antero-inferior capsule region of cases compared to controls (p < 0.05). TNC expression was increased in the posterior capsule portion of shoulder instability patients (p = 0.022). COMP expression was reduced in the antero-inferior region compared to the posterior region of shoulder instability patients (p = 0.007). In the antero-inferior region, FN1 expression was increased in the capsule of patients with more than one year of symptoms (p = 0.003) and with recurrent dislocations (p = 0.004) compared with controls. FN1 and TNXB expression was correlated with the duration of symptoms in the posterior region (p < 0.05). Thus, COMP, FN1, TNC and TNXB expression was altered across the capsule of shoulder instability patients. Dislocation episodes modify FN1, TNC and TNXB expression in the injured tissue. COMP altered expression may be associated with capsule integrity after shoulder dislocation, particularly in the macroscopically injured portion.

Evidence-based conservative rehabilitation for posterior glenohumeral instability: A systematic review

STUDY DESIGN

Systematic review.

OBJECTIVES

To identify the best evidenced-based approach for the conservative rehabilitation of patients with posterior glenohumeral instability.

BACKGROUND

Posterior glenohumeral instability is more common than previously thought. Proper management is imperative to control symptoms and maximize function.

METHODS

We conducted an electronic search, up to November 2014, for English-language studies involving rehabilitation of posterior shoulder instability. A manual search of reference lists of included articles and previously published reviews was also performed.

RESULTS

Five studies met the review inclusion criteria. Most studies demonstrated that rotator cuff and posterior deltoid strengthening could reduce instability recurrence and pain, and increase function, mainly in those with atraumatic posterior instability without previous surgery. These studies were mainly case series or retrospective designs.

CONCLUSIONS

Rotator cuff and posterior deltoid strengthening may help with symptom-management and functioning in those with posterior glenohumeral instability. Further research is needed to detect statistically significant outcomes from conservative treatment.

LEVEL OF EVIDENCE

Therapy, Level 3.

Expression analysis of genes involved in collagen cross-linking and its regulation in traumatic anterior shoulder instability

The molecular alterations involved in the capsule deformation presented in shoulder instability patients are poorly understood. Increased TGFβ1 acts as a signal for production of matrix macromolecules by fibrogenic cells at joint injury sites. TGFβ1, through its receptor TGFβR1, regulates genes involved in collagen cross-linking, such as LOX, PLOD1, and PLOD2. We evaluated TGFβ1, TGFβR1, LOX, PLOD1, and PLOD2 gene expression in the antero-inferior (macroscopically injured region), antero-superior and posterior regions of the glenohumeral capsule of 29 shoulder instability patients and eight controls. We observed that PLOD2 expression was increased in the anterior-inferior capsule region of the patients compared to controls. LOX expression tended to be increased in the posterior portion of patients. Patients with recurrent shoulder dislocation presented upregulation of TGFβR1 in the antero-inferior capsule portion and of PLOD2 in the posterior region. Conversely, LOX was increased in the posterior portion of the capsule of patients with a single shoulder dislocation episode. In the antero-inferior, LOX expression was inversely correlated and TGFβR1 was directly correlated with the duration of symptoms. In the posterior region, PLOD2, TGFβ1, and TGFβR1 were directly correlated with the duration of symptoms. In conclusion, PLOD2 expression was increased in the macroscopically injured region of the capsule of patients. Upregulation of TGFβ1, TGFβR1, and PLOD2 seems to be related with the maintenance of disease symptoms, especially in the posterior region. LOX upregulation seems to occur only in the initial phase of the affection. Therefore, TGFβ1, TGFβR1, LOX, and PLOD2 may play a role in shoulder instability.

Profile of collagen gene expression in the glenohumeral capsule of patients with traumatic anterior instability of the shoulder

Objective

To evaluate the expression of the genes COL1A1, COL1A2, COL3A1 and COL5A1 in the glenohumeral capsule of patients with traumatic anterior instability of the shoulder.

Methods

Samples from the glenohumeral capsule of 18 patients with traumatic anterior instability of the shoulder were evaluated. Male patients with a positive grip test and a Bankart lesion seen on magnetic resonance imaging were included. All the patients had suffered more than one episode of shoulder dislocation. Samples were collected from the injured glenohumeral capsule (anteroinferior region) and from the macroscopically unaffected region (anterosuperior region) of each patient. The expression of collagen genes was evaluated using the polymerase chain reaction after reverse transcription with quantitative analysis (qRT-PCR).

Results

The expression of COL1A1, COL1A2 and COL3A1 did not differ between the two regions of the shoulder capsule. However, it was observed that the expression of COL5A1 was significantly lower in the anteroinferior region than in the anterosuperior region (median ± interquartile range: 0.057 ± 0.052 vs. 0.155 ± 0.398; p = 0.028) of the glenohumeral capsule.

Conclusion

The affected region of the glenohumeral capsule in patients with shoulder instability presented reduced expression of COL5A1.

Factors affecting capsular volume changes and association with outcomes after Bankart repair and capsular shift

BACKGROUND

Capsular laxity is a main contributing factor in recurrent shoulder instability and is suggested to be correlated with increased capsular volume. Arthroscopic capsular shift combined with Bankart repair can reduce the capsular volume and reinforce the redundant capsule; however, as the capsuloligamentous structure has viscoelastic properties, it is possible for the shifted and tensioned capsule of the glenohumeral joint to slowly stretch out again over time, resulting in an increase in capsular volume.

PURPOSE

To analyze changes in capsular volume of the glenohumeral joint over time after arthroscopic Bankart repair and capsular shift, the factors associated with these changes, and their relevance to outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Included in this study were 105 patients (mean age, 25.8 ± 8.2 years) who underwent arthroscopic Bankart repair and capsular shift for anterior shoulder instability and computed tomography arthrography (CTA) at 3 months and 1 year postoperatively and whose various functional outcomes were evaluated preoperatively and at the last follow-up (>12 months). Among these patients, 27 also had preoperative CTA. These 27 patients were used to make comparisons between preoperative and 3-month postoperative CTA measurements, and all 105 patients were used for all other comparisons. Two raters measured the separate anterior and posterior capsular volume and cross-sectional area at the 5-o'clock position using 3-dimensional (3D) Slicer software. These measurements were subsequently adjusted for each glenoid size. The changes in capsular volume and cross-sectional area at the 5-o'clock position over time, the factors related to higher change in anterior capsular volume, and their correlation with outcomes were evaluated.

RESULTS

Three months postoperatively, the total and anterior capsular volume and anterior cross-sectional area significantly decreased; however, these values increased again at 1 year postoperatively (all P < .01). The inter- and intraobserver reliabilities of the measurements were excellent (interclass correlation coefficient = 0.717-0.945). Female sex, being an elite athlete, and more dislocations before surgery were related to a higher increase in anterior capsular volume at 1 year (all P < .05). Eight patients had redislocation, and 18 exhibited positive apprehension test postoperatively, and these patients showed significantly higher increases in anterior and total capsular volume at 1 year than did those without redislocation or positive apprehension sign (all P < .01). However, with the exception of Rowe score, a higher increase in anterior capsular volume was not related to functional outcome measures.

CONCLUSION

Surgeons should be aware of the re-increase in anterior capsular volume or restretching trait of the anterior capsule over time, even after successful arthroscopic Bankart repair and capsular shift. In this study, women, elite athletes, and those with frequent dislocations were at high risk of capsular restretching. An increase in capsular volume was related to redislocation and positive apprehension sign as well as with Rowe score.

Gene expression analysis in patients with traumatic anterior shoulder instability suggests deregulation of collagen genes

Shoulder dislocation occurs in 1-2% of the population. Capsular deformation is a key factor in shoulder dislocation; however, little is known about capsule biology. We evaluated, for the first time in literature, the expression of COL1A1, COL1A2, COL3A1 and COL5A1 in the antero-inferior, antero-superior and posterior regions of the glenohumeral capsule of 31 patients with anterior shoulder instability and eight controls. The expression of collagen genes was evaluated by quantitative reverse transcription-PCR. The expression of COL1A1, COL3A1 and the ratio of COL1A1/COL1A2 were increased in all three portions of the capsule in patients compared to controls (p < 0.05). COL1A2 expression was upregulated in the antero-superior and posterior sites of the capsule of patients (p < 0.05). The ratio of COL1A2/COL3A1 expression was reduced in capsule antero-inferior and posterior sites of patients compared to controls (p < 0.05). In the capsule antero-inferior site of patients, the ratios of COL1A1/COL5A1, CO1A2/COL5A1 and COL3A1/COL5A1 expression were increased (p < 0.05). In patients, COL1A1/COL5A1 was also increased in the posterior site (p < 0.05). We found deregulated expression of collagen genes across the capsule of shoulder instability patients. These molecular alterations may lead to modifications of collagen fibril structure and impairment of the healing process, possibly with a role in capsular deformation.

Identification of suitable reference genes for gene expression studies of shoulder instability

Shoulder instability is a common shoulder injury, and patients present with plastic deformation of the glenohumeral capsule. Gene expression analysis may be a useful tool for increasing the general understanding of capsule deformation, and reverse-transcription quantitative polymerase chain reaction (RT-qPCR) has become an effective method for such studies. Although RT-qPCR is highly sensitive and specific, it requires the use of suitable reference genes for data normalization to guarantee meaningful and reproducible results. In the present study, we evaluated the suitability of a set of reference genes using samples from the glenohumeral capsules of individuals with and without shoulder instability. We analyzed the expression of six commonly used reference genes (ACTB, B2M, GAPDH, HPRT1, TBP and TFRC) in the antero-inferior, antero-superior and posterior portions of the glenohumeral capsules of cases and controls. The stability of the candidate reference gene expression was determined using four software packages: NormFinder, geNorm, BestKeeper and DataAssist. Overall, HPRT1 was the best single reference gene, and HPRT1 and B2M composed the best pair of reference genes from different analysis groups, including simultaneous analysis of all tissue samples. GenEx software was used to identify the optimal number of reference genes to be used for normalization and demonstrated that the accumulated standard deviation resulting from the use of 2 reference genes was similar to that resulting from the use of 3 or more reference genes. To identify the optimal combination of reference genes, we evaluated the expression of COL1A1. Although the use of different reference gene combinations yielded variable normalized quantities, the relative quantities within sample groups were similar and confirmed that no obvious differences were observed when using 2, 3 or 4 reference genes. Consequently, the use of 2 stable reference genes for normalization, especially HPRT1 and B2M, is a reliable method for evaluating gene expression by RT-qPCR.

Evaluation and management of posterior shoulder instability

CONTEXT

Posterior shoulder instability is a commonly misdiagnosed disorder in many competitive athletes.

TYPE OF STUDY

Clinical review.

EVIDENCE ACQUISITION

Relevant studies on posterior shoulder instability from 1950 to 2010 in PubMed and Cochrane databases were reviewed.

RESULTS

A total of 107 studies were reviewed.

CONCLUSION

Patients who have undergone at least 6 months of physical therapy and still experience instability symptoms should be considered for surgical stabilization directed at their underlying pathology.

Prolonged immobilization in abduction and neutral rotation for a first-episode anterior shoulder dislocation

STUDY DESIGN

Case report.

BACKGROUND

Patients who sustain first-episode anterior glenohumeral dislocations are at risk to develop chronic glenohumeral instability. Current treatment options after an initial anterior glenohumeral dislocation include immediate surgery, delayed surgery, or conservative interventions such as immobilization and strengthening exercises. Duration of immobilization is variable among formal studies. Recent research suggests that typical immobilization positions may not allow adequate healing and in fact may promote glenohumeral joint instability.

CASE DESCRIPTION

The patient was a 19-year-old male who sustained a first-episode anterior glenohumeral dislocation during athletic activity. Physical therapy management included a longer-than-typical period of immobilization and protected activity to allow for more complete healing. The shoulder abduction and neutral rotation immobilization position used with this patient may increase healing of structures that influence stability of the shoulder

OUTCOMES

At 13 weeks after the dislocation, the patient had full active and passive range of motion, near normal strength, and no complaints of pain or instability. At a 20-month follow-up the patient had resumed full activities of daily living including recreational sports without symptoms of instability.

DISCUSSION

Conservative intervention options for first-episode anterior shoulder dislocations need further study. Immobilization and protected activity periods should be adequate to allow for complete healing. The optimal positions for immobilization should be determined and implemented.