History of Shoulder Instability and Subsequent Injury During Four Years of Follow-up A Survival Analysis
ABSTRACT Little is known about the risk factors for glenohumeral joint instability. We hypothesized that a prior history of instability would be a significant risk factor for subsequent injury.
We conducted a prospective cohort study over a four-year period within a high-risk group of young athletes to address the research hypothesis. Subjects were freshmen entering the U.S. Military Academy in June of 2006. Part of the baseline assessment included documenting a prior history of glenohumeral instability on entry into the study. All subjects were followed for subsequent glenohumeral joint instability events until graduation in May of 2010. The primary outcome of interest in this study was time to glenohumeral instability event during the follow-up period. We examined injury outcomes, looking for any instability, anterior instability, and posterior instability events. Cox proportional-hazards regression models were used to analyze the data.
Among the 714 subjects, eight shoulders were excluded from the analyses due to prior surgical stabilization, leaving 1420 shoulders, of which 126 had a self-reported prior history of instability. There were forty-six (thirty-nine anterior and seven posterior) acute instability events documented in the cohort during the follow-up period. Subjects with a prior history of instability were over five times (p < 0.001) more likely to sustain an acute (anterior or posterior) instability event during the follow-up period. Subjects with a history of instability were also 5.6 times (p < 0.001) more likely to experience a subsequent anterior instability event and 4.6 times (p = 0.068) more likely to experience a posterior instability event during follow-up. Similar results were observed in multivariable models after controlling for the influence of demographic and baseline physical examination findings.
Despite meeting the rigorous physical induction standards for military service, subjects with a prior history of glenohumeral joint instability were approximately five times more likely to experience a subsequent instability event, regardless of direction, within this high-risk athletic population.
Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.
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ABSTRACT: Background: The arthroscopic Latarjet procedure combines the benefits of arthroscopic surgery with the low rate of recurrent instability associated with the Latarjet procedure. Only short-term outcomes after arthroscopic Latarjet procedure have been reported. Purpose: To evaluate the rate of recurrent instability and patient outcomes a minimum of 5 years after stabilization performed with the arthroscopic Latarjet procedure. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent the arthroscopic Latarjet procedure before June 2008 completed a questionnaire to determine whether they had experienced a dislocation, subluxation, or further surgery. The patients also completed the Western Ontario Shoulder Instability Index (WOSI). Results: A total of 62 of 87 patients (64/89 shoulders) were contacted for follow-up. Mean follow-up time was 76.4 months (range, 61.2-100.7 months). No patients had reported a dislocation since their surgery. One patient reported having subluxations since the surgery. Thus, 1 patient (1.59%) had recurrent instability after the procedure. The mean standard deviation aggregate WOSI score was 90.6% +/- 9.4%. Mean WOSI domain scores were as follows: Physical Symptoms, 90.1% +/- 8.7%; Sports/Recreation/Work, 90.3% +/- 12.9%; Lifestyle, 93.7% +/- 9.8%; and Emotions, 88.7% +/- 17.3%. Conclusion: The rate of recurrent instability after arthroscopic Latarjet procedure is low in this series of patients with a minimum 5-year follow-up. Patient outcomes as measured by the WOSI are good.The American Journal of Sports Medicine 08/2014; 42(11). DOI:10.1177/0363546514544682 · 4.70 Impact Factor
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ABSTRACT: While anterior glenohumeral instability has been shown to be common in young athletes, the risk factors for injury are poorly understood.09/2014; 42(11). DOI:10.1177/0363546514551149
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ABSTRACT: BACKGROUND:While posterior glenohumeral instability is becoming increasingly common among young athletes, little is known of the risk factors for injury. PURPOSE:To determine the modifiable and nonmodifiable risk factors for posterior shoulder instability in a high-risk cohort. STUDY DESIGN:Case-control study (prognosis); Level of evidence, 2. METHODS:A prospective cohort study in which 714 young athletes were followed from June 2006 through May 2010 was conducted. Baseline testing included a subjective history of instability, instability testing by a sports medicine fellowship-trained orthopaedic surgeon, range of motion, strength measurement with a handheld dynamometer, and bilateral noncontrast magnetic resonance imaging of the shoulder. A musculoskeletal radiologist measured glenoid version, height, depth, rotator interval (RI) height, RI width, RI area, and RI index. Participants were followed to document all acute posterior shoulder instability events during the 4-year follow-up period. The time to the posterior shoulder instability event during the follow-up period was the primary outcome of interest. Univariate and multivariable Cox proportional hazards regression models were used to analyze the data. RESULTS:Complete data on 714 participants were obtained. During the 4-year surveillance period, 46 shoulders sustained documented glenohumeral instability events, of which only 7 were posterior in direction. The baseline factors that were associated with subsequent posterior instability during follow-up were increased glenoid retroversion (P < .0001), increased external rotation strength in adduction (P = .029) and at 45° of abduction (P = .015), and increased internal rotation strength in adduction (P = .038). CONCLUSION:This is the largest known prospective study to follow healthy participants in the development of posterior shoulder instability. Posterior instability represents 10% of all instability events. The most significant risk factor was increased glenoid retroversion. While increased internal/external strength was also associated with subsequent instability, it is unclear whether these strength differences are causative or reactive to the difference in glenoid anatomy. This work confirms that increased glenoid retroversion is a significant prospective risk factor for posterior instability.The American Journal of Sports Medicine 08/2013; 41(11). DOI:10.1177/0363546513501508 · 4.70 Impact Factor