History of Shoulder Instability and Subsequent Injury During Four Years of Follow-up A Survival Analysis

Department of Orthopedic Surgery, Keller Army Hospital, United States Military Academy, 900 Washington Road, West Point, NY 10996. E-mail address for K.L. Cameron: .
The Journal of Bone and Joint Surgery (Impact Factor: 5.28). 03/2013; 95(5):439-45. DOI: 10.2106/JBJS.L.00252
Source: PubMed


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.

Download full-text


Available from: Kenneth L Cameron, Oct 29, 2015
  • [Show abstract] [Hide abstract]
    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 · 4.36 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Thorough evaluation of the athlete with persistent shoulder instability and appropriate use of imaging modalities, such as 3-dimensional computed tomography, can help quantify the severity of bony deficiency. Based on obtained imaging and examination, surgical and nonsurgical methods can be considered. In many situations both the humeral- and glenoid-sided bone loss must be addressed. Depending on the extent of bone loss, athletic demands, and surgeon experience, arthroscopic or open surgical options can provide shoulder stability and return athletes to their prior level of activity.
    Clinics in sports medicine 10/2013; 32(4):741-760. DOI:10.1016/j.csm.2013.07.008 · 1.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Unlabelled: Ice hockey is a high contact sport where players are inherently at an increased risk for traumatic and time-loss injury. With its increasing popularity and high incidence of injury, further research is necessary to understand the risks and injuries associated with the sport and to develop performance-based outcome measures to guide return to play. This review, tailored to the practicing sports medicine team physician, focuses on the stepwise identification, treatment, time loss, return to play and subsequent risk of injury for the most common areas of injury: the head, shoulder, hip and knee. Injuries were categorised into upper and lower extremity with an emphasis on glenohumeral and acromioclavicular joint injuries, femoroacetabular impingement, medial collateral ligament tears, and high ankle sprains. With return to play a primary goal for these high-level athletes, recovery in ice hockey becomes a complex issue with efficient protocols tailored to the requirements of the sport vital to the athlete and clinician alike. By reviewing the treatments and sport-specific care, athletes can be better managed with the ultimate goal of returning to their preinjury level of play. Level of evidence: Level IV.
    British Journal of Sports Medicine 11/2013; 48(1). DOI:10.1136/bjsports-2013-093020 · 5.03 Impact Factor
Show more