Michele L. Duffey

The Incidence and Characteristics of Shoulder Instability at the United States Military Academy

Background The literature provides little information detailing the incidence of traumatic shoulder instability in young, healthy athletes. Hypothesis Shoulder instability is common in young athletes. Study Design Descriptive epidemiologic study. Methods We prospectively captured all traumatic shoulder instability events at the United States Military Academy between September 1, 2004, and May 31, 2005. Throughout this period, all new traumatic shoulder instability events were evaluated with physical examination, plain radiographs, and magnetic resonance imaging. Instability events were classified according to direction, chronicity, and type (subluxation or dislocation). Subject demographics, mechanism of injury, and sport were evaluated. Results Among 4141 students, 117 experienced new traumatic shoulder instability events during the study period; 11 experienced multiple events. The mean age of these 117 subjects was 20.0 years; 101 students were men (86.3%), and 16 were women (13.7%). The 1-year incidence proportion was 2.8%. The male incidence proportion was 2.9% and the female incidence proportion was 2.5%. Eighteen events were dislocations (15.4%), and 99 were subluxations (84.6%). Of the 99 subluxations, 45 (45.5%) were primary events, while 54 (54.5%) were recurrent. Of the 18 dislocations, 12 (66.7%) were primary events, while 6 (33.3%) were recurrent. The majority of the 117 events were anterior in nature (80.3%), while 12 (10.3%) were posterior, and 11 (9.4%) were multidirectional. Forty-four percent (43.6%) of the instability events experienced were as a result of contact injuries, while 41.0% were a result of noncontact injuries, including 9 subluxations caused by missed punches during boxing; information was unavailable for the remaining 15%. Conclusion Glenohumeral instability is a common injury in this population, with subluxations comprising 85% of instability events.

Pathoanatomy of first-time, traumatic, anterior glenohumeral subluxation events.

BACKGROUND Relative to dislocations, glenohumeral subluxation events have received little attention in the literature, despite a high incidence in young athletes. The pathoanatomy of first-time, traumatic, anterior subluxation events has not been defined, to our knowledge. METHODS As part of a prospective evaluation of all cases of shoulder instability sustained during one academic year in a closed cohort of military academy cadets, a total of thirty-eight first-time, traumatic, anterior glenohumeral subluxation events were documented. Clinical subluxation events were defined as incomplete instability events that did not require a manual reduction maneuver. Twenty-seven of those events were evaluated with plain radiographs and magnetic resonance imaging within two weeks after the injury and constitute the cohort studied. Magnetic resonance imaging studies were independently evaluated by a musculoskeletal radiologist blinded to the clinical history. Arthroscopic findings were available for the fourteen patients who underwent arthroscopic surgery. RESULTS Of the twenty-seven patients who sustained a first-time, traumatic, anterior subluxation, twenty-two were male and five were female, and their mean age was twenty years. Plain radiographs revealed three osseous Bankart lesions and two Hill-Sachs lesions. Magnetic resonance imaging revealed a Bankart lesion in twenty-six of the twenty-seven patients and a Hill-Sachs lesion in twenty-five of the twenty-seven patients. Of the fourteen patients who underwent surgery, thirteen had a Bankart lesion noted during the procedure. Of the thirteen patients who chose nonoperative management, four experienced recurrent instability. Two of the thirteen patients left the academy for nonmedical reasons and were lost to follow-up. The remaining seven patients continued on active-duty service and had not sought care for a recurrent instability event at the time of writing. CONCLUSIONS First-time, traumatic, anterior subluxation events result in a high rate of labral and Hill-Sachs lesions. These findings suggest that clinical subluxation events encompass a broad spectrum of incomplete events, including complete separations of the articular surfaces with spontaneous reduction. A high index of suspicion for this injury in young athletes is warranted, and magnetic resonance imaging may reveal a high rate of pathologic changes, suggesting that a complete, transient luxation of the glenohumeral joint has occurred.

Association of Generalized Joint Hypermobility With a History of Glenohumeral Joint Instability

CONTEXT Little is known about the relationship among sex, generalized joint hypermobility, and glenohumeral joint instability. OBJECTIVE To examine the relationship among sex, generalized joint hypermobility scores, and a history of glenohumeral joint instability within a young, physically active cohort and to describe the incidence of generalized joint hypermobility within this population. DESIGN Cross-sectional cohort study. SETTING United States Military Academy at West Point, New York. PATIENTS OR OTHER PARTICIPANTS Of the 1311 members of the entering freshman class of 2010, 1050 (80%) agreed to participate. MAIN OUTCOME MEASURE(S) Generalized joint hypermobility was assessed using the Beighton Scale. A history of glenohumeral joint instability was identified via a baseline questionnaire. RESULTS Most participants (78%) had no signs of generalized joint hypermobility. Only 11 volunteers (1.5%) had Beighton Scale scores of 4 or greater. Logistic regression analysis revealed a relationship between generalized joint hypermobility and a history of glenohumeral joint instability (P = .023). When sex and race were controlled, those with a total Beighton Scale score of >or=2 were nearly 2.5 times as likely (odds ratio = 2.48, 95% confidence interval = 1.19, 5.20, P = .016) to have reported a history of glenohumeral joint instability. A relationship was observed between sex and nearly all individual Beighton Scale items. Although women had higher total Beighton Scale scores than men, sex (P = .658) and race (P = .410) were not related to a history of glenohumeral joint instability when other variables in the model were controlled. CONCLUSIONS In these participants, generalized joint hypermobility and a history of glenohumeral joint instability were associated.

Patellar Tendon Versus Hamstring Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial Using Similar Femoral and Tibial Fixation Methods

Background Controversy remains over the most appropriate graft for anterior cruciate ligament reconstruction. Hypothesis There is no significant difference in outcomes after 4-strand hamstring and patellar tendon autograft anterior cruciate ligament reconstructions using similar fixation techniques. Study Design Randomized controlled trial; Level of evidence, 1. Methods Between August 2000 and May 2003, 64 Keller Army Hospital patients with complete anterior cruciate ligament tears were randomized to hamstring (n = 32) or patellar tendon (n = 32) autograft anterior cruciate ligament reconstruction. Operative graft fixation and rehabilitative techniques were the same for both groups. Follow-up assessments included the Single Assessment Numeric Evaluation score, Lysholm score, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score. Postoperative radiographs were analyzed for tunnel location and orientation. Results Eleven women and 53 men were randomized. Eighty-three percent of the patients (53 of 64) had follow-up of greater than 2 years, or to the point of graft rupture or removal (average follow-up, 36 months). Four hamstring grafts (12.5%) and three patellar tendon grafts (9.4%) (P = .71) ruptured. One deep infection in a hamstring graft patient necessitated graft removal. Forty-five of the 56 patients with intact grafts had greater than 2-year follow-up. Patients with patellar tendon grafts had greater Tegner activity scores (P = .04). Single Assessment Numeric Evaluation scores were 88.5 (95% confidence interval: 83.1, 93.8) and 90.1 (95% confidence interval: 85.2, 96.1) for the hamstring and patellar tendon groups, respectively (P = .53). Lysholm scores were 90.3 (95% confidence interval: 84.4, 96.1) and 90.4 (95% confidence interval: 84.5, 96.3) for the hamstring and patellar tendon groups, respectively (P = .97). There were no significant differences in knee laxity, kneeling pain, isokinetic peak torque, International Knee Documentation Committee score, or Knee Injury and Osteoarthritis Outcome Scores. Postoperative graft rupture correlated with more horizontal tibial tunnel orientation. Conclusion Hamstring and patellar tendon autografts provide similar objective, subjective, and functional outcomes when assessed at least 2 years after anterior cruciate ligament reconstruction.

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

BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.

Clinical descriptive measures of shoulder range of motion for a healthy, young and physically active cohort

BackgroundThe objective of this innovative research study was to describe clinical shoulder complex range of motion (ROM) measures for a young, healthy, and physically active population. This investigation represents a cross-sectional experiment conducted at a military academy-based sports medicine center. Military cadets with no history of shoulder complex injury were assessed within two months of enrollment in the academy; 548 men (18.8 ± 1.0 yr, 75.2 ± 12.2 kg, 178.3 ± 7.4 cm) and 74 women (18.7 ± 0.9 yr, 63.2 ± 8.9 kg, 165.2 ± 6.9 cm) participated. Descriptive measures included cross-body adduction (CAD), flexion (FLX), external rotation (ER0) with the shoulder complex in adduction and elbow flexed to 90°, internal and external rotation (IR, ER) with the shoulder complex at 90° of abduction and elbow flexed to 90° as well as arc (ARC) of IR-ER using standardized clinical quantification techniques. Bilateral and sex differences were evaluated using dependent and independent t-tests, respectively. Percentiles by arm dominance and sex were also calculated for all ROM measures.ResultsData were normally distributed. Active and passive ROM measures indicated significant bilateral differences (P < 0.05) except for ARC. Sex differences (P < 0.05) were noted for active and passive CAD, FLX and ER0 for the dominant arm as well as active and passive CAD, FLX and ARC for the non-dominant arm.ConclusionsThese original data provide descriptive measures for shoulder complex ROM excursions, assisting sports medicine practitioners in potentially identifying clinical deficiencies and functional outcomes following shoulder injury.

Isometric Shoulder Strength Reference Values for Physically Active Collegiate Males and Females

Background: It is common clinical practice to assess muscle strength during examination of patients following shoulder injury or surgery. Strength comparisons are often made between the patient’s injured and uninjured shoulders, with the uninjured side used as a reference without regard to upper extremity dominance. Despite the importance of strength measurements, little is known about expected normal baselines of the uninjured shoulder. The purpose of this study was to report normative values for isometric shoulder strength for physically active college-age men and women without history of shoulder injury. Methods: University students—546 males (18.8 ± 1.0 years, 75.3 ± 12.2 kg) and 73 females (18.7 ± 0.9 years, 62.6 ± 7.0 kg)—underwent thorough shoulder evaluations by an orthopaedic surgeon and completed bilateral isometric strength measurements with a handheld dynamometer. Variables measured included internal rotation, external rotation, abduction, supine internal rotation and external rotation at 45°, and lower trapezius in prone flexion. Results: Significant differences were found between the dominant and nondominant shoulder for internal rotation, internal rotation at 45°, abduction, and prone flexion in males and in internal rotation at 45° and prone flexion for females (P ≤ 0.01).

Physical examination findings in young athletes correlate with history of shoulder instability.

The goal of this study was to evaluate physical examination findings in a healthy cohort and determine potential correlations with a history of shoulder instability. A cross-sectional analysis was performed using the baseline data for an ongoing prospective cohort study to examine the risk factors for shoulder instability. A complete history of shoulder instability events was obtained, and a blinded physical examination was performed. The cohort comprised 711 patients (627 men, 84 women) with a mean age of 18.8 years. A total of 100 patients had a history of shoulder instability. Patients with a history of instability were more likely to have increased posterior translation (P=.010), positive apprehension sign (P=.003), positive relocation sign (P=.007), and sulcus sign (P=.017).

Military movement training program improves jump-landing mechanics associated with anterior cruciate ligament injury risk.

As part of the physical education program at the United States Military Academy, all cadets complete a movement training course designed to develop skills and improve performance in military-related physical tasks as well as obstacle navigation. The purpose of this study was to determine if completion of this course would also result in changes in jump-landing technique that reduce the risk of anterior cruciate ligament (ACL) injury. Analysis of landing mechanics on a two-footed jump landing from a height of 30 cm with a three-dimensional motion capture system synchronized with two force plates revealed both positive and negative changes. Video assessment using the Landing Error Scoring System (LESS) revealed an overall improved landing technique (p=.001) when compared to baseline assessments. The studied military movement course appears to elicit mixed but overall improved lower extremity jump-landing mechanics associated with risk for ACL injury.

Implementation and evaluation of an Exercise is Medicine™ on campus week

UNLABELLED Exercise is Medicine™ (EiM) on campus targets physical activity (PA) participation on college campuses. Limited research has addressed how PA initiatives can be operationalized on college campuses. PURPOSE To describe the implementation of EiM on a large U.S. university campus and present preliminary outcomes on participation and awareness. METHODS EiM week was implemented on a large university campus. Exercise stations were set-up at campus locations to encourage brief bouts of PA and educate about the benefits of PA. Evaluation included observations of participation, surveys, and intercept surveys to assess awareness and reach. RESULTS EiM week was implemented during Fall 2013. Exercise stations elicited 1771 exercise bouts from participants. Surveys indicated widespread reach across the university (13 of 17 colleges); most students (50.8%) became aware of the EiM campaign by passing by the exercise stations. Campus intercept surveys 1-week post-event indicated 54% students had heard about EiM, of which 39% had heard/seen the event through messages encouraging exercise. CONCLUSION The current study was successful in engaging a large, diverse population on a college campus. Lessons learned from the development, implementation, and evaluation of EiM on campus activities provide insight for university campuses looking to target student health and PA participation.