Sally B. Mountcastle

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.

Incidence of Glenohumeral Instability in Collegiate Athletics

Background Glenohumeral instability is a common injury sustained by young athletes. Surprisingly, little is known regarding the incidence of glenohumeral instability in collegiate athletes or the relevant risk factors for injury. A better understanding of the populations most at risk may be used to develop preventive strategies. Hypothesis The incidence of glenohumeral instability in collegiate athletics is high, and it is affected by sex, sport, type of event, and mechanism of injury. Study Design Descriptive epidemiologic study. Methods The National Collegiate Athletic Association injury database was queried for all glenohumeral instability events occurring between the years 1989 and 2004. An analysis of the injuries was performed by sport, activity (competition versus practice), sex, type of event (primary versus recurrent), mechanism of injury, and time loss from athletic performance. Incidence rates and incidence rate ratios were calculated. Results A total of 4080 glenohumeral instability events were documented for an incidence rate of 0.12 injuries per 1000 athlete exposures. The sport with the greatest injury rate was mens spring football, with 0.40 injuries per 1000 athlete exposures. Overall, athletes sustained more glenohumeral instability events during games than practices (incidence rate ratio [IRR], 3.50; 95% confidence interval [CI], 3.29-3.73). Male athletes sustained more injuries than did female athletes (IRR, 2.67; 95% CI, 2.43-2.93). Female athletes were more likely to sustain an instability event as the result of contact with an object (IRR, 2.43; 95% CI, 2.08-2.84), whereas male athletes were more likely to sustain an event from player contact (IRR, 2.74; 95% CI, 2.31-3.25). Time lost to sport (>10 days) occurred in 45% of glenohumeral instability events. Conclusion Glenohumeral instability is a relatively common injury sustained by collegiate athletes. More injuries occurred during competition and among male athletes.

Gender Differences in Anterior Cruciate Ligament Injury Vary With Activity Epidemiology of Anterior Cruciate Ligament Injuries in a Young, Athletic Population

Background Previous studies have shown that women involved in similar activities as men are at increased risk for anterior cruciate ligament injuries. Hypothesis The incidence rate of complete anterior cruciate ligament tears for men and women in our athletic, college-aged population is similar. Study Design Descriptive epidemiology study. Methods Students graduating in class years 1994 to 2003 at our institution who sustained complete anterior cruciate ligament tears were assessed for mechanism of injury and type of sport played at time of injury. We calculated the incidence proportion, an estimation of risk, by gender and class year, and the incidence proportion ratio comparing men and women by class year. We also calculated incidence rates by gender and type of sport played and incidence rate ratios comparing men and women. Results There were 353 anterior cruciate ligament injuries in the 10 classes studied. We found an overall, 4-year incidence proportion of 3.24 per 100 (95% confidence interval, 2.89-3.63) for men and 3.51 (95% confidence interval, 2.65-4.65) for women (incidence proportion ratio, 1.09 [95% confidence interval, 0.80-1.47]). The overall anterior cruciate ligament injury rate, excluding male-only sports, was significantly greater in women (incidence rate ratio, 1.51 [95% confidence interval, 1.03-2.21]). We found significantly greater injury rates among women in a gymnastics course (incidence rate ratio, 5.67 [95% confidence interval, 1.99-16.16]), indoor obstacle course test (incidence rate ratio, 3.72 [95% confidence interval, 1.25-11.10]), and basketball (incidence rate ratio, 2.42 [95% confidence interval, 1.05-5.59]). Conclusion We found little gender difference in the overall risk of an anterior cruciate ligament tear; however, there were gender differences in injury rates when specific sports and activities were compared and when male-only sports were removed from the overall rate assessment.

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.

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.

The incidence of plantar fasciitis in the United States military.

BACKGROUND Although plantar fasciitis is the most common cause of heel pain, little has been reported on the incidence rates of this disorder. We sought to determine the incidence rate and demographic risk factors of plantar fasciitis in an ethnically diverse and physically active population of United States military service members. METHODS A query was performed with use of the Defense Medical Epidemiology Database for the International Classification of Diseases, Ninth Revision, Clinical Modification, code for plantar fasciitis (728.71). Multivariate Poisson regression analysis was used to estimate the rate of plantar fasciitis per 1000 person-years, while controlling for sex, race, rank, service, and age. RESULTS The overall unadjusted incidence rate of plantar fasciitis was 10.5 per 1000 person-years. Compared with men, women had a significantly increased adjusted incidence rate ratio for plantar fasciitis of 1.96 (95% confidence interval, 1.94 to 1.99). The adjusted incidence rate ratio for black service members compared with white service members was 1.12 (95% confidence interval, 1.09 to 1.12). With junior officers as the referent category, junior enlisted, senior enlisted, and senior officer rank groups had a significantly increased adjusted incidence rate ratio for plantar fasciitis: 1.20 (95% confidence interval, 1.18 to 1.23), 1.19 (95% confidence interval, 1.17 to 1.22), and 1.56 (95% confidence interval, 1.52 to 1.61), respectively. Compared with service members in the Air Force, those in the Army and Marines had a significantly increased adjusted incidence rate ratio for plantar fasciitis of 1.85 (95% confidence interval, 1.82 to 1.87) and 1.28 (95% confidence interval, 1.25 to 1.30), respectively. The adjusted incidence rate ratio for the age group of forty years old or more compared with the twenty to twenty-four-year-old group was 3.42 (95% confidence interval, 3.34 to 3.51). CONCLUSIONS Female sex; black race; junior enlisted, senior enlisted, and senior officer rank groups; service in the Army or Marines; and increasing age are all risk factors for plantar fasciitis.

Incidence of Anterior Cruciate Ligament Injury among Active Duty U.S. Military Servicemen and Servicewomen

Although some studies have reported an increased incidence of anterior cruciate ligament (ACL) injuries in women athletes, little is known about the gender differences in injury patterns in the U.S. military. Using the Defense Medical Epidemiology Database, a search was performed for International Classification of Diseases, 9th Revision (ICD-9) codes 717.83 (old disruption of ACL) and 844.2 (sprain, strain cruciate ligament of the knee) among all servicemen and servicewomen between 1997 and 2003. Multivariate Poisson regression analysis was used to estimate the rate of ACL injuries per 1000 person-years, controlling for age and race, for each ICD-9 code. We computed rate ratios and 95% confidence intervals (CIs) by using male as the reference category. The injury rates for code 717.83 were 3.09 cases per 1,000 person-years for men and 2.29 cases per 1000 person-years for women, controlling for age and race (relative risk, 0.74; 95% CI, 0.71-0.76). The injury rates for ICD-9 code 844.2 were 3.79 cases per 1000 person-years for men and 2.95 cases per 1,000 person-years for women, controlling for age and race (relative risk, 0.78; 95% CI, 0.76-0.80). There was not an observed increase in the incidence of ACL injuries among female soldiers in the U.S. military between 1997 and 2003.

Incidence of Major Tendon Ruptures and Anterior Cruciate Ligament Tears in US Army Soldiers

Background Although a rare event, the prevalence of major tendon rupture has increased in recent decades. Identification of risk factors is important for prevention purposes. Hypothesis Race is a risk factor for major tendon ruptures. Study Design Cohort study (prevalence); Level of evidence, 2. Methods All patients admitted for surgical management of a rupture of a major tendon at Womack Army Medical Center, Fort Bragg, North Carolina, in 1995 and 1996 were identified and evaluated for risk factors. Results The authors identified 52 major tendon ruptures 29 Achilles, 12 patellar, 7 pectoralis major, and 4 quadriceps tendon ruptures. All patients were active-duty soldiers, and 1 was a female soldier. Forty-one tendon ruptures occurred among black soldiers, 8 occurred among white soldiers, and 3 occurred among Latino soldiers. The population at risk included 93 224 exposures during the 2-year period, of which 67.1% were white, 24.5% were black, and 8.4% were self-classified as other race. The rate ratio for tendon rupture, adjusted for gender and age, was 13.3 (95% confidence interval, 6.2-28.5) between blacks and whites and 2.9 (95% confidence interval, 0.8-10.9) between Latinos and whites. Conclusion The rate of major tendon rupture was 13 times greater for black men in this study population when compared with whites. Interventions among those at a higher risk for injury should be considered.

The incidence of scaphoid fracture in a military population

BACKGROUND The rate of occurrence of scaphoid injury is not well known. The incidence of scaphoid fracture has been described mostly in small, injured cohort populations, which may underestimate its frequency. We studied the epidemiology of the scaphoid fracture using a large database in a military population. PATIENTS AND METHODS The Defense Medical Epidemiology Database (DMED), a comprehensive database which tracks medical care for all four military services of the United States, was queried for the first occurrence of scaphoid fractures using International Classification of Diseases (ICD)-9 code 814.01. Data were evaluated using multivariate Poisson analysis, controlling for co-variate factors. RESULTS We noted 14,704 scaphoid fractures in a population at a risk of 12,117,749 person-years. The unadjusted incidence of scaphoid fracture was 1.21/1000 person-years. Males were significantly more likely to sustain scaphoid fractures, with an adjusted rate ratio (RR) of 1.55 (95% confidence interval (C.I.), 1.47, 1.64), compared to females. The 20-24-year-old age group had the highest incidence of scaphoid fracture at 1.64/1000 person-years, and showed a significantly higher RR compared to the population aged greater than 40 years (adjusted RR 1.55, 95% C.I., 1.38, 1.66). Whites sustained scaphoid fractures at a significantly higher rate than African Americans (adjusted RR 1.32, C.I., 1.26, 1.38). DISCUSSION/CONCLUSIONS When compared to the previous data on scaphoid fractures, our study showed a greater incidence of scaphoid fracture at 1.21/1000 person-years in the US military population. These data are derived from a large database which effectively captures the population at risk. Males, the younger age group and the white race were associated with higher rates of scaphoid injury in this specialised military population.

The Incidence of Primary Hip Osteoarthritis in Active Duty US Military Servicemembers

OBJECTIVE Although multiple studies have reported the prevalence of primary hip osteoarthritis (OA), little has been reported on incidence rates of hip OA. We sought to determine the incidence rate and demographic risk factors of hip OA in an ethnically diverse and physically active population of US military servicemembers. METHODS A query was performed using the US Defense Medical Epidemiology Database for the International Classification of Diseases, Ninth Revision, Clinical Modification code for hip OA (715.95). Multivariate Poisson regression analysis was used to estimate the rate of hip OA per 100,000 person-years, controlling for sex, race, age, rank, and service. RESULTS The overall unadjusted incidence rate of hip OA was 35 per 100,000 person-years. Women, compared with men, had a significantly increased adjusted incidence rate ratio for hip OA of 1.87 (95% confidence interval [95% CI] 1.73-2.01). The adjusted incidence rate ratio for black servicemembers when compared with white servicemembers was 1.32 (95% CI 1.23-1.41). The adjusted incidence rate ratio for the > or =40-year-old age group compared with the 20-year-old group was 22.21 (95% CI 17.54-28.14). With junior officers as the referent category, junior enlisted, senior enlisted, and senior officers rank groups had a significantly increased adjusted incidence rate ratio for hip OA. With the Air Force as the referent category, each service had a significantly increased adjusted incidence rate ratio for hip OA. CONCLUSION Female sex; black race; age > or =40 years; junior enlisted, senior enlisted, and senior officer rank groups; and military service in the Navy, Army, or Marines were all risk factors for hip OA.