Normative values for the KOOS and WOMAC in a young athletic population: history of knee ligament injury is associated with lower scores

BACKGROUND

The use of patient-reported outcome measures to assess clinical outcomes after injury and surgery has become common in treating young athletes with orthopaedic injuries; however, normative data for these measures are limited and often include a wide range of ages and activity levels.

PURPOSE

To provide normative data for the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in a young and athletic population, and to compare scores between participants with a history of knee ligament injury and those with no history.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We administered the KOOS and WOMAC to 1177 college freshmen entering the United States Military Academy in June 2011. All participants were healthy and had been medically screened to meet the physical induction standards for military service. We calculated means, standard deviations, percentiles, ranges, and interquartile ranges for the KOOS and WOMAC by sex and injury history. We also compared median scale scores for those with a history of knee ligament injury with those with no history using the Kruskal-Wallis test.

RESULTS

Among the 1177 participants, 971 were male (age, 18.8 ± 0.9 years), and the remaining 206 were female (age, 18.7 ± 0.8 years). Normative median values and interquartile ranges (IQRs) for the KOOS scale scores among men with no history of knee ligament injury were the following: Symptoms (96.4; IQR, 10.7), Pain (100; IQR, 2.8), Functional Activities of Daily Living (ADL) (100; IQR, 0.0), Sports and Recreation Function (100; IQR, 5.0), and Knee-Related Quality of Life (QOL) (100; IQR, 12.5). For women with no history of knee ligament injury, the KOOS scale scores were the following: Symptoms (92.9; IQR, 14.3), Pain (100; IQR, 5.6), Functional ADL (100; IQR, 2.9), Sports and Recreation Function (100; IQR, 10.0), and Knee-Related QOL (93.8; IQR, 18.8). Among the men, 139 (14%) reported a history of knee ligament injury, while 33 (16%) women also reported a history of injury. All KOOS scale scores and the WOMAC Stiffness and Function scale scores were significantly lower (P < .05) for men who reported a history of knee ligament injury. Similarly, Symptoms, Pain, and Knee-Related QOL on the KOOS and Pain on the WOMAC were significantly lower among women with a history of knee ligament injury.

CONCLUSION

Normative values for all KOOS scales suggest a high level of functioning among participants with no history of knee ligament injury. Despite meeting the medical standards for military service, participants with a history of knee ligament injury had significantly lower KOOS and WOMAC scores upon entry to military service.

Simple method of glenoid bone loss calculation using ipsilateral magnetic resonance imaging

BACKGROUND

Current methods for estimating glenoid bone loss in patients with chronic shoulder instability include computed tomography imaging with 3-dimensional reconstruction, specialized computer software, and imaging of the contralateral shoulder. An ideal method of glenoid measurement would require only magnetic resonance imaging (MRI) of the injured shoulder.

PURPOSE

To determine whether MRI measurement of glenoid height, as well as sex, could be used to estimate glenoid width in healthy subjects with no history of shoulder instability.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Bilateral shoulder MRIs were obtained in a healthy cohort of young athletes as part of the baseline assessment in a prospective cohort study. A musculoskeletal radiologist measured glenoid height and width using the sagittal MRI cuts. Univariate and multivariate regression analyses were performed to determine whether demographic and MRI measurements of the glenoid could be used to estimate glenoid width.

RESULTS

Of the 1264 shoulder MRIs evaluated, the mean glenoid width was 26.67 mm (±2.49 mm), and the mean glenoid height was 42.15 mm (±3.00 mm). There were significant differences between the 129 female glenoids and the 1035 male glenoids for both width (23.1 mm, 27.1 mm, respectively, P < .0001) and height (37.9 mm, 42.7 mm, respectively, P < .0001); however, the relationship between glenoid height and width was similar for both men and women. The glenoid width was found to correlate with the height measurement (r = 0.56) for the entire cohort. Based on the results of linear regression analysis, controlling for the influence of sex, a formula was created that represents the relationship between these variables for male subjects: Glenoid Width = (1/3 Height) + 15 mm. Female patients are estimated with a formula that represents the same slope but a different intercept: W = 1/3 H + 13 mm.

CONCLUSION

Significant differences in glenoid height and width were found by sex; however, the relationship between height and width was similar. These variables are correlated, and the resultant formula can be used to estimate the expected glenoid width in a patient with bone loss. This formula allows for easy calculation of the amount of glenoid bone loss with only a ruler and an MRI of the injured shoulder.

Serum relaxin levels in young athletic men are comparable with those in women

Relaxin was originally described as a reproductive hormone that mediated joint laxity in pregnant women and has been minimally studied in men. The purpose of this descriptive laboratory and clinical study was to evaluate serum relaxin in a young, primarily male population and compare levels between the sexes. In addition, the authors evaluated the relationship between relaxin and generalized laxity.

Incidence and risk factors associated with meniscal injuries among active-duty US military service members

CONTEXT

Few population-based studies have examined the incidence of meniscal injuries, and limited information is available on the influence of patient's demographic and occupational factors.

OBJECTIVE

To examine the incidence of meniscal injuries and the influence of demographic and occupational factors among active-duty US service members between 1998 and 2006.

DESIGN

Cohort study.

SETTING

Using the International Classification of Diseases (9th revision) codes 836.0 (medial meniscus), 836.1 (lateral meniscus), and 836.2 (meniscus unspecified), we extracted injury data from the Defense Medical Surveillance System to identify all acute meniscal injuries among active-duty military personnel.

PATIENTS OR OTHER PARTICIPANTS

Active-duty military personnel serving in all branches of military service during the study period.

MAIN OUTCOME MEASURE(S)

Incidence rate (IR) per 1000 person-years at risk and crude and adjusted rates by strata for age, sex, race, rank, and service.

RESULTS

During the study period, 100201 acute meniscal injuries and 12115606 person-years at risk for injury were documented. The overall IR was 8.27 (95% confidence interval [CI] = 8.22, 8.32) per 1000 person-years. Main effects were noted for all demographic and occupational variables (P < .001), indicating that age, sex, race, rank, and service were associated with the incidence of meniscal injuries. Men were almost 20% more likely to experience an acute meniscal injury than were women (incidence rate ratio = 1.18, 95% CI = 1.15, 1.20). The rate of meniscal injury increased with age; those older than 40 years of age experienced injuries more than 4 times as often as those under 20 years of age (incidence rate ratio = 4.25, 95% CI=4.08,4.42).

CONCLUSIONS

The incidence of meniscal injury was substantially higher in this study than in previously reported studies. Male sex, increasing age, and service in the Army or Marine Corps were factors associated with meniscal injuries.

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

BACKGROUND

The 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.

RESULTS

Data 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.

CONCLUSIONS

These 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.

Epidemiology of acromioclavicular joint injury in young athletes

BACKGROUND

Acromioclavicular (AC) joint injuries, particularly sprains, are common in athletic populations and may result in significant time lost to injury. However, surprisingly, little is known of the epidemiology of this injury.

PURPOSE

To define the incidence of AC joint injuries and to determine the risk factors for injury.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

A longitudinal cohort study was performed to determine the incidence and characteristics of AC joint injury at the United States Military Academy between 2005 and 2009. All suspected AC joint injuries were reviewed by an independent orthopaedic surgeon using both chart reviews as well as assessments of radiological imaging studies. Injuries were graded according to the modified Rockwood classification system as well as dichotomized into low-grade (Rockwood types I and II) and high-grade (Rockwood types III, IV, V, and VI) injuries for analysis. Injury mechanisms, return-to-play timing, and athlete-exposures were documented and analyzed. χ(2) and Poisson regression analyses were performed, with statistical significance set at P < .05.

RESULTS

During the study period, 162 new AC joint injuries and 17,606 person-years at risk were documented, for an overall incidence rate of 9.2 per 1000 person-years. The majority of the AC joint injuries were low-grade (145 sprains, 89%) injuries, with 17 high-grade injuries. Overall, male patients experienced a significantly higher incidence rate for AC joint injuries than female patients (incidence rate ratio [IRR], 2.18; 95% confidence interval [CI], 1.21-4.31). An AC joint injury occurred most commonly during athletics (91%). The incidence rate of AC joint injury was significantly higher in intercollegiate athletes than intramural athletics when using athlete-exposure as a measure of person-time at risk (IRR, 2.11; 95% CI, 1.31-3.56). Similarly, the incidence rate of AC injury was significantly higher among male intercollegiate athletes when compared to female athletes (IRR, 3.56; 95% CI, 1.74-8.49) when using athlete-exposure as the denominator. The intercollegiate sports of men's rugby, wrestling, and hockey had the highest incidence rate of AC joint injury. Acromioclavicular injuries resulted in at least 1359 total days lost to injury and an average of 18.4 days lost per athlete. The average time lost to injury for low-grade sprains was 10.4 days compared with high-grade injuries at 63.7 days. Of the patients with high-grade injuries, 71% elected to undergo coracoclavicular/AC reconstructions. The rate of surgical intervention was 19 times higher for high-grade AC joint injuries than for low-grade injuries (IRR, 19.2; 95% CI, 7.64-48.23; P < .0001).

CONCLUSION

Acromioclavicular separations are relatively common in young athletes. Most injuries occur during contact sports such as rugby, wrestling, and hockey. Male athletes are at greater risk than female athletes. Intercollegiate athletes are at greater risk than intramural athletes. The average time lost to sport due to AC joint injury was 18 days, with low-grade injuries averaging 10 days lost. High-grade injuries averaged 64 days lost to sport, and 71% elected to undergo surgical repair/reconstruction.

Clavicle fractures in the United States military: incidence and characteristics

BACKGROUND

Although it is generally known that clavicle fractures represent a common injury of the shoulder girdle in the general population, the true incidence in the active duty military population is unknown. Given the implications for such injuries on the ability to perform occupation-specific tasks, determining the incidence in the U.S. military population is worthwhile. The purpose of this study was to determine the incidence of clavicle fractures in the U.S. military and to identify any demographic risk factors for injury.

METHODS

We performed a query of the Defense Medical Epidemiology Database with the code from the International Classification of Diseases, Ninth Revision, for clavicle fractures for the years 1999 through 2008. An overall injury incidence was calculated, in addition to multivariate analysis, to determine independent risk factors among the following demographic considerations: sex, race, branch of military service, rank, and age.

RESULTS

During the study period, a total of 12,514 clavicle fractures were documented among an at-risk population of 13,770,767 person-years for an incidence rate (IR) of 0.91 per 1,000 person-years in the U.S. Military. Males, when compared with females, were more than twice as likely to sustain a clavicle fracture (IR ratios [IRR], 2.30; 95% confidence intervals [CI], 2.12-2.49). The peak incidence of clavicle fractures occurred in the age groups of <20 and 20 to 24. Compared to black service members, the white service members were associated with significantly higher rate of clavicle fractures (IRR, 2.45; 95% CI, 2.28-2.63). The service members serving in the Marine Corps were associated with a higher IR of clavicle fractures when compared to those in the Navy (IRR, 1.44; 95% CI, 1.35-1.53). Junior enlisted service members were 34% as likely to sustain a clavicle fracture when compared to senior officers (IRR, 1.46; 95% CI, 1.34-1.60 and IRR, 1.12; 95% CI, 0.99-1.28, respectively).

CONCLUSIONS

The incidence of clavicle fractures among U.S. military personnel (0.908 per 1,000 person-years) is higher than previous epidemiological reports.

Survival comparison of allograft and autograft anterior cruciate ligament reconstruction at the United States Military Academy

BACKGROUND

There is recent evidence that use of allograft tendons for anterior cruciate ligament (ACL) reconstruction in young patients may result in increased failure rates compared with autologous grafts.

HYPOTHESIS

Allograft ACL reconstruction will result in higher failure rates in young athletes compared with autograft reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective cohort study of cadets at the United States Military Academy (USMA) was performed to assess performance of ACL reconstructions performed before entrance to service. Members of the classes of 2007 through 2013 who had undergone prior ACL reconstruction were identified through the Department of Defense Medical Evaluation Review Board reporting and waiver process and evaluated on the first day of matriculation. These participants were followed during their tenure at the academy with revision ACL reconstruction as the primary outcome measure of interest. Kaplan-Meier survival analysis was performed for all graft types using STATA with significance set as P < .05.

RESULTS

A total of 120 cadets underwent 122 ACL reconstructions (2 bilateral) before matriculation and compose the prospective cohort. This cohort included 30 female and 90 male cadets. Of these 122 knees with prior ACL reconstructions, the grafts used were 61 bone-patellar tendon-bone (BTB), 45 hamstring, and 16 allograft. A total of 20 failures occurred among this cohort at an average of 545 days from matriculation. Of the failures requiring revision, 7 were BTB (11% of all BTB), 7 were allograft (44% of all allograft), and 6 were hamstring (13% of all hamstring). There was no significant difference in the graft failure between the BTB and hamstring autograft groups. In contrast, those who entered the USMA with an allograft were 7.7 times more likely to experience a subsequent graft failure during the follow-up period when compared with the BTB autograft group (hazard ratio = 7.74; 95% confidence interval [CI], 2.67-22.38; P < .001). When allografts were compared with all autografts combined, a similar increase failure was noted in the allograft group (hazard ratio = 6.71; 95% CI, 2.64-17.06; P < .001).

CONCLUSION

In this young active cohort, individuals having undergone an allograft ACL reconstruction were significantly more likely to experience clinical failure requiring revision reconstruction compared with those who underwent autologous graft reconstruction. The authors recommend the use of autograft in ACL reconstruction in young athletes.

Epidemiology of meniscal injury associated with ACL tears in young athletes

The epidemiologic characteristics of concomitant meniscal tears that occur at the time of anterior cruciate ligament (ACL) injury have been variably reported. The purpose of this study was to assess the epidemiology of meniscal tears that occur in the ACL-injured knee of a young, athletic population at a single institution. We were unable to find a difference in meniscal tear incidence based on sex, mechanism of injury, sport, or time to surgery. In addition, we found that the cumulative incidence of isolated medial meniscal tears was significantly higher than the cumulative incidence of isolated lateral meniscal tears. Our prospective study design and ability to identify and follow all patients in our study population make this a unique study.

Arthroscopic basic task performance in shoulder simulator model correlates with similar task performance in cadavers

BACKGROUND

Attainment of the technical skill necessary to safely perform arthroscopic procedures requires the instruction of orthopaedic surgery residents in basic arthroscopic skills. Although previous studies involving shoulder arthroscopy simulators have demonstrated a correlation between task performance and the level of prior arthroscopic experience, data demonstrating the correlation of simulator performance with arthroscopic skill in a surgical setting are scarce. Our goal was to evaluate the correlation between timed task performance in an arthroscopic shoulder simulator and timed task performance in a cadaveric shoulder arthroscopy model.

METHODS

Subjects were recruited from among residents and attending surgeons in an orthopaedic surgery residency program. Each subject was tested on an arthroscopic shoulder simulator and objectively scored on the basis of the time taken to complete a standardized object selection program. After an interval of at least two weeks, each subject was then tested on a cadaveric shoulder arthroscopy model designed to replicate the shoulder arthroscopy simulator testing protocol, and the time to completion was again recorded. Both testing protocols involved the simple task of placing a probe on a series of assigned locations in the glenohumeral joint. Spearman rank correlation analysis was performed, and regression analysis was used to determine the predictive ability of the simulator score.

RESULTS

The performance time on the simulation program was strongly correlated with the performance time on the cadaveric model (r = 0.736, p < 0.001). The time required to complete the simulator task was a significant predictor of the time required to complete the cadaveric task (t = 4.48, p < 0.001).

CONCLUSIONS

These results demonstrated a strong correlation between performance of basic arthroscopic tasks in a simulator model and performance of the same tasks in a cadaveric model.

Epidemiology of Major League Baseball injuries

BACKGROUND

Little is known about the injury rates in Major League Baseball (MLB) players, as a formal injury surveillance system does not exist. The goal of this study was to characterize the epidemiology of MLB injuries over a 7-year period.

HYPOTHESIS

Injuries in MLB would be common.

STUDY DESIGN

Descriptive epidemiologic study.

METHODS

The authors analyzed the MLB disabled list data from 2002 through 2008. Injuries were analyzed for differences between seasons, as well as during seasons on a monthly basis. The injuries were categorized by major anatomic zones and then further stratified based on injury type. Position-specific subanalyses for pitcher and position players were performed.

RESULTS

From the 2002 season through the 2008 season, an average of 438.9 players per year were placed on the disabled list, for a rate of 3.61 per 1000 athlete-exposures. There was a significant 37% increase in injuries between 2005 and 2008. The highest injury rate during the season was during the month of April (5.73/1000 exposures) and the lowest in September (0.54/1000 exposures). No differences were noted in the injury rates between the National League and the American League (incidence rate ratio [IRR] = 1.06; 95% confidence interval [CI] = 0.98, 1.15). Pitchers experienced 34% higher incidence rates for injury compared with fielders during the study period (IRR = 1.34; 95% CI = 1.25, 1.44). Among all player injuries, upper extremity injuries accounted for 51.4% while lower extremity injuries accounted for 30.6%. Injuries to the spine and core musculature accounted for 11.7% while other injuries and illnesses were 6.3% of the total disabled list entries. There was a significant association between position played and anatomic region injured (P < .001), with pitchers experiencing a significantly greater proportion of injuries to the upper extremity (67.0%; 95% CI = 63.1%, 70.9%) compared with fielders (32.1%; 95% CI = 29.1%, 35.1%). Conversely, fielders experienced a significantly greater proportion of injuries to the lower extremity (47.5%; 95% CI = 43.8%, 51.1%) compared with pitchers (16.9%; 95% CI = 14.9%, 18.8%). The mean number of days on the disabled list was 56.6. Overall, a greater proportion of disability days were experienced by pitchers (62.4%; 95% CI = 62.0%, 62.8%; P < .001) compared with fielders (37.6%; 95% CI = 37.3%, 37.9%).

CONCLUSION

Injuries in MLB resulting in disabled list designation are common. Upper extremity injuries were predominant in pitchers, while lower extremity injuries are more common in position players. These data may be used in the development of a formal MLB injury database, as well as in the development and implementation of specific preseason training and in-season conditioning for injury prevention.

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).

Treatment of meniscal injuries in young athletes

The young, active patient with a meniscal tear poses a significant challenge for the surgeon. Multiple factors influence the treatment of meniscal pathology and the ultimate goal of meniscal surgery should be to remove only torn and nonfunctional tissue by limited meniscectomy or to repair amenable tears. The chondroprotective significance of the meniscus has influenced the current treatment of meniscal injuries in young athletes with the emphasis on repairing meniscus tears to include complex tears and tears in the avascular zone. Partial meniscectomy and meniscal repair techniques have provided good long-term clinical success and return to activity. The decision to debride versus repair a meniscus depends on tear pattern, location, and the patient's willingness to comply with postoperative restrictions. In patients with symptomatic meniscus deficiency, meniscal allograft transplant is an option that may provide pain relief but may not allow return to sports. The purpose of this article is to provide a succinct review of the diagnostic and management principles for the young, active patient with a meniscal tear.

Risk factors for syndesmotic and medial ankle sprain: role of sex, sport, and level of competition

BACKGROUND

Syndesmotic and medial ankle sprains constitute up to 15% of all ankle sprains in athletic populations and can result in significant time lost to injury and long-term disability.

PURPOSE

The objective of this study was to estimate the rate of syndesmotic and medial ankle sprain injuries and identify risk factors associated with these injuries within the physically active cadet population at the United States Military Academy (USMA).

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The Cadet Illness and Injury Tracking System (CIITS) database at USMA was queried for all ankle injuries between 2005 and 2009. Sex, level of competition, and exposure to sport were among risk factors analyzed.

RESULTS

Among 20 336 person-years, 1206 cadets sustained ankle sprain. Syndesmotic (6.7%) and medial (5.1%) ankle sprains had an incidence rate (IR) of 4.8 and 3.5 per 1000 person-years, respectively. Compared with women, men were 3 times more likely to experience medial ankle sprain (IR ratio [IRR] 3.37; 95% confidence interval [CI]: 1.05, 10.74], but there was no difference in rate of syndesmotic sprains by sex (IRR 1.06; 95% CI: 0.58, 1.95). Athletics accounted for 81% of syndesmotic sprains and 64% of medial sprains. Sprint football (52.3), team handball (men's, 34.7), soccer (men's, 30.5; women's, 6.5), and basketball (men's, 24.8; women's, 6.7) had the highest syndesmotic IR per 100 000 athlete-exposures. Medial sprain IR was highest in men's rugby (16.6) and gymnastics (14.0). When analyzed by athlete-exposure, male intercollegiate athletes had a greater risk of syndesmotic sprain than their female counterparts (3.53; 95% CI: 1.26, 9.83). Furthermore, intercollegiate level of competition had an increased risk of syndesmotic sprain when compared with intramural level (IRR 2.41; 95% CI: 1.03, 5.65).

CONCLUSION

Male athletes have an over threefold greater risk of medial ankle sprain. Male sex and higher level of competition are risk factors for syndesmotic ankle sprain during athletics.

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.

Incidence of ankle sprains among active-duty members of the United States Armed Services from 1998 through 2006

CONTEXT

Ankle sprains have been reported as one of the most common injuries sustained by members of the US Armed Services. However, little is known about the incidence rate and injury patterns associated with ankle sprains in this population.

OBJECTIVE

To examine the incidence of ankle sprains among active-duty members of the US Armed Services from 1998 through 2006. A secondary objective was to describe the sex, age, and service-specific injury patterns in this young, physically active population.

DESIGN

Cohort study.

PATIENTS OR OTHER PARTICIPANTS

All active-duty service members from the day they enter military service until the day they leave military service and US Army Reserve and National Guard service members during periods of active duty and mobilization.

MAIN OUTCOME MEASURE(S)

Injury data were extracted from the Defense Medical Epidemiological Database from 1998 through 2006. All data for ankle sprains, coded according to the International Classification of Diseases (9th revision), were included. Cases were limited to those injuries reported as first occurrences. Incidence rates (IRs) were calculated per 1000 person-years by sex, age, and service. Incidence rate ratios (IRRs) and 95% confidence intervals (95% CIs) were used to assess the strength of association between the incidence of ankle sprain and the independent variables of sex, age, and service.

RESULTS

From 1998 through 2006, 423 581 service members sustained ankle sprains and 12 118 863 person-years at risk to injury were documented in this population. The incidence rate was 34.95 (95% CI = 34.85, 35.06) per 1000 person-years at risk. Females were 21% more likely (IRR = 1.21, 95% CI = 1.21, 1.23) to sustain an ankle sprain than males. Sex-specific IR varied by age and service. Differences in the rate of ankle sprains were also noted by age and service.

CONCLUSIONS

The incidence of ankle sprains among US service members was 5 times greater than that previously reported in civilian population studies. Sex, age, and branch of military service are important factors related to the incidence of ankle sprains in this population.

Incidence of acute traumatic patellar dislocation among active-duty United States military service members

BACKGROUND

Although some studies have reported an increased incidence of patellar dislocations within active populations, few studies have reported incidence rates and examined risk factors for this injury.

PURPOSE

To examine the incidence of patellar dislocation injuries and the influence of demographic and occupational risk factors associated with injury among active-duty United States (US) service members between 1998 and 2007.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Using the Defense Medical Surveillance System, a search was performed for International Classification of Disease, 9th Revision (ICD-9) code 836.3 among all US service members on active duty during the study period. Multivariable Poisson regression analysis was used to estimate the rate of patellar dislocation per 1000 person-years at risk to injury. Incidence rates (IRs) and incidence rate ratios (IRRs) for patellar dislocation along with 95% confidence intervals (CIs) were estimated by gender, age, race, branch of military service, and rank while controlling for the other variables in the model.

RESULTS

There were a total of 9299 individuals with documented patellar dislocation injuries among a population at risk of 13 443 448 person-years. The IR was 0.69 per 1000 person-years at risk. Women were 61% more likely (IRR, 1.61; 95% CI, 1.53-1.69) to sustain a patellar dislocation injury than men. Rates were highest in the youngest age group and decreased with increasing age. Service members aged <20 years were 84% more likely (IRR, 1.84; 95% CI, 1.61-2.10) to sustain a patellar dislocation injury as service members aged ≥40 years. Differences were also noted by race, service, and rank.

CONCLUSION

The incidence of patellar dislocation injuries among US service members was an order of magnitude greater than that previously reported in civilian population studies. Gender, age, race, rank, and branch of military service are important risk factors related to the incidence of patellar dislocation injuries in this population.

Associations between three clinical assessment tools for postural stability

STUDY DESIGN

Clinical Measurement, Correlation, Reliability

OBJECTIVES

To assess the relationship between the Single Leg Balance (SLB), modified Balance Error Scoring System (mBESS), and modified Star Excursion Balance (mSEBT) tests and secondarily to assess inter-rater and test-retest reliability of these tests.

BACKGROUND

Ankle sprains often result in chronic instability and dysfunction. Several clinical tests assess postural deficits as a potential cause of this dysfunction; however, limited information exists pertaining to the relationship that these tests have with one another.

METHODS

Two independent examiners measured the performance of 34 healthy participants completing the SLB Test, mBESS test, and mSEBT at two different time periods. The relationship between tests was assessed using the Pearson Correlation and Fisher's Exact Tests. Inter-rater and test-retest reliability were assessed using the intraclass correlation coefficient (ICC) and Kappa statistics.

RESULTS

A significant correlation (r = -0.35) was observed between the mSEBT and the mBESS. Fisher's Exact Test showed a significant association between the SLB Test and mBESS (P = .048), but no association between the SLB and mSEBT (P = 1.000). Inter-rater reliability was excellent for the mSEBT and fair for the mBESS (ICCs of .91 and .61 respectively). Excellent agreement was observed between raters for the SLB test (k = 1.00). Test-retest reliability was excellent for the mSEBT (ICC = 0.98) and fair for the mBESS (ICC = 0.74). There was poor test-retest agreement for the SLB test (k = .211).

CONCLUSION

THERE WAS A SIGNIFICANT RELATIONSHIP OBSERVED BETWEEN THE SLB TEST, MBESS TEST, AND MSEBT: however; strength of association measures showed limited overlap between these tests. This suggests that these tests are interrelated but may not assess equal components of postural stability.

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.

Epidemiology of ankle sprain at the United States Military Academy

BACKGROUND

Ankle sprain is a common injury in athletic populations that results in significant time lost to injury.

HYPOTHESIS

The incidence rates (IRs) of ankle ligament sprains are influenced by gender, height, weight, body mass index (BMI), physical conditioning, level of competition, type of sport, and athlete exposure to sport.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A longitudinal cohort study was performed to determine the effect of risk factors for ankle sprain at the United States Military Academy between 2005 and 2007.

RESULTS

A total 614 cadets sustained new ankle sprains during 10 511 person-years at risk, resulting in an overall IR of 58.4 per 1000 person-years. Women (96.4), compared with men (52.7), had a significantly increased rate ratio (IRR) for ankle sprain of 1.83 (95% confidence interval [CI], 1.52-2.20). Men with ankle sprains had higher mean height, weight, and BMI than uninjured men (P <.001). Men with ankle sprains had higher average scores in push-ups, sit-ups, and run time than uninjured men (P <.001). Ankle sprain occurred most commonly during athletics (64.1%). Ankle sprain IR did not significantly differ between intercollegiate and intramural athletic competition after controlling for athlete-exposure (IRR, 1.05; 95% CI, 0.81-1.37). The ankle sprain IRR of female compared with male intercollegiate athletes was 0.93 (95% CI, 0.67-1.32) per 1000 person-years and 1.04 (95% CI, 0.74-1.47) per 1000 athlete-exposures. The intercollegiate sports of men's rugby, women's cheerleading, and men's/women's basketball, soccer, and lacrosse had the highest ankle sprain IR.

CONCLUSION

Higher mean height and weight in men, increased BMI in men, greater physical conditioning in men, and athlete exposure to selected sports were all risk factors for ankle sprain.