Andrew E. Lincoln

Fractures of the Femoral Shaft in Children. Incidence, Mechanisms, and Sociodemographic Risk Factors*

BACKGROUND Fractures of the femoral shaft in children are caused by major musculoskeletal trauma and result in high direct and indirect medical costs. To date, the American literature has focused on treatment options and outcomes, but the epidemiology of these injuries has been generalized from Scandinavian studies reported in the 1970s and early 1980s. The goals of the current study were (1) to determine the age, gender, and race-specific rates and mechanisms of fractures of the femoral shaft in children in a large United-States-based population and (2) to identify associations between the rates of these fractures and multiple sociodemographic indicators. Such information is vital for preventive efforts. METHODS The Hospital Discharge Database of the Maryland Health Services Cost Review Commission for the years 1990 through 1996 was used to obtain demographic data on 1485 cases of acute fracture of the femoral shaft in patients who were less than eighteen years old, and data from the United States Bureau of the Census for the state of Maryland for the year 1990 were used to obtain denominator data. Reliable external-cause data were available from the 1995 and 1996 databases for 472 patients. Small-area analysis was performed at the zip-code level to determine associations between numerous sociodemographic indicators and the rate of femoral shaft fracture. RESULTS The annual rate of femoral shaft fracture in children was 19.15 per 100,000. With regard to age, there was a bimodal distribution, with peaks at two and seventeen years. Boys had higher rates of fracture than did girls at all ages, and blacks had higher rates than did whites. The primary mechanisms of fracture were age-dependent and included falls, for children less than six years old; motor vehicle-pedestrian accidents, for those six to nine years old; and motor-vehicle accidents, for teenagers. Firearm-related injuries accounted for 15 percent of the fractures among black adolescents. Adverse socioeconomic conditions were significantly associated with higher rates of fracture. CONCLUSIONS The rates and mechanisms of femoral shaft fractures in children depend on age, gender, and race. For children living in the United States today, the epidemiology of these fractures is different than that described in earlier, Scandinavian reports.

The Effect of Anterior Cruciate Ligament Reconstruction on the Risk of Knee Reinjury

Background Although there is evidence that very active, young patients are better served with anterior cruciate ligament reconstruction, there is a lack of objective data demonstrating that future knee injury is prevented by these procedures. Hypothesis Anterior cruciate ligament reconstruction protects against reinjury of the knee that would require reoperation. Study Design Retrospective cohort study. Methods A cohort of 6576 active-duty army personnel who had been hospitalized for anterior cruciate ligament injury from 1990 to 1996 were identified. Using the Total Army Injury and Health Outcomes Database, the authors followed these individuals for up to 9 years and collected clinical, demographic, and occupational data. These data were evaluated with bivariate and multivariable analyses to determine the effect of anterior cruciate ligament reconstruction on the rate of knee reinjury that required operation. Results Of the 6576 study subjects, 3795 subjects (58%) underwent anterior cruciate ligament reconstruction and 2781 (42%) did not. The rate of reoperation was significantly lower among the anterior cruciate ligament reconstruction group (4.90/100 person-years) compared with those treated conservatively (13.86/100 person-years; P < .0001). Proportional hazard regression analyses adjusted for age, race, sex, marital status, education, and physical activity level confirmed that anterior cruciate ligament reconstruction was protective against meniscal and cartilage reinjury (P < .0001). Secondary medial meniscal injury was more common than secondary lateral meniscal injury (P < .003). Younger age was the strongest predictor of failure of conservative management leading to late anterior cruciate ligament reconstruction (P < .0001). Conclusions Anterior cruciate ligament reconstruction protected against reoperation in this young, active population; younger subjects were more likely to require late anterior cruciate ligament reconstruction. Clinical Relevance Strong consideration should be given to anterior cruciate ligament reconstruction after anterior cruciate ligament injury in young, active individuals.

Epidemiology of Lacrosse Injuries in High School-Aged Girls and Boys: A 3-Year Prospective Study

Objective To report the types, mechanisms, and circumstances of lacrosse injuries incurred by high school-aged girls and boys during organized interscholastic and summer camp games. Study Design Descriptive epidemiology study. Methods For 3 years, the authors gathered data on girls’ and boys’ lacrosse injuries for 359 040 high school and 28 318 summer camp athletic exposures using a lacrosse-specific computerized injury surveillance system. The most prevalent injuries were organized into multifactorial injury scenarios. Results In high school play, the injury rate for adolescent boys (2.89 per 1000 athletic exposures) was slightly higher than that for girls (2.54 per 1000 athletic exposures) (incidence rate ratio = 1.14; 95% confidence interval, 1.00-1.30). The most prevalent injuries for adolescent girls and boys were knee and ankle sprains resulting from noncontact mechanisms. Male players had significantly higher rates of shoulder, neck, trunk, and back injuries and higher game-to-practice injury ratios. In addition, they had higher rates of concussive events from player-to-player contact. Female players had higher rates of overall head injuries, many involving contusions and abrasions from stick and ball contact. Conclusions The overall injury rates for boys’ and girls’ high school lacrosse were significantly lower than those for collegiate play. Significant differences existed between adolescent boys and girls with respect to injury mechanisms, body parts injured, and player and team activity at the time of injury.

Computer keyboard force and upper extremity symptoms

This case-control study assessed whether office workers who report more severe levels of musculoskeletal symptoms of the upper extremities demonstrate higher levels of keyforce in comparison to controls with less severe symptoms. Office workers reporting working on computer keyboards for four hours per day were classified as cases or controls based upon a median split on a Composite Symptom Severity score (cases = 23, controls = 25). Keyboard force and keying rate were measured during a 15-minute keyboarding task. Measures of task-related discomfort, muscular fatigue, pain, upper extremity symptoms, psychological distress and force were collected at baseline, post-keyboard task, and recovery. Ratings of perceived effort and task credibility were also obtained. Measures of work demands, perceived job stress, and upper extremity strength and flexibility were also collected. The results indicated group equivalence on reported work demands and upper extremity strength. Cases were more likely to receive a medical diagnosis of upper extremity cumulative trauma disorder, awaken from sleep due to symptoms, report higher levels of pain during work, experience greater impact of pain on function, and report higher workload pressure and lower support. Cases generated significantly higher keyboarding forces than controls, although both groups produced forces well above that required to operate the keyboard (4-5 times activation force). Cases reported higher levels of upper extremity symptoms and discomfort than controls, and these measures were highest after the keyboarding task for both groups. No significant correlation between keyforce and key rate was observed in either group. Results suggest that generation of excessive force while working on a computer keyboard may contribute to the severity of upper extremity symptoms. Clinically, the findings suggest that evaluating how an individual worker performs keyboarding tasks, or his or her workstyle, may be helpful in the management of these symptoms and disorders.

Sports and physical training injury hospitalizations in the army.

INTRODUCTION Injuries are the leading health problem in the military services. Sports and physical training activities are an area in which a substantial number of injuries can occur. Although athletic injuries are not often investigated in military populations, the Armed Forces database provides a unique opportunity to investigate sports injuries. METHODS An Army database of all hospital admissions for active duty Army personnel in the 1989-1994 period was used to study injuries resulting from sports and Army physical training. RESULTS For the 6-year time period reviewed, there were 13,861 hospital admissions for injuries resulting from sports or Army physical training: 94% (13,020) of these admissions were men and 6% (841) were women. The rates of sports injuries were 38 and 18 per 10,000 person-years for men and women, respectively. Sports injuries accounted for an average of 29,435 lost duty days each year: Men lost an average of 13 days per injury and women lost an average of 11 days per injury. Acute musculoskeletal injuries in the categories of fractures, sprains/strains, and dislocations accounted for 82% of all injuries. The knee was the most often injured body area in both genders, with the anterior cruciate ligament (ACL) identified as the most frequently injured body part overall. The top seven injuries were virtually identical for men and women, with only slight variations in order. Although the rates of all hospitalized sports injuries were higher for men than women, women had a higher proportion of ACL injuries from basketball and softball, ankle fractures from softball and head injuries from basketball. For men, football and basketball contributed to the highest rates of injuries. The highest injury rates for women were from Army physical training and basketball. For both men and women, Army physical training was the leading cause of lumbosacral strains. CONCLUSIONS Sports and Army physical training injuries account for a significant amount of lost duty time and impact military readiness.

Interventions for the primary prevention of work-related carpal tunnel syndrome

OBJECTIVE To evaluate interventions for the primary prevention of work-related carpal tunnel syndrome (CTS). SELECTION CRITERIA Studies had to include an engineering, administrative, personal, or multiple component intervention applied to a working or working-age population. All study designs that included comparison data were considered. Outcome measures included the incidence, symptoms, or risk factors for CTS, or a work-related musculoskeletal disorder of the upper extremity that included CTS in the definition. RESULTS Twenty-four studies met our inclusion criteria. Engineering interventions included alternative keyboards, computer mouse designs and wrist supports, keyboard support systems, and tool redesign. Personal interventions included ergonomics training, splint wearing, electromyographic biofeedback, and on-the-job exercise programs. Multiple component interventions (e.g., ergonomic programs) included workstation redesign, establishment of an ergonomics task force, job rotation, ergonomics training, and restricted duty provisions. Multiple component programs were associated with reduced incidence rates of CTS, but the results are inconclusive because they did not adequately control for potential confounders. Several engineering interventions positively influenced risk factors associated with CTS, but the evaluations did not measure disease incidence. None of the personal interventions alone was associated with significant changes in symptoms or risk factors. All of the studies had important methodologic limitations that may affect the validity of the results. CONCLUSIONS While results from several studies suggest that multiple component ergonomics programs, alternative keyboard supports, and mouse and tool redesign may be beneficial, none of the studies conclusively demonstrates that the interventions would result in the primary prevention of carpal tunnel syndrome in a working population. Given the societal impact of CTS, the growing number of commercial remedies, and their lack of demonstrated effec- tiveness, the need for more rigorous and long-term evaluation of interventions is clear. Fund- ing for intervention research should prioritize randomized controlled trials that include: (1) adequate sample size, (2) adjustment for relevant confounding variables, (3) isolation of speci- fic program elements, and (4) measurement of long-term primary outcomes such as the inci- dence of CTS, and secondary outcomes such as employment status and cost.

Using narrative text and coded data to develop hazard scenarios for occupational injury interventions.

Objective: To determine whether narrative text in safety reports contains sufficient information regarding contributing factors and precipitating mechanisms to prioritize occupational back injury prevention strategies. Design, setting, subjects, and main outcome measures: Nine essential data elements were identified in narratives and coded sections of safety reports for each of 94 cases of back injuries to United States Army truck drivers reported to the United States Army Safety Center between 1987 and 1997. The essential elements of each case were used to reconstruct standardized event sequences. A taxonomy of the event sequences was then developed to identify common hazard scenarios and opportunities for primary interventions. Results: Coded data typically only identified five data elements (broad activity, task, event/exposure, nature of injury, and outcomes) while narratives provided additional elements (contributing factor, precipitating mechanism, primary source) essential for developing our taxonomy. Three hazard scenarios were associated with back injuries among Army truck drivers accounting for 83% of cases: struck by/against events during motor vehicle crashes; falls resulting from slips/trips or loss of balance; and overexertion from lifting activities. Conclusions: Coded data from safety investigations lacked sufficient information to thoroughly characterize the injury event. However, the combination of existing narrative text (similar to that collected by many injury surveillance systems) and coded data enabled us to develop a more complete taxonomy of injury event characteristics and identify common hazard scenarios. This study demonstrates that narrative text can provide the additional information on contributing factors and precipitating mechanisms needed to target prevention strategies.

Head, Face, and Eye Injuries in Scholastic and Collegiate Lacrosse A 4-Year Prospective Study

Background Risks and mechanisms of head, face, and eye injuries in high school and college lacrosse are not well documented. Purpose To identify (1) primary mechanisms of head, face, and eye injuries in lacrosse and (2) differences in injury risk between the mens and womens game and between high school and collegiate levels. Study Design Descriptive epidemiological study. Methods The authors gathered data on 507 000 girls’ and boys’ high school and 649 573 womens and mens college lacrosse athletic exposures using sport-specific injury surveillance systems over 4 seasons. They identified the most common scenarios for head, face, and eye injuries. Results The high school girls’ head, face, and eye injury rate (0.54 per 1000 athletic exposures) was significantly higher (incident rate ratio, 1.42; 95% confidence interval, 1.09-1.86) than that for boys (0.38 per 1000 athletic exposures); college women (0.77 per 1000 athletic exposures) sustained a higher rate of injuries (incident rate ratio, 1.76; 95% confidence interval, 1.42-2.19) than did men (0.44 per 1000 athletic exposures). Concussions constituted a higher percentage of injuries among boys (73%) and men (85%) than among girls (40%) and women (41%). Men sustained few facial injuries, whereas a substantial proportion of womens injuries involved the face and orbital area. Conclusion Although permitting only incidental contact, womens lacrosse had higher rates of head, face, and eye injuries at both the high school and collegiate levels. Concussion was the most common injury. For men, the primary injury mechanism was player-to-player contact; womens injuries primarily resulted from stick or ball contact. High school injury rates were lower than were college rates, but the nature of injuries, body parts affected, and mechanisms were similar.

Summary Statement: Appropriate Medical Care for the Secondary School-Aged Athlete

OBJECTIVE To present the recommendations made by the Appropriate Medical Care for Secondary School-Aged Athletes Task Force and to summarize the subsequent monograph developed around 11 consensus points. DATA SOURCES The MEDLINE, CINAHL, and SportDiscus databases were searched for relevant literature regarding secondary school-aged athletes; health care administration; preparticipation physical examination; facilities; athletic equipment; emergency action planning; environmental conditions; recognition, evaluation, and treatment of injuries; rehabilitation and reconditioning; psychosocial consultation; nutrition; and prevention strategies. CONCLUSIONS AND RECOMMENDATIONS Organizations that sponsor athletic programs for secondary school-aged athletes should establish an athletic health care team to ensure that appropriate medical care is provided to all participants. The 11 consensus points provide a framework-one that is supported by the medical literature and case law-for the development of an athletic health care team and for assigning responsibilities to the team, administrators, and staff members of institutions sponsoring secondary school and club-level athletic programs.

Measurement properties of a self-report index of ergonomic exposures for use in an office work environment.

Office work-related upper extremity symptoms and disorders have been associated with static work posture, repetition, and inadequate recovery in the anatomic structures of the neck and upper extremities. Despite these associations, relatively little research has been conducted on the development of practical measures of these ergonomic exposures. The present study examines the measurement properties of an upper-extremity–specific self-report index of ergonomic exposures. Ninety-two symptomatic office workers completed a Web-based questionnaire measuring demographic variables, ergonomic exposures, pain, job stress, and functional limitations. Comparisons of internal consistency, construct validity, and discriminative and predictive abilities were made between the self-report index and an observational exposure assessment checklist. Results indicated that the self-report index had acceptable measurement properties. Furthermore, higher levels of self-reported ergonomic exposures were associated with upper extremity pain, symptom severity, and functional limitations. In contrast, higher levels of observed exposure were related only to lower levels of general physical function. The self-report measure has potential for use in occupational health surveillance programs for office work environments and as an outcome measure of ergonomic exposure in intervention trials. These results also suggest the need for using multiple methods when assessing ergonomic exposures.