Occupational driving as a risk factor for low back pain in active-duty military service members.

BACKGROUND CONTEXT: Although occupational driving has been associated with low back pain, little has been reported on the incidence rates for this disorder. PURPOSE: To determine the incidence rate and demographic risk factors of low back pain in an ethnically diverse and physically active population of US military vehicle operators. STUDY DESIGN/SETTING: Retrospective database analysis. PATIENT SAMPLE: All active-duty military service members between 1998 and 2006. OUTCOME MEASURES: Low back pain requiring visit to a health-care provider. METHODS: A query was performed using the US Defense Medical Epidemiology Database for the International Classification of Diseases, Ninth Revision, Clinical Modification code for low back pain (724.20). Multivariate Poisson regression analysis was used to estimate the rate of low back pain among military vehicle operators and control subjects per 1,000 person-years, while controlling for sex, race, rank, service, age, and marital status. RESULTS: A total of 8,447,167 person-years of data were investigated. The overall unadjusted low back pain incidence rate for military members whose occupation is vehicle operator was 54.2 per 1,000 person-years. Compared with service members with other occupations, motor vehicle operators had a significantly increased adjusted incidence rate ratio (IRR) for low back pain of 1.15 (95% confidence interval [CI] 1.13-1.17). Female motor vehicle operators, compared with males, had a significantly increased adjusted IRR for low back pain of 1.45 (95% CI 1.39-1.52). With senior enlisted as the referent category, the junior enlisted rank group of motor vehicle operators had a significantly increased adjusted IRR for low back pain: 1.60 (95% CI 1.52-1.70). Compared with Marine service members, those motor vehicle operators in both the Army, 2.74 (95% CI 2.60-2.89), and the Air Force, 1.98 (95% CI 1.84-2.14), had a significantly increased adjusted IRR for low back pain. The adjusted IRRs for the less than 20-year and more than 40-year age groups, compared with the 30- to 39-year age group, were 1.24 (1.15-1.36) and 1.23 (1.10-1.38), respectively. CONCLUSIONS: Motor vehicle operators have a small but statistically significantly increased rate of low back pain compared with matched control population.

Relationship of relaxin hormone and thumb carpometacarpal joint arthritis.

BACKGROUND: The female predominance in thumb carpometacarpal (CMC) joint arthritis has led to speculation that reproductive hormones or hypermobility are responsible. Evidence shows that patients with pathologic laxity have a higher rate of thumb CMC arthritis. Relaxin hormone increases laxity in the pelvic ligaments through upregulation of matrix metalloproteases (MMPs). It is thus a hormone of interest in the development of thumb CMC arthritis. QUESTIONS/PURPOSES: Our goals were to identify demographic and hormonal factors associated with joint laxity in patients with CMC arthritis and to evaluate the relationship among serum relaxin, relaxin receptors, and MMPs in the anterior oblique ligament (AOL) of the thumb. We hypothesized that serum relaxin was correlated with joint laxity as well as with relaxin receptors and MMPs in the AOL. METHODS: Forty-nine patients undergoing thumb CMC arthroplasty underwent laxity examination, blood draw, and AOL sampling. Ligaments were analyzed for relaxin receptor and MMPs 1 and 3 using quantitative reverse-transcriptase polymerase chain reaction. RESULTS: Women demonstrated more joint laxity than men (p < 0.001). RNA analysis confirmed relaxin receptors in the AOL as well as MMPs 1 and 3. There was a significant correlation between serum relaxin and MMP-1 (p = 0.04). Detectable serum relaxin was negatively correlated with relaxin receptors in the AOL (p = 0.02). CONCLUSIONS: Further studies are needed to evaluate the role of laxity and sex hormones in thumb CMC arthritis. CLINICAL RELEVANCE: Relaxin hormone may play a role in the development of arthritis at the thumb CMC joint. LEVEL OF EVIDENCE: Level I, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Hepatitis C viral infection as an associated risk factor for necrotizing fasciitis.

Necrotizing fasciitis is a rare soft tissue infection associated with a high mortality rate. Several risk factors for the development of necrotizing fasciitis have been studied, which has given surgeons insight into the types of patients who are more likely to present with this rapidly progressive infection. The concomitant diagnosis of hepatitis C viral infection has not been reported in the literature previously. In this retrospective study covering a 12-year period in 1 Level I trauma center, 10 (34%) of 29 patients presenting with necrotizing fasciitis had an underlying diagnosis of hepatitis C viral infection. The mortality rate in patients with hepatitis C viral infection was 30% compared with 21% for those without hepatitis C viral infection (P=.59). The proportion of patients presenting with the concomitant diagnosis of hepatitis C viral infection and necrotizing fasciitis was statistically greater than that expected from the prevalence of hepatitis C viral infection in the general population (1.8%; P<.001).Our study showed that hepatitis C viral infection is a risk factor for developing necrotizing fasciitis. Although our sample size was too small to show a statistical significance, we believe that a clinically significant increase in mortality of necrotizing fasciitis occurred in patients with concomitant hepatitis C viral infection. Therefore, the presence of hepatitis C viral infection in patients presenting with symptoms of necrotizing fasciitis should raise the clinical suspicion for this diagnosis, with the potential for a worse prognosis.

Evaluation of knowledge of common hand surgery problems in internal medicine and emergency medicine residents.

Musculoskeletal disorders are the principal reason for primary care outpatient visits and make up 14% of visits to emergency departments, with the upper extremity as the most common site affected. However, formal musculoskeletal education is inconsistent in medical school and primary care residencies, with many first-year residents reporting a lack of confidence in examination and diagnosis of musculoskeletal conditions. The authors evaluated the level of knowledge of common upper-extremity conditions with a validated examination taken by internal medicine and emergency medicine residents. A 38-question upper-extremity examination was created by a group of hand and upper-extremity surgeons from the Resident Education Committee of the American Society for Surgery of the Hand. The examination was reviewed by 30 hand fellowship directors, who rated each question on a Likert scale and determined a recommended passing percentage. The Web-based examination was taken by emergency and internal medicine residents from multiple institutions. The fellowship directors' recommended passing grade averaged 73%. The majority of respondents were in their first (33%) or second (33%) year of training. The average scores were 56% and 46% for the internal and emergency medicine residents, respectively. This evaluation of a cross-section of internal and emergency residents indicates a deficiency in knowledge of common upper-extremity conditions.

The incidence of low back pain in active duty United States military service members.

STUDY DESIGN: Epidemiological study. OBJECTIVE: To investigate the incidence and risk factors for developing low back pain in active duty military population to include age, sex, race, and rank, and military service. SUMMARY OF BACKGROUND DATA: Low back pain is among the most common musculoskeletal conditions worldwide and is estimated to affect nearly two-thirds of the US population at some point in their lives. Low back pain is a multifactorial disease and many risk factors have been implicated including age, race, sex, and marital status. METHODS: A query was performed using the US Defense Medical Epidemiology Database (DMED) for the International Classification of Diseases, Ninth Revision, Clinical Modification code for low back pain (724.20). 13,754,261 person-years of data were investigated. Multivariate Poisson regression analysis was used to estimate the rate of low back pain per 1000 person-years, whereas controlling for sex, race, rank, service, age, and marital status. RESULTS: The overall unadjusted incidence rate of low back pain was 40.5 per 1000 person-years. Women, compared with men, had a significantly increased incidence rate ratio for low back pain of 1.45. The incidence rate ratio for the 40+ age group compared with the 20 to 29 years of age group was 1.28. With junior officers as the referent category, junior- and senior-enlisted rank groups had increased incidence rate ratio for low back pain, 1.95 and 1.35, respectively. Each service, when compared with the Marines as the referent category, had a significantly increased incidence rate ratio of low back pain: Army: 2.19, Navy: 1.02, and Air Force: 1.54. Compared with single service members, significantly increased incidence rate ratio for low back pain were seen in married service members: 1.21. CONCLUSION: Female sex, enlisted rank groups, service in the Army, Navy, or Air Force, age greater than 40 years, and a marital status of married were all risk factors for low back pain.

Exposure of distal radius fractures using a direct radial approach with mobilization of the superficial branch of the radial nerve.

Extraarticular and simple intraarticular fractures and malunions of the distal radius can be addressed through a direct radial approach that entails careful and meticulous handling of the soft tissues. This approach involves mobilization of the superficial branch of the radial nerve (SBRN) and extensor tendons of the first dorsal compartment. A Type I SBRN pattern is when the nerve presents as a single bundle. In Type II pattern, there are 2 major nerve groups present. With Type II branching patterns of the SBRN, careful intraneural dissection is required to mobilize the nerve branches into a safe location during surgery. The primary advantage of this approach is the ease of surgical dissection and avoidance of the flexor tendons of the fingers during surgery.

Radiographic evaluation of the modified Brunelli technique versus the Blatt capsulodesis for scapholunate dissociation in a cadaver model.

PURPOSE: A variety of soft tissue surgical procedures have been developed for treatment of scapholunate (SL) dissociation. The purpose of this study was to compare the degree of correction obtained (as measured on preoperative and postoperative radiographs) when performing the modified Brunelli technique (MBT) with that of the more commonly performed Blatt capsulodesis (BC) and to evaluate each technique after simulated wrist motion. METHODS: Five cadaver wrists were used for this study. The SL interval, SL angle, and radiolunate angle were recorded radiographically, with the SL ligament intact, for each wrist in several loaded positions: neutral, flexion, extension, radial deviation, ulnar deviation, and clenched fist. The SL interosseous ligament was then completely incised, and the radiographic measurements were repeated to demonstrate SL instability. The radiographic measurements were then repeated after MBT reconstruction and after BC reconstruction. Additional radiographic measurements were taken after simulated wrist motion. RESULTS: Sectioning of the SL ligament resulted in radiographic evidence of SL dissociation. Use of the MBT demonstrated improved correction of the SL interval and the SL angle in the clenched fist position, which was statistically significant when compared with BC. The correction for the SL angle was maintained on the MBT specimens with simulated wrist motion. CONCLUSIONS: The results demonstrate that in this cadaver model, the MBT better restores the normal carpal relationship of the SL interval and SL angle when compared to the BC, as measured on radiographs. This correction might correlate with improved carpal dynamics and improved clinical outcomes.

Case report: Osteonecrosis of the femoral head after hip arthroscopy.

BACKGROUND: Hip arthroscopy is a common orthopaedic procedure used as a diagnostic and therapeutic tool with a multitude of surgical indications. The complication rate is reportedly between 1.3% and 23.3%. Major complications are related to traction, fluid extravasation, and iatrogenic chondral injury. Although osteonecrosis is a concern with any surgical procedure about the hip, this complication has been primarily a theoretical concern with hip arthroscopy. CASE DESCRIPTION: We report the case of a 24-year-old man who presented with a 2-year history of left hip pain. He underwent hip arthroscopy to include débridement of a torn labrum and removal of a prominent pincer lesion for femoroacetabular impingement. Traction was initiated by applying manual traction to the traction bar until 10 mm of joint distraction was obtained. Traction was removed at 90 minutes. At the 3-month followup, MRI showed osteonecrosis in the subcapital region of the left femoral head. LITERATURE REVIEW: It generally is agreed the magnitude and duration of traction during hip arthroscopy increase the risk of traction-related injuries. Only one previous case of femoral head osteonecrosis associated with hip arthroscopy has been reported, and this may have resulted from the initial traumatic event. Based on anatomic studies, the use of standard arthroscopic portals would not put at risk any dominant normal vascular structures supplying the femoral head. In contrast, the literature shows that femoral head osteonecrosis may develop secondary to a combination of increased intraarticular pressure and traction. PURPOSES AND CLINICAL RELEVANCE: We suspect this case of femoral head osteonecrosis after hip arthroscopy was caused by traction used in the procedure.

Incidence of joint hypermobility syndrome in a military population: impact of gender and race.

BACKGROUND: Joint hypermobility syndrome is defined by abnormal laxity in multiple joints in association with symptomatic joint pain. Previous studies in small populations suggest a predominance of female gender and nonwhite race among those diagnosed with hypermobility syndrome. QUESTIONS/PURPOSES: We investigated the epidemiology of joint hypermobility in a large military population, presuming this syndrome would be less prevalent in this specialized population but that demographic analysis would reveal risk factors for this rare condition. METHODS: We queried the Defense Medical Epidemiology Database by race, gender, military service, and age for the years 1998 to 2007 using the International Classification of Diseases, 9th Revision code 728.5 (hypermobility syndrome). RESULTS: We identified 790 individuals coded for joint hypermobility syndrome among a population at risk of 13,779,234 person-years for a raw incidence rate of 0.06 per 1000 person-years. Females had a higher incidence rate for joint hypermobility syndrome compared with males. Racial stratification showed service members of white race had higher rates of joint hypermobility syndrome compared with service members categorized as black and "other." CONCLUSIONS: In a large, established military database it appears joint hypermobility syndrome is a rare condition within the young, active population we studied and female gender is the most important risk factor. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

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.

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.