Rodney X. Sturdivant

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.

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.

Incidence of de Quervain's Tenosynovitis in a Young, Active Population

PURPOSE De Quervains tenosynovitis is thought to occur most frequently in women, with presentation of pain and swelling in the first dorsal extensor sheath. The epidemiology of this extensor tendinitis is not well described. We evaluated the incidence and demographic risk factors for de Quervains tenosynovitis using a large database of military personnel. METHODS The Defense Medical Epidemiology Database (DMED) collects International Classification of Diseases, 9th Revision, and Clinical Modification (ICD-9-CM) coding information for every patient encounter occurring for United States military personnel. We queried the DMED system by race, gender, military service, rank, and age for the years 1998-2006 using the ICD-9 code 727.04, limiting data to first presentations. Multivariate Poisson regression was used to estimate the rate of de Quervains tenosynovitis per 1000 person-years, as well as incidence rate ratios and 95% confidence intervals. RESULTS There were 11,332 cases of de Quervains tenosynovitis in the population at risk of 12,117,749 person-years. Women had a significantly higher rate of de Quervains tenosynovitis at 2.8 cases per 1000 person-years, compared to men at 0.6 per 1000 person-years. Age greater than 40 was also a significant risk factor, with this age category showing a rate of 2.0 per 1000 person-years compared to 0.6 per 1000 in personnel under 20 years. There was also a racial difference, with blacks affected at 1.3 per 1000 person-years compared to whites at 0.8. CONCLUSIONS In analysis of a large population, we have described the epidemiology of stenosing tenosynovitis of the first extensor compartment. Risk factors for de Quervains in our population include female gender, age greater than 40, and black race. TYPE OF STUDY/LEVEL OF EVIDENCE Prognostic II.

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 patients 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.

Epidemiology of lateral and medial epicondylitis in a military population.

OBJECTIVE To determine the epidemiology of lateral and medial epicondylitis in the U.S. military. METHODS The Defense Medical Epidemiology Database was queried for ICD-9 codes 726.32 (lateral epicondylitis) and 726.33 (medial epicondylitis) for the years 1998-2006. Multivariate Poisson regression was used to calculate incidence rates (IR) and rate ratios (RR) among demographic groups. RESULTS The IRs for lateral and medial epicondylitis were 2.98 and 0.81 per 1000 person-years. For lateral epicondylitis, women had a higher incidence (RR = 1.22, 95% CI 1.19-1.26). In both groups, analysis by age showed higher incidence in the > or = 40-year-old group. White compared with black race was a risk factor for both lateral (RR = 1.68, 95% CI, 1.63-1.74) and medial epicondylitis (RR = 1.11, 95% CI 1.05-1.17). CONCLUSIONS Female gender was a risk factor for lateral but not medial epicondylitis. Age greater than 40 and white race were significant risk factors for both conditions.

Trends in the Incidence of Physician-Diagnosed Mild Traumatic Brain Injury among Active Duty U.S. Military Personnel between 1997 and 2007

Mild traumatic brain injury (mTBI) has been described as the most common form of traumatic brain injury within military populations; however, few epidemiologic studies have examined incidence rates for mTBI in this population. The objective of this study was to examine trends in the incidence of mTBI among active-duty U.S. service members between 1997 and 2007. Specifically, we were interested in evaluating trends in the incidence rates in relation to the initiation of combat operations in Iraq and Afghanistan. A retrospective cohort study was conducted utilizing data extracted from the Defense Medical Surveillance System to identify all incident cases of mTBI within the study population. The primary outcome of interest was the incidence rate of mTBI per 1000 person-years. Multivariable Poisson regression was used to analyze the data. There were 98,012 mTBI cases and 14,956,955 person-years of follow-up, for an overall incidence rate of 6.55 (95% CI 6.51,6.59) per 1000 person-years. There was a steady increase in the mTBI rate over time. The average change in the mTBI rate was 8.5% (95% CI 8.2%,8.8%) per year; however, the rate rose dramatically in the last 2 years of the study period. Overall, for 2006-2007 versus 1997-2005, the rate ratio was 1.61 (95% CI 1.58,1.65). The greatest increase in the rate of mTBI was observed among those serving in Iraq, who experienced a 38.4% (95% CI 35.4%,41.1%) annual increase in new cases. The observed increase in the incidence of mTBI in this population has significant policy implications in terms of allocating appropriate health care resources.

Effects of serial anesthesia using ketamine or ketamine/medetomidine on hematology and serum biochemistry values in rhesus macaques (Macaca Mulatta)

Background  This study aimed at determining the cumulative effect of daily anesthesia, using two drug regimens, over hematological and biochemical parameters.

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

BackgroundJoint 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/purposesWe 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.MethodsWe 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).ResultsWe 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.”ConclusionsIn 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 EvidenceLevel II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Metabolic Effects of Soldier Performance on a Simulated Graded Road March while Wearing Two Functionally Equivalent Military Ensembles

OBJECTIVES The purpose of this study was to examine metabolic effects of soldier performance on a simulated road march, comparing two functionally equivalent military ensembles (FEMEs) with changing gradation of marching, and to create prediction equations addressing workload with different loads and treadmill grades. METHODS Fourteen male military subjects were tested while wearing two different FEMEs on a graded (0%, 5%, or 10%), 3.5 miles/h, road march for 30 minutes. Data collected included oxygen uptake (VO2), carbon dioxide output, ventilation, respiratory exchange ratio, and heart rate (HR). RESULTS No significant differences were found between the two FEMEs in each graded condition. Combining ensemble data, significant differences occurred in all conditions, comparing all grades. A 10% graded road march (3.5 miles/h, approximately 27-kg load) represented 61% to 90% of maximal values. For treadmill grades of <10%, VO2 and HR were modeled as follows (adjusted R2 = 0.89 [VO2] and 0.82 [HR]): VO2 (mL/kg per minute) = 10 + [2 - grade (%)] + [0.2 - load (% of body mass)]; HR (beats per minute) = 90 + [6 . grade (%)] + [0.7 - load (% of body mass)]. CONCLUSIONS Three factors, namely, elevation grade, equipment weight (load), and overall subject physical abilities, were significant for overall metabolic demand during a simulated graded road march and might affect field performance.

Using Classroom Data to Teach Students about Data Cleaning and Testing Assumptions.

This paper discusses the influence that decisions about data cleaning and violations of statistical assumptions can have on drawing valid conclusions to research studies. The datasets provided in this paper were collected as part of a National Science Foundation grant to design online games and associated labs for use in undergraduate and graduate statistics courses that can effectively illustrate issues not always addressed in traditional instruction. Students play the role of a researcher by selecting from a wide variety of independent variables to explain why some students complete games faster than others. Typical project data sets are “messy,” with many outliers (usually from some students taking much longer than others) and distributions that do not appear normal. Classroom testing of the games over several semesters has produced evidence of their efficacy in statistics education. The projects tend to be engaging for students and they make the impact of data cleaning and violations of model assumptions more relevant. We discuss the use of one of the games and associated guided lab in introducing students to issues prevalent in real data and the challenges involved in data cleaning and dangers when model assumptions are violated.