Validation of varus stress radiographs for anterior cruciate ligament and posterolateral corner knee injuries: A biomechanical study.

PURPOSE: The purpose of this study was to determine the effect of isolated anterior cruciate ligament (ACL) insufficiency on the radiographic varus stress test, and to provide reference data for the increase in lateral compartment opening under varus stress for a combined ACL and PLC injury. METHODS: Ten cadaveric lower extremities were fixed to a jig in 20° of knee flexion. Twelve Newton-meter (Nm) and clinician-applied varus loads were tested, first with intact knee ligaments, followed by sequential sectioning of the ACL, fibular collateral ligament (FCL), popliteus tendon and the popliteofibular ligament (PFL). Lateral compartment opening was measured after each sequential sectioning. RESULTS: Maximum increase in lateral compartment opening for an isolated ACL deficient knee was 1.06mm with mean increase of 0.52mm (p=0.021) for the clinician-applied load. Mean increase in lateral compartment opening in an ACL and FCL deficient knee compared to the intact knee was 1.48mm (p<0.005) and 1.99mm (p<0.005) for the 12-Nm and clinician-applied loads, respectively, increasing to 1.94mm (p<0.005) and 2.68mm (p<0.005) with sectioning of the ACL and all PLC structures. CONCLUSIONS: Anterior cruciate ligament deficiency contributes to lateral compartment opening on varus stress radiographs though not sufficiently to confound previously established standards for lateral ligament knee injuries. We did not demonstrate the same magnitude of lateral compartment opening with sectioning of the PLC structures as previously reported, questioning the reproducibility of varus stress radiographic testing among institutions. Clinicians are cautioned against making surgical decisions based solely on current standards for radiographic stress examinations.

Clinical and imaging assessment of acute combat mild traumatic brain injury in Afghanistan.

OBJECTIVE: To evaluate whether diffusion tensor imaging (DTI) will noninvasively reveal white matter changes not present on conventional MRI in acute blast-related mild traumatic brain injury (mTBI) and to determine correlations with clinical measures and recovery. METHODS: Prospective observational study of 95 US military service members with mTBI enrolled within 7 days from injury in Afghanistan and 101 healthy controls. Assessments included Rivermead Post-Concussion Symptoms Questionnaire (RPCSQ), Post-Traumatic Stress Disorder Checklist Military (PCLM), Beck Depression Inventory (BDI), Balance Error Scoring System (BESS), Automated Neuropsychological Assessment Metrics (ANAM), conventional MRI, and DTI. RESULTS: Significantly greater impairment was observed in participants with mTBI vs controls: RPCSQ (19.7 ± 12.9 vs 3.6 ± 7.1, p < 0.001), PCLM (32 ± 13.2 vs 20.9 ± 7.1, p < 0.001), BDI (7.4 ± 6.8 vs 2.5 ± 4.9, p < 0.001), and BESS (18.2 ± 8.4 vs 15.1 ± 8.3, p = 0.01). The largest effect size in ANAM performance decline was in simple reaction time (mTBI 74.5 ± 148.4 vs control -11 ± 46.6 milliseconds, p < 0.001). Fractional anisotropy was significantly reduced in mTBI compared with controls in the right superior longitudinal fasciculus (0.393 ± 0.022 vs 0.405 ± 0.023, p < 0.001). No abnormalities were detected with conventional MRI. Time to return to duty correlated with RPCSQ (r = 0.53, p < 0.001), ANAM simple reaction time decline (r = 0.49, p < 0.0001), PCLM (r = 0.47, p < 0.0001), and BDI (r = 0.36 p = 0.0005). CONCLUSIONS: Somatic, behavioral, and cognitive symptoms and performance deficits are substantially elevated in acute blast-related mTBI. Postconcussive symptoms and performance on measures of posttraumatic stress disorder, depression, and neurocognitive performance at initial presentation correlate with return-to-duty time. Although changes in fractional anisotropy are uncommon and subtle, DTI is more sensitive than conventional MRI in imaging white matter integrity in blast-related mTBI acutely.

Prevalence and factors associated with liver test abnormalities among human immunodeficiency virus-infected persons.

BACKGROUND & AIMS: Liver disease is a major cause of morbidity and mortality among human immunodeficiency virus (HIV)-infected persons. We evaluated the prevalence, etiology, and factors associated with liver dysfunction in patients during the highly active antiretroviral therapy era. METHODS: We performed liver tests (baseline and after a 6-month follow-up period) in HIV-infected patients treated at a large clinic. Comprehensive laboratory and ultrasound analyses were performed. Factors associated with liver test abnormalities were assessed using multivariate logistic regression models. RESULTS: Eighty of 299 HIV-positive patients (27%) had abnormal liver test results during the 6-month study period. The majority of abnormalities were grade 1. Of those with liver test abnormalities, the most common diagnosis was nonalcoholic fatty liver disease (30%), followed by excessive alcohol use (13%), chronic hepatitis B (9%), chronic active hepatitis C (5%), and other (hemochromatosis and autoimmune hepatitis, 2%); 8 participants (10%) had more than 1 diagnosis. In total, 39 HIV patients with abnormal liver test results (49%) had a defined underlying liver disease. Despite laboratory tests and ultrasound examination, 41 abnormal liver test results (51%) were unexplained. Multivariate analyses of this group found that increased total cholesterol levels (odds ratio, 1.6 per 40-mg/dL increase; P = .01) were associated with liver abnormalities. CONCLUSIONS: Liver test abnormalities are common among HIV patients during the highly active antiretroviral therapy era. The most common diagnosis was nonalcoholic fatty liver disease. Despite laboratory and radiologic investigations into the cause of liver dysfunction, 51% were unexplained, but might be related to unrecognized fatty liver disease.

Nonalcoholic fatty liver disease among HIV-infected persons.

OBJECTIVE: To describe the prevalence and factors associated with nonalcoholic fatty liver disease (NAFLD) among HIV-infected persons not infected with hepatitis C virus (HCV). DESIGN: : A cross-sectional study among HIV-infected patients in a large HIV clinic. METHODS: NAFLD was defined as steatosis among patients without viral hepatitis (B or C) coinfection or excessive alcohol use. The prevalence of NAFLD was identified by ultrasound examination evaluated by 2 radiologists blinded to the clinic information; liver biopsies were performed on a subset of the study population. Factors associated with NAFLD were evaluated by proportional odds logistic regression models. RESULTS: Sixty-seven of 216 patients (31%) had NAFLD based on ultrasound evaluation. Among those with NAFLD, steatosis was graded as mild in 60%, moderate in 28%, and severe/marked in 12%. Factors associated with the degree of steatosis on ultrasound examination in the multivariate model included increased waist circumference [odds ratio (OR) 2.1 per 10 cm, P < 0.001], elevated triglyceride levels (OR 1.2 per 100 mg/dL, P = 0.03), and lower high-density lipoprotein levels (OR 0.7, per 10 mg/dL, P = 0.03). African Americans were less likely to have NAFLD compared with whites (14% vs. 35%), although this did not reach statistical significance (OR 0.4, P = 0.08). Similar associations were noted for the subset of patients diagnosed by liver biopsy. CD4 cell count, HIV viral load, duration of HIV infection, and antiretroviral medications were not independent risk factors associated with NAFLD after adjustment for dyslipidemia or waist circumference. CONCLUSIONS: NAFLD was common among this cohort of HIV-infected HCV-seronegative patients. NAFLD was associated with a greater waist circumference, low high-density lipoprotein, and high triglyceride levels. Antiretroviral medications were not associated with NAFLD; prospective studies are needed to confirm this finding.

Wall thickening of the gastric antrum as a normal finding: multidetector CT with cadaveric comparison.

OBJECTIVE: The purpose of this study was to establish the normal range of wall thickness and the normal appearance of the gastric antrum on multidetector CT (MDCT). METHODS: AND MATERIALS. Soft-copy measurements of the gastric antrum and gastric body were performed on contrast-enhanced MDCT scans in 153 consecutive patients without gastric disease. For comparison, anatomic dissection of the stomach was performed in three cadavers. RESULTS: Smooth thickening of the distal gastric antrum relative to the proximal stomach on MDCT was seen in 152 (99%) of 153 patients and appeared concentric in 96% and eccentric in 4%. The mean (+/- SD) antral wall thickness was 5.1 +/- 1.6 mm. The longitudinal extent of antral wall thickening averaged 4.6 cm. At least one antral wall measurement (anterior or posterior) exceeded 5 and 10 mm in 85 patients (56%) and seven patients (5%), respectively. The anterior wall of the gastric body was significantly thinner at 2.0 +/- 0.4 mm (mean +/- SD) than the wall of the gastric antrum (p << 0.0001). The mean antral wall thickness when distention was characterized as grade 1 (least), 2, 3, and 4 (most) was 6.9, 5.1, 4.9, and 4.0 mm, respectively. Linear submucosal low attenuation (mural striation) of the thickened portion of the gastric antrum was noted in 36 patients (24%); fat attenuation was present in 14 cases. Cadaveric stomachs showed mild segmental thickening of the distal gastric antrum, but this thickening was less pronounced compared with in vivo MDCT findings. CONCLUSION: Smooth wall thickening of the distal gastric antrum relative to the proximal stomach on MDCT with or without submucosal low attenuation is a normal finding. Antral wall thickness commonly exceeds 5 mm and may measure up to 12 mm. Our MDCT findings, in conjunction with previous anatomic and physiologic observations, suggest that normal antral wall thickening consists of both static and dynamic components.