RESUMEN
OBJECTIVE: Biomechanical factors are important treatment targets in knee osteoarthritis. The knee adduction (KAM) and flexion (KFM) moments, quadriceps strength and power, load frequency, and body mass index (BMI) all have the potential to affect knee articular cartilage integrity by modulating forces across the joint. To identify clinically meaningful change, however, these measurements must be reliable and sensitive to change. This study estimated relative and absolute test-retest reliabilities over long periods of biomechanical risk factors for knee osteoarthritis progression. METHOD: Data from a longitudinal, observational study were analyzed for knee osteoarthritis patients with data at baseline, 6-month and 24-month follow-ups. Gait kinematics and kinetics, quadriceps strength and power, daily load frequency and BMI were collected. Relative and absolute test-retest reliabilities of these measures were estimated using intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs), respectively. Minimal detectable change at the 95% confidence level (MDC95) was also calculated. RESULTS: Data from 46 participants [36 women; age 61.0 (6.6) years] were included. Good-to-excellent relative reliabilities (ICC ≥ 0.80) indicated that KAM peak and impulse, quadriceps strength and power, and BMI had a strong ability to discriminate amongst participants. Absolute reliabilities were high for quadriceps strength and BMI, which demonstrated reasonable within-participant variability (SEMs ≤ 11% of the mean). The MDC95 values supported use of clinical interventions effective in reducing BMI and KAM, and increasing quadriceps strength. CONCLUSION: These data are useful in interpreting findings from interventional or longitudinal investigations by determining whether observed changes are beyond measurement error and interpretable as true change.
Asunto(s)
Articulación de la Rodilla/fisiopatología , Osteoartritis de la Rodilla/fisiopatología , Anciano , Benchmarking , Fenómenos Biomecánicos/fisiología , Índice de Masa Corporal , Progresión de la Enfermedad , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Fuerza Muscular/fisiología , Músculo Esquelético/fisiopatología , Pronóstico , Músculo Cuádriceps/fisiopatología , Rango del Movimiento Articular/fisiología , Reproducibilidad de los Resultados , Factores de Riesgo , Soporte de Peso/fisiologíaRESUMEN
Quantification of magnetic resonance (MR)-based relaxation parameters of tendons and ligaments is challenging due to their very short transverse relaxation times, requiring application of ultra-short echo-time (UTE) imaging sequences. We quantify both T1 and T2* in the quadriceps and patellar tendons of healthy volunteers at a field strength of 3â¯T and visualize the results based on 3D segmentation by using bivariate histogram analysis. We applied a 3D ultra-short echo-time imaging sequence with either variable repetition times (VTR) or variable flip angles (VFA) for T1 quantification in combination with multi-echo acquisition for extracting T2*. The values of both relaxation parameters were subsequently binned for bivariate histogram analysis and corresponding cluster identification, which were subsequently visualized. Based on manually-drawn regions of interest in the tendons on the relaxation parameter maps, T1 and T2* boundaries were selected in the bivariate histogram to segment the quadriceps and patellar tendons and visualize the relaxation times by 3D volumetric rendering. Segmentation of bone marrow, fat, muscle and tendons was successfully performed based on the bivariate histogram analysis. Based on the segmentation results mean T2* relaxation times, over the entire tendon volumes averaged over all subjects, were 1.8â¯ms⯱â¯0.1â¯ms and 1.4â¯ms⯱â¯0.2â¯ms for the patellar and quadriceps tendons, respectively. The mean T1 value of the patellar tendon, averaged over all subjects, was 527â¯ms⯱â¯42â¯ms and 476â¯ms⯱â¯40â¯ms for the VFA and VTR acquisitions, respectively. The quadriceps tendon had higher mean T1 values of 662â¯ms⯱â¯97â¯ms (VFA method) and 637â¯ms⯱â¯40â¯ms (VTR method) compared to the patellar tendon. 3D volumetric visualization of the relaxation times revealed that T1 values are not constant over the volume of both tendons, but vary locally. This work provided additional data to build upon the scarce literature available on relaxation times in the quadriceps and patellar tendons. We were able to segment both tendons and to visualize the relaxation parameter distributions over the entire tendon volumes.