The measurement of focal diurnal variation in the femoral articular cartilage of the knee

Abstract

Our objective was to test the hypothesis that focal diurnal changes occur in the femoral articular cartilage of the knee in asymptomatic young adults. Six volunteers each were scanned early in the morning, and at the end of a working day spent mainly standing. This protocol was repeated on three successive weeks. Femoral cartilage segmentations were obtained using a region-growing algorithm. These segmentations then were regridded onto a 500-pixel template, and differences in the resulting thickness maps were assessed. Analysis of variance showed no significant diurnal variation in mean thickness. There were, however, statistically-significant diurnal changes in the thickness maps. Cartilage thickness decreased during the day in three specific locations which suffer the greatest biomechanical force.