Does the femoral head/neck contour in the skeletally mature change over time?

Abstract

The purpose of this study was to determine whetheranterior/anterolateral femoral head/neck contour of the hip is static ordynamic over time within the context of the cam deformity. From apreviously published cohort of 200 asymptomatic patients who had amagnetic resonance imaging (MRI) of their hips, 23 patients wererandomly selected: 10 with a cam lesion and 13 with no evidence of a camlesion in either hip. There were 7 females and 16 males with a mean ageof 37.5 years (range 30-56 years). A repeat MRI or computed tomographyscan was performed. Femoral head/neck contour was assessed with alphaangle measurements at the 3 and 1: 30 positions. At mean time of 5.3years (range 2.5-7.2 years) between the two time points, the mean alphaangle for the entire cohort was not significantly different with alphaangle of 43.4 degrees/53.7 degrees (3:00/1:30 positions) at first visitand 46.1 degrees/54.2 degrees (3:00/1:30 positions) at second visit,respectively. Subdividing the cohort into cam negative and cam positivegroups, there are no clinically relevant differences (i.e. <5 degrees)between the two alpha angle measurements. Inter-observer reliability hadan intra-class coefficient at 0.96 (95% CI: 0.94-0.97). Neither groupof patients demonstrated clinically relevant change in the alpha angle.Consequently, screening at time of skeletal of maturity would be anefficient means of identifying individuals for a possible cam deformity.