Long-term stress distribution patterns of the ankle joint in varus knee alignment assessed by computed tomography osteoabsorptiometry

摘要

Purpose: The stress distribution of an ankle under various physiological conditions is important for long-term survival of total ankle arthroplasty. The aim of this study was to measure subchondral bone density across the distal tibial joint surface in patients with malalignment/instability of the lower limb. Methods: We evaluated subchondral bone density across the distal tibial joint in patients with malalignment/instability of the knee. Subchondral bone density of the ankle was measured by computed tomography (CT) osteoabsorptiometry from ten ankles as control and from 27 ankles with varus deformity/instability of the knee. The quantitative analysis focused on the location of the high-density area at the articular surface, to determine the resultant long-term stress on the ankle joint. Results: The area of maximum density of subchondral bone was located in the medial part in all subjects. The pattern of maximum density in the anterolateral area showed stepwise increases with the development of varus deformity/instability of the knee. Conclusions: Our results should prove helpful for designing new prostheses and determining clinical indications for total ankle arthroplasty.