Subchondral bone strength in arthrosis. Cadaver studies of tibial condyles.

We measured the axial penetration strength of subchondral cancellous bone in a close, regular pattern at the tibial resection surface of five valgus and seven varus human, cadaveric knees. The strength patterns obtained were illustrated by pseudo-three-dimensional reconstructions of strength values as a function of the location on the resection surface. The varus knees had high strength values towards the medial margin of the medial condyle. Three qualitatively different strength patterns were distinguished in the valgus knees: two knees showed a near normal strength distribution with higher peak values medially; two knees with centrolateral bony attrition had high bone strength values at the center of the lateral condyle; and one knee with moderate posterolateral bony attrition showed a high strength area at the posterolateral aspect of the lateral condyle. In both types of malalignment, there was a decrease of bone strength with the depth from the resection surface.