Load-bearing in the knee joint.

The surfaces of the knee--anomalous to most animal joints through apparent gross incongruity--would appear more congruous if the menisci bore load. A simple system is used to show how the menisci can bear load. The strong tibial fixation and structure of the menisci, and the geometry of the femoral condyles indicate that the menisci bear load throughout flexion and extension. Confirmatory experimental results show that in partially degenerate human and healthy pigs' knees the menisci bear at least 45 and 75% respectively of the total joint load. The knee joint is similar in this respect to other synovial joints.