Photoelastic analysis of stress distribution on the tibiofemoral joint after meniscectomy.

Abstract

Three-dimensional photoelasticity models of the knee joints were made of epoxy to observe the change in the status of stresses according to the size of defect in the meniscus. Three kinds of meniscus models were made of rubber. Through axial application of a vertical compressive load of 8 kg, equivalent to the joint reaction of 3000 N in the human knee joint, the patterns of the isochromatic fringes were observed and stresses around the knee joint were analyzed according to the size of the defect in the medial meniscus. Stress was increased in magnitude according to the size of the defect of the meniscus, and was focalized after meniscectomy. In the partial meniscectomy model, the maximum stress concentration point of the removed side migrated to the margin of the same side of the joint. But, in the total meniscectomy model, stresses were markedly increased in magnitude on both sides of joints, and maximum stress concentration points were more centralized. This centralization effect would contribute to the degenerative process of the knee joint after meniscectomy.