TIBIOFEMORAL CONTACT PRESSURES IN DEGENERATIVE JOINT DISEASE

Using tibiofemoral joints from older (age, 53-80 years) human cadavers with articular cartilage degeneration, contact pressures and contact areas were measured in the extended knee in four conditions: (1) neutr al alignment; (2) 5 degrees varus (simulating single limb stance of ga it); (3) 5 degrees valgus; and (4) after a 5 degrees proximal tibial c losing wedge valgus osteotomy. In degenerated cartilage, contact press ures were reduced at the lesion sites and were high on the borders of the lesions. No statistically significant changes occurred in contact pressures and areas when values from neutral loading were compared wit h values during loading in each of the other three conditions. Lateral average and maximum contact pressures were less in varus loading than in valgus loading, Equal medial and lateral contact pressures during varus loading, in contrast to lower medial than lateral contact pressu res in the other three loadings, supports the theory that the varus mo ment imposed on the knee in single limb stance could be a mechanism ca using medial tibiofemoral osteoarthritis. The 5 degrees valgus osteoto my resulted in contact pressures similar to those in neutral loading. These experiments do not support the value of the 5 degrees valgus ost eotomy in reducing contact pressures on the medial tibial plateau.