Joint force analysis in degenerative varus or valgus knees during standing -importance of tibial tilt to the floor-.

A two-dimensional skeletal model of the knee was constructed to estimate joint compression force in varus of valgus osteoarthrotic knees. Angle and length constants and variables were measured for 100 X-ray films of normal and osteoarthrotic subjects while they were standing on one foot. The results showed that the tibial tilting angle to the floor primarily determined the joint forces in the deformed knees. The angle has mechanically more significance than the femoro-tibial tilting angle which has been widely used clinically. The results have some clinical implications.