Optimal correction in high tibial osteotomy for varus deformity.

As a basis for determining the required correction in high tibial osteotomy a measurement of the laterl angle between the axes of the femur and the tibia on standing films is not sufficiently reliable, because the knee can be maintained in various positions through muscular action. When the three-point technique is applied the medio-lateral instability of the knee joint can be determined and by using the varus/valgus deviation as measured in this way the desired correction can be calculated. For this patient series it was found that correction to between 3 and 7 degrees valgus of the varus/valgus deviation (three-point technique) led to the best subjective ratng of the end result by the patients. To compensate for the expected subjective relapse after the operation another 1 or 2 degrees may be added to the angular change at the operation. To avoid an increase in the instability of the knee a lateral capsule reconstruction should be performed.