Fig. 3From: Patient-specific instrumentation combined with a new tool for gap balancing is useful in total knee replacement: a 3-year follow-up of a retrospective studyThe lower extremity long-standing radiograph and positive X-ray with preoperative and postoperative alignment (red line). HKA is defined as the angle between a line from the femoral head center to the tibial spine center and a line from the tibial spine center to the talus joint surface centre (a, b). The method of measuring the change of joint line before and after operation with the insertion point of the adductor femur as the reference point (c, d)Back to article page