Technical considerations in total knee arthroplasty.

Results with total knee arthroplasty as published in this issue show few mechanical failures in knees correctly aligned. If the principles of technique are respected, the narrow limits for margin of error can be met. To provide optimal results, the following measures are recommended. The tibia should be cut no more than 5 mm from the medial subchondral bone, if the posterior cruciate ligament is sacrificed, and between 5 mm and 8 mm, if the posterior cruciate is saved. Fill a defect as necessary with bone graft. The tibia should be cut 90 degrees to its axis in the medial-lateral plane and with 5 degrees posterior tilt. Maintain the anterior-posterior height of the femur to ensure flexion stability. Use the distal femur as the "adjustment cut" even if the joint line is elevated. If the posterior cruciate ligament tension is tight, lengthen the ligament or convert to a sacrificing design. Deformity should be corrected with soft tissue release and not angular bone cuts. The patella cut should be performed so that the result is a symmetrical patella that is not increased from its anatomic height. If these principles are followed, the instrumentation use and order of osteotomy of the distal femur or tibia do not matter.