Instrumentation pitfalls: you just can't go on autopilot!

Instrumentation for total knee arthroplasty is crucial for proper positioning and orientation of the components. Instruments, however, must be used properly if the surgeon is to accomplish the goals. The entrance point for intramedullary guides for both the femur and tibia should not be arbitrarily chosen but picked after evaluation of the intersection of the anatomic axes of the respective bones with their articular surfaces. Saw blades must be held on cutting blocks, and the blocks themselves affixed to bones with sufficient pins to assure stability. If an extramedullary tibial alignment guide is chosen, its distal position should be in the center of the ankle plafond, not in the mid-malleolar point. In the lateral plane, it should parallel the shaft of the fibula. Femoral component rotation cannot always be judged from the posterior condylar tangent line. There may be difficulties of deformity with bone and cartilage loss, especially in valgus knees. Surgeons need to be mindful of the epicondylar axis and the midtrochlear of the anteroposterior axis of Whiteside.