Selective ligament release in total knee arthroplasty of the knee in valgus.

An approach to the valgus knee based on anatomic function of ligaments in flexion and extension consistently yields a knee that is balanced in flexion and extension when the implants have been positioned correctly. Two hundred thirty-one knees had a valgus deformity (range, 12 degrees-45 degrees) and were corrected with valgus alignment to 5 degrees by resecting the intact joint surfaces to match implant thickness. Femoral joint surfaces were aligned in 5 degrees valgus to the long axis of the femur and parallel to the epicondylar axis of the femur in flexion and extension. The tibial surfaces were aligned perpendicular to the long axis of the tibia. For knees that were tight in flexion and extension, the lateral collateral ligament and popliteus tendon were released. Those knees that remained tight only in extension had release of the iliotibial band. Posterior capsular release was done only when necessary for persistent lateral ligament tightness. Neither ligament advancement procedures nor varus or valgus stabilized implant systems were needed to achieve stability with this procedure. The knees with ligament releases all fell within a range of 4 degrees to 7 degrees mean varus and valgus laxity, and were not significantly different from one another. No cases of clinical instability occurred, and joint stability did not deteriorate with time.