A surgical leg positioner capable of bending the knee in varus or valgus while simultaneously distracting the tibia from the femur, the leg positioner having a thigh clamp module, a swing arm module connected to the thigh clamp module in a manner that offsets a joint axis laterally to the side of the knee of the patient so as not to damage the opposite compartment of the knee when bent in varus or valgus. The swing arm module also distracts the knee simultaneously when the knee is bent in varus or valgus. The swing arm module also permits flexion and extension of the knee at the knee's natural flexion-extension axis. The surgical leg positioner also utilizes a thigh brace that properly aligns the leg on the surgical leg positioner.