Gap Balancing, Measured Resection, and Kinematic Alignment: How, When, and Why?

Abstract

» Although total knee arthroplasty is a successful and well-established surgical intervention, there is renewed interest in evaluating its theoretical underpinning and surgical techniques in order to identify areas for potential improvement in patient outcomes.» The practice of using mechanical limb alignment for total knee arthroplasty arose from the design of the modern condylar knee prosthesis, with the goal of equally distributing stresses across the articulating surfaces of the prosthesis.» With the kinematic alignment technique, the restoration of normal joint kinematics is based on 3 goals: (1) restoring the native tibiofemoral articular surfaces, (2) restoring the native limb and knee alignment, and (3) restoring the native laxity of the knee.» With the gap-balancing technique, knee balance is primarily achieved through osseous resection and removal. Ligament releases may be necessary prior to completion of the bone resections in order to correct fixed deformities or to restore neutral mechanical alignment before determining component rotation.» With measured resection, either the femur or the tibia can be resected first and in its entirety because all bone resections are independent of one another. Bone resections are fixed on the basis of osseous landmarks, implant dimensions, and patient anatomy.