Kinematics of the Knee After Partial and Total Knee Arthroplasty

Total knee arthroplasty (TKA) is considered an extremely successful surgical procedure for treating end-stage arthritis of the knee, with excellent long-term survivorship. Many biomechanical studies of native and artificial knees, performed under both weight-bearing and non-weight-bearing conditions, have shown that the kinematics of total knee replacements (TKRs) differs significantly from those of the native joint (Casino et al., J Orthop Res, 27: 202-207, 2009; Heyse et al., Knee Surg Sports Traumatol Arthrosc, 22: 1902-1910, 2014; Price et al., J Arthroplasty, 19: 590-597, 2004; Victor et al., J Bone Joint Surg Am, 91: 150-163, 2009; Yoshiya et al., J Arthroplasty, 20: 777-783, 2005). This may contribute to early implant failure by aseptic loosening, excessive polyethylene wear, and damage to supporting soft-tissue structures. Changes in joint kinematics during daily activities may also help explain why 15-20% of the patients undergoing TKA are dissatisfied with the function of their operative knee (Casino et al., J Orthop Res, 27: 202-207, 2009; Price et al., J Arthroplasty, 19: 590-597, 2004; Argenson, J Bone Joint Surg Am, 84-A: 2235-2239, 2002; Ettinger et al., Arch Orthop Trauma Surg, 135: 871-877, 2015; Jones et al., Bone Joint J, 98-B: 16-21, 2016). The kinematics of the knee joint after TKA or unicompartmental knee arthroplasty (UKA) depends on several factors including implant design, surgical technique, and component position. A good understanding of the effect of different implant designs on knee kinematics is critical to optimizing surgical techniques and outcomes for patients following arthroplasty. Understanding and interpreting these kinematic studies are important for future implant design and optimizing patient outcomes. This chapter reviews the kinematics of the knee before and after total and unicompartmental knee replacement and the role of implant design.