How does laxity after single radius total knee arthroplasty compare with the native knee?

• Published in: Journal of orthopaedic research 2014-09, Vol.32 (9), p.1208-1213
• Main Authors: Hunt, Nicola C., Ghosh, Kanishka M., Blain, Alasdair P., Athwal, Kiron K., Rushton, Steve P., Amis, Andrew A., Longstaff, Lee M., Deehan, David J.
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Arthroplasty, Replacement, Knee; Biomechanical Phenomena; biomechanics; Cadaver; cruciate retaining; Female; Humans; Joint Instability - physiopathology; Knee Joint - physiology; Knee Joint - surgery; knee replacement; Male; Middle Aged; navigation; Range of Motion, Articular - physiology; stability; Surgery, Computer-Assisted; Weight-Bearing - physiology
• ISSN: 0736-0266; 1554-527X
• DOI: 10.1002/jor.22645

ABSTRACT Patients with total knee arthroplasties (TKAs) continue to report dissatisfaction in functional outcome. Stability is a major factor contributing to functionality of TKAs. Implants with single‐radius (SR) femoral components are proposed to increase stability throughout the arc of flexion. Using computer navigation and loaded cadaveric legs, we characterized the “envelope of laxity” (EoL) offered by a SR cruciate retaining (CR)‐TKA compared with that of the native knee through the arc of flexion in terms of anterior drawer, varus/valgus stress, and internal/external rotation. In both the native knee and the TKA laxity increased with increasing knee flexion. Laxities measured in the three planes of motion were generally comparable between the native knee and TKA from 0° to 110° of flexion. Our results indicate that the SR CR‐TKA offers appropriate stability in the absence of soft tissue deficiency. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1208–1213, 2014.