Comparison of Tibial Bone Coverage of 6 Knee Prostheses: A Magnetic Resonance Imaging Study with Controlled Rotation

• Main Authors: Gregory C Wernecke, Ian A Harris, Michael TW Houang, Bradley G Seeto, Darren B Chen, Samuel J MacDessi
• Format: Article
• Language: English
• Published: SAGE Publishing 2012-08-01
• Series: Journal of Orthopaedic Surgery
• Online Access: https://doi.org/10.1177/230949901202000201

Purpose. To compare the extent of tibial bone covered by the tibial tray in 6 most commonly used total knee arthroplasty designs in order to strike a balance between mediolateral cortical fit and optimal tibial component rotation. Methods. In 74 men and 27 women aged 17 to 60 (mean, 32) years with suspected soft-tissue injuries, their magnetic resonance images of the knee in full extension were superimposed with scans of the tibial trays of the 6 designs (one asymmetric and 5 symmetric). The tibial coverage by the tray and any posterolateral/posteromedial overhang/underhang were measured. Results. All 6 tray designs achieved tibial bone coverage of over 80%. Only 28% of all trays achieved optimal posterolateral fit, whereas 49% had posterolateral overhang enough to cause popliteal tendon impingement. Although the asymmetric tray provided highest tibial coverage (88%), its rates of relative and absolute posterolateral and posteromedial overhang were also highest (64%). Conclusion. The asymmetric tray provided improved tibial coverage at the expense of posterolateral and posteromedial overhang of the tibial tray.