Accuracy of a patient-specific instrumentation for coronal plane alignment of an anatomic alignment total knee arthroplasty system: A radiographic study.

Abstract

Patient-individualised anatomic alignment in total knee arthroplasty (TKA) requires exact positioning of the tibial and femoral components. Patient-specific instrumentation (PSI) may be advantageous for implantation. However, the role of PSI in the instrumentation of such knee designs has not been investigated. The aim of this study was to investigate the accuracy of a PSI system designed for patient-individualised anatomic alignment. Fifty-four patients from a single centre were consecutively enrolled in this study. Patient-specific femoral and tibial cutting guides were manufactured using 3D models from computed tomography (CT) scans. All patients received an anatomic TKA implant design through an extension gap first technique. Postoperative radiography was taken, and implant component alignment and leg alignment were compared to the preoperative planning. Thirty-four patients were evaluable. Mean differences between planned angles values obtained from CT scans and the measured radiographic values were small and not significantly different from zero. Implantation of an anatomic knee design that allows individual component alignment using PSI is feasible. The percentage of component misalignment in the coronal plane was remarkably low. Whether this leads to clinical benefits requires further verification.