A case control study comparing mechanically aligned and kinematically aligned total knee arthroplasty in Chinese - Radiographic accuracy and patient-reported outcomes

Abstract

Introduction: We designed a prospective case-control study to compare the radiological and clinical outcomes between MA TKA and KA TKA in Chinese patients. Methodology: 50 patients undergone unilateral TKA were allocated either to MA TKA group (n=18) or KA TKA group (n=32). All surgeries were performed by the same surgeon. Patients were assessed at 6 weeks, 3 months and 6 months post-operatively. Pre-operative patients’ demographics were analyzed. Post-operative lower limb long radiographs were used to assess the lower limb alignment and individual component position. We documented Knee Society Score (KSS), Knee Society Function Assessment (KFA), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Forgotten Knee Score (FKS) at each follow-up. Results and Analysis: All patients completed 6 months follow-up. There is no significant difference in patients’ pre-operative demographics between the MA and KA groups. In the KA group, the post-operative coronal component position accurately matched to pre-operative anatomy (p>0.5). The mean surgical time of KA TKA was 52±8.6 minutes.There is no significant difference found in the knee range of motion, KSS, KFA, KOOS and FKS at pre-op, 6 weeks, 3 months and 6 months post-op between the MA and KA groups. No complication occurred in any patients. Discussion and Conclusion: One can accurately restore the coronal alignment and articular surface anatomy using conventional instruments in KA TKA. The surgical technique is easy to master for an experienced arthroplasty surgeon. We could not demonstrate a significant benefit of KA TKA in early post-operative function and patient-reported outcomes over MA TKA.