Mid-term functional outcomes of patient-specific versus conventional instrumentation total knee arthroplasty: a prospective study

Introduction Patient-specific instrumentation (PSI) utilizes three-dimensional imaging to produce total knee arthroplasty cutting jigs which matches patient’s native anatomy. However, there are limited mid- to long-term studies examining its clinical efficacy. The aim of this study was to compare functional outcomes of PSI surgery versus conventional TKA surgery at 5-year follow-up. Materials and methods Sixty patients were prospectively recruited into either the MRI-based PSI or conventional TKA group. Functional outcomes were assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS) and Oxford Knee Score (OKS), while quality of life was evaluated with the Physical Component Score (PCS) and Mental Component Score (MCS) of Short-Form 36 and compared between the two groups at 5-year follow-up. Results Although the PCS was 7 ± 3 points better in the PSI group preoperatively ( p = 0.017), it became 5 ± 2 points worse than the conventional group at 5-year follow-up ( p = 0.025). As compared to the PSI group, the conventional group showed a significantly greater improvement in PCS at 5 years as compared to before surgery ( p = 0.003). There were no significant differences in KSFS, KSKS, OKS or MCS between the two groups. Conclusions PSI TKA did not result in improved functional outcomes or better quality of life when compared to conventional TKA. The additional costs and waiting time associated with PSI are not justifiable and therefore not recommended as an alternative to conventional TKA. Level of evidence II.