Individualised total knee arthroplasty demonstrates 99.4% survival at 3 to 5 years

The purpose of this multicentre observational study is to evaluate implant survival and patient-reported outcome measures (PROMs) at 3-5 years following individualised total knee arthroplasty (TKA).

A consecutive series of 426 patients (434 knees) underwent CT-based, posterior-stabilised, cemented, individualised TKA between December 2018 and August 2020. After excluding 73 patients without informed consent, 353 patients (361 knees) were included for survival analysis. A further 74 were excluded (revised = 2, deceased = 11, inadequate follow-up = 61), resulting in a final cohort of 279 patients (287 knees) for PROMs assessment. Implant survival was evaluated using the Kaplan-Meier (KM) method, with revision of any component for any reason as the endpoint at 2- and 3-year follow-ups. Patients completed pre and postoperative questionnaires of the Oxford knee score (OKS) and the forgotten joint score (FJS), and also rated their level of satisfaction on a 4-level Likert scale. The proportion of patients who achieved a patient acceptable symptom state (PASS) was estimated according to the threshold of 30 for OKS and 38 for FJS.

Considering revision for any reason as endpoint, the survival according to the KM method was 99.4% (95%C.I. 98.6%-100.0%) at both 2- and 3-year follow-up. The OKS improved from 22.2 ± 8.4 to 40.6 ± 7.6, and 244 knees (85%) achieved the PASS. The FJS improved from 16.7 ± 14.6 to 68.5 ± 27.7, and 233 (81%) achieved the PASS. Out of the 254 knees with their rated level of satisfaction, 250 (98.4%) were either satisfied or very satisfied.

At 3 to 5 years' follow-up, individualised TKA demonstrated excellent implant survival (99.4%), as well as high patient satisfaction, both considering and disregarding non-respondents (87.1% and 98.4% respectively). The results are promising and warrant continued follow-up to evaluate long-term results.

Level IV.