The effects of computer navigation and patient-specific instrumentation on risk of revision, PROMs, and mortality following primary TKR

Background: Computer navigation and patient-specific instrumentation have been in use over the past 2 decades for total knee replacement (TKR). However, their effects on implant survival and patient-reported outcomes remain under debate. We aimed to investigate their influence on implant survival, outcomes of the Oxford Knee Score (OKS) and health-related quality of life (EQ-5D-3L), intraoperative complications, and postoperative mortality compared with conventional instrumentation, across a real-world population.

Methods: This observational study used National Joint Registry (NJR) data and included adult patients who underwent primary TKR for osteoarthritis between April 1, 2003, and December 31, 2020. The primary analysis evaluated revision for all causes, and secondary analyses evaluated differences in the OKS and EQ-5D-3L at 6 months postoperatively, and mortality within 1 year postoperatively. Weights based on propensity scores were generated, accounting for several covariates. A Cox proportional hazards model was used to assess revision and mortality outcomes. Generalized linear models were used to evaluate differences in the OKS and EQ-5D-3L. Effective sample sizes were computed and represent the statistical power comparable with an unweighted sample.

Results: Compared to conventional instrumentation, the hazard ratios (HRs) for all-cause revision following TKR performed using computer navigation and patient-specific instrumentation were 0.937 (95% confidence interval [CI], 0.860 to 1.021; p = 0.136; effective sample size [ESS] = 91,607) and 0.960 (95% CI, 0.735 to 1.252; p = 0.761; ESS = 13,297), respectively. No differences were observed in the OKS and EQ-5D-3L between conventional and computer-navigated TKR (OKS, −0.134 [95% CI, −0.331 to 0.063]; p = 0.183; ESS = 29,135; and EQ-5D-3L, 0.000 [95% CI, −0.005 to 0.005]; p = 0.929; ESS = 28,396) and between conventional TKR and TKR with patient-specific instrumentation (OKS, 0.363 [95% CI, −0.104 to 0.830]; p = 0.127; ESS = 4,412; and EQ-5D-3L, 0.004 [95% CI, −0.009 to 0.018]; p = 0.511; ESS = 4,285). Mortality within 1 year postoperatively was similar between conventional instrumentation and either computer navigation or patient-specific instrumentation (HR, 1.020 [95% CI, 0.989 to 1.052]; p = 0.212; ESS = 110,125).

Conclusions: On the basis of this large registry study, we conclude that computer navigation and patient-specific instrumentation have no statistically or clinically meaningful effect on the risk of revision, patient-reported outcomes, or mortality following primary TKR.

Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.