Functional Impairment Is a Risk Factor for Knee Replacement in the Multicenter XXXX Study.

@entity1 @entity626 @entity571 @entity158
BACKGROUND: @entity158 associated with @entity626 ( @entity571 ) often leads @entity1 to seek and complete total knee arthroplasty (TKA). To date, few studies have evaluated the relation of functional impairment to the risk of TKA, despite the fact that @entity571 is associated with functional impairment. QUESTIONS/PURPOSES: The purpose of our study was to (1) evaluate whether function as measured by WOMAC physical function subscale was associated with undergoing TKA; and (2) whether any such association varied by sex. METHODS: The National Institutes of Health-funded Multicenter @entity571 Study (MOST) is an observational cohort study of @entity1 aged 50 to 79  years with or at high risk of symptomatic knee @entity571 who were recruited from the community.  All eligible subjects with complete data were included in this analysis. Our study population sample consisted of 2946 @entity1 with 5796 knees; 1776 (60%) of @entity1 were @entity1 . We performed a repeated-measures analysis using baseline WOMAC physical function score to predict the risk of TKA from baseline to 30  months and WOMAC score at 30  months to predict risk of incident TKA from 30  months to 60  months. We used generalized estimating equations to account for the correlation between two knees within an individual and across the two periods. We calculated relative risk (RR) of TKA over 30  months by WOMAC function using a score of 0 to 5 as the referent in multiple binomial regressions with log link. RESULTS: Those with the greatest functional impairment (WOMAC scores 40-68; 62 TKAs in 462 knee periods) had 15.5 times (95% confidence interval [CI], 7.6-31.8; p  <  0.001) the risk of undergoing TKA over 30  months compared with the referent group (12 TKAs in 3604 knee periods), adjusting for basic covariates, and 5.9 times (95% CI, 2.8-12.5; p  <  0.001) the risk after further adjusting for knee @entity158 severity. At every level of functional limitation, the RR for TKA for @entity1 was higher than for @entity1 , but interaction with sex did not reach significance after adjustment for covariates including @entity158 (p  =  0.138). CONCLUSIONS: Baseline physical function appears to be an important element in @entity1 considering TKA. Future studies should examine whether interventions to improve function can reduce the need for TKA. LEVEL OF EVIDENCE: Level III, observational cohort study.
