Functional Impairment Is a Risk Factor for Knee Replacement in the Multicenter Osteoarthritis Study.
Barton L Wise1, Jingbo Niu, David T Felson
1Center for Musculoskeletal Health, University of California, Davis School of Medicine, 4625 2nd Avenue, Suite 2000, Sacramento, CA, 95817, USA, barton.wise@ucdmc.ucdavis.edu.
Clinical Orthopaedics and Related Research
|March 11, 2015
Summary
Severe functional impairment in knee osteoarthritis significantly increases the risk of total knee arthroplasty (TKA). Improving physical function may reduce the need for TKA surgery.
Area of Science:
- Orthopedics and Sports Medicine
- Rheumatology
- Public Health
Background:
- Knee osteoarthritis (OA) frequently causes debilitating pain, leading many patients to undergo total knee arthroplasty (TKA).
- The relationship between functional impairment and TKA risk in OA patients remains under-investigated, despite OA's known association with functional limitations.
Purpose of the Study:
- To assess if physical function, measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale, predicts the likelihood of TKA.
- To determine if the association between physical function and TKA risk differs between sexes.
Main Methods:
- Analysis of data from the Multicenter Osteoarthritis Study (MOST), an observational cohort study of 2946 individuals aged 50-79 with symptomatic knee OA.
- Repeated-measures analysis using baseline and 30-month WOMAC physical function scores to predict TKA risk over 30-month and 30-60 month intervals, respectively.
- Generalized estimating equations were used to account for correlated data within individuals, and relative risk (RR) of TKA was calculated using logistic regression.
Main Results:
- Patients with the highest functional impairment (WOMAC scores 40-68) had a 15.5-fold increased risk of TKA within 30 months compared to those with minimal impairment (score 0-5).
- This association remained significant (5.9-fold increased risk) even after adjusting for knee pain severity.
- While women consistently showed a higher relative risk for TKA across all functional limitation levels, the interaction with sex did not reach statistical significance after covariate adjustment.
Conclusions:
- Baseline physical function is a critical factor influencing decisions regarding TKA for knee osteoarthritis.
- Further research is warranted to investigate whether interventions aimed at improving physical function can decrease the incidence of TKA.
