Prevalence of similar or worse symptom and osteoarthritis severity of index and contralateral knees prior to knee arthroplasty: A cross-sectional multicenter cohort study

Patients considering knee arthroplasty (KA) and consulting orthopedic surgeons use different criteria to judge surgical appropriateness with surgeons placing high priority on osteoarthritis (OA) severity and age while patients place greatest emphasis on pain severity. In the face of fluctuating symptoms and high rates of bilateral knee OA, selection of the optimal knee for KA surgery can be challenging. This study examined osteoarthritis and symptom severity profiles of index versus contralateral knees of persons preparing for KA.

The nine-year Osteoarthritis Initiative data from 427 participants and five-year Multicenter Osteoarthritis Study data from 377 participants undergoing KA were included. The Western Ontario and McMaster Universities Osteoarthritis Index Pain, Function, and Stiffness Scales for both knees and radiographic readings were obtained at the visit prior to knee arthroplasty. Radar plots illustrated symptom and OA severity. Prevalence estimates of the proportion of contralateral knees with comparable or worse symptoms and OA severity relative to the index knee were reported.

The prevalence of comparable or worse knee OA on the contralateral knees as compared with index knees is 26% (95% CI = 22%, 30%). Prevalence of the same or worse WOMAC Pain for the contralateral knees relative to the index knees is 17% (95% CI = 14%, 21%).

The prevalence of comparable/worse knee OA or symptoms on the contralateral knees relative to index knees of persons undergoing unilateral KA is substantial. Methods for selecting the surgical knee should be reconsidered for this substantial subgroup of patients.