Responders to first-line osteoarthritis treatment had reduced frequency of hip and knee joint replacements within 5 years: an observational register-based study of 44,311 patients.

BACKGROUND AND PURPOSE: First-line treatment (education, exercise) for patients with hip and knee osteoarthritis (OA) aims to reduce pain and improve function. We aimed to compare progression to joint replacement within 5 years between responders and non-responders to first-line treatment for hip and knee OA, respectively.

METHODS: This observational study included data for 30,524 knee OA and 13,787 hip OA patients from the Swedish Osteoarthritis Register, linked with the Swedish Arthroplasty Register, Statistics Sweden, and the Swedish Prescribed Drug Register. The primary prognostic factor was change in pain between baseline and 3-month follow-up, measured on a numeric rating scale (0-10, best to worst) where an improvement of ≥ 2 was classified as responder and ≤ 1 as non-responder. The main outcome was progression to joint replacement surgery within 5 years, assessed using baseline adjusted multivariable Cox regression analyses.

RESULTS: At 5 years, in hip OA, 35% (95% confidence interval [CI] 32.2-37.2) of the responders and 48% (CI 45.9-49.5) of the non-responders and in knee OA 14% (CI 13.0-15.3) of the responders and 20% (CI 18.8-20.8) of the non-responders had progressed to joint replacement. Being a responder to the treatment was associated with having a lower probability of progression to surgery for both hip OA (hazard ratio [HR] 0.4, CI 0.4-0.5) and knee OA (HR 0.6, CI 0.5-0.6).

CONCLUSION: Patients with hip or knee OA who experienced pain relief after a first-line OA treatment program were less likely to progress to joint replacement surgery.