Are outcomes from an exercise therapy and patient education program for osteoarthritis associated with hip and knee replacement within two years? A register-based study of 9,339 patients with osteoarthritis

OBJECTIVE: The objective of this study was to determine whether short-term outcomes from exercise therapy and patient education for osteoarthritis (OA) are associated with hip or knee replacement within two years.

METHODS: Individual-level data from the Good Life with osteoArthritis in Denmark (GLA:D) Registry were linked to the Danish National Patient Registry and other national registries. Cox proportional hazards models were used to investigate associations between program outcomes (baseline to three-month changes) and time to primary hip or knee replacement. Patients who did not receive joint replacement were censored at two years, time of death, or emigration.

RESULTS: A total of 2,304 and 7,035 patients with clinically diagnosed hip and knee OA, respectively, were included. Of these, 30% with hip OA and 10% with knee OA had joint replacement within two years. Postprogram improvements in hip-related quality of life and arthritis self-efficacy (pain subscale) were associated with a reduced hazard of hip replacement (adjusted hazard ratios [HRs] for a 10-unit improvement: 0.74 [95% confidence interval (CI) 0.69-0.80] and 0.90 [95% CI 0.85-0.96], respectively). Improvements in knee pain, knee-related quality of life, and arthritis self-efficacy (pain subscale) were associated with a lower hazard of knee replacement (adjusted HRs for 10-unit improvement: 0.81 [95% CI 0.76-0.86] to 0.90 [95% CI 0.86-0.95], 0.70 [95% CI 0.63-0.78] to 0.79 [95% CI 0.72-0.86], and 0.89 [95% CI 0.83-0.94], respectively).

CONCLUSION: The magnitude of improvement in key measures after exercise therapy and education was significantly associated with the likelihood of surgery. Progression to hip replacement was three times higher than progression to knee replacement. This information can guide patient-clinician conversations around anticipated program outcomes.