Painful exercise for people with knee osteoarthritis: a randomised controlled feasibility trial.

Purpose: Determine the feasibility of painful exercise for people with knee osteoarthritis (KOA) to inform a future randomised controlled trial. Materials and methods: People with KOA were randomised into painful (INT) or non-painful (CON) exercise groups. Both groups performed supervised exercise twice per week for 6 weeks and received standardised education. Feasibility was assessed using participant recruitment and retention rates as well as exercise adherence and compliance. Secondary outcomes included pain, function, strength, pressure pain threshold, psychosocial measures, global impression of change, and adverse events.

Results: Twenty participants (67.4 ± 8.9 years old; 18 females) were randomised and 18 completed the study. Feasibility was supported by satisfactory rates of recruitment (INT 89%, CON 89%) and retention (INT 91%, CON 100%) as well as exercise adherence (INT 91%, CON 92%) and compliance (INT 72%, CON 81%). Outcomes improved similarly between groups, except for strength which increased more in INT compared to CON (13.0 [0.2-25.9] kg). Four participants (3 INT, 1 CON) took analgesic medication for exercise-induced pain exacerbations. No other adverse events were reported.

Conclusion: When combined with education, painful exercise is feasible for KOA. Future research comparing the effectiveness and safety of painful exercise in KOA is warranted.

Registration: ACTRN12622001231730.