Objective
To determine the feasibility of a full‐scale randomized controlled trial (RCT) comparing foot orthoses and footwear to footwear alone in individuals with patellofemoral (PF) osteoarthritis (OA).
Methods
This 4‐month, parallel, 2‐arm pilot trial took place in Brisbane, Queensland and Hobart, Tasmania (August 2014 to October 2016). Forty‐six individuals with PF OA were randomized by concealed allocation to foot orthoses plus prescribed footwear (n = 24) or prescribed footwear alone (n = 22). Study feasibility was the primary outcome (e.g., recruitment rate, adherence, adverse events, dropout rate). Secondary outcomes included patient‐reported outcome measures of pain, function, and quality of life. Effect sizes with 95% confidence intervals were calculated at the 4‐month primary end point (standardized mean differences for between‐group effects; standardized response mean for within‐group effects).
Results
From 782 volunteers, 47 were eligible (6%), and 46 participated. One participant withdrew (2%), and 1 (2%) was lost to follow‐up. Intervention adherence was high for both groups (9–10 hours of wear per day). No serious adverse events were reported. More than 80% of questionnaires were completed at 4 months. Between‐group effect sizes for patient‐reported outcome measures were typically small, while moderate‐to‐large within‐group response effects were observed in both groups.
Conclusion
A full‐scale RCT for PF OA is feasible with modifications to eligibility criteria. However, our observed small between‐group effect sizes, combined with moderate‐to‐large within‐group responses for both interventions, indicate that a full‐scale trial is unlikely to find clinically meaningful differences. Secondary outcomes suggest that both interventions can be recommended for individuals with PF OA.