Abstract
Objective
In uncontrolled studies, a lateral‐wedge insole has reduced knee pain in patients with medial knee osteoarthritis (OA). The aim of this study was to test the efficacy of this simple, low‐cost intervention for pain in patients with medial knee OA.
Methods
We conducted a double‐blind, randomized, crossover trial designed to detect a small effect of treatment. Participants were at least 50 years of age and had medial joint space narrowing on posteroanterior semiflexed radiographs and scores indicating moderate pain for 2 of the 5 items on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale. Participants were randomized to receive a 5° lateral‐wedge insole or a neutral insole for 6 weeks. Following a 4‐week washout period, participants crossed over to the other treatment for 6 weeks. Knee pain, the primary outcome, was assessed by the WOMAC pain scale (visual analog scale version). Secondary outcomes included the WOMAC disability subscale, overall knee pain, 50‐feet walk time, chair‐stand time, and use of medications for knee pain.
Results
Ninety patients were randomized. The mean difference in pain between the 2 treatments was 13.8 points on the WOMAC pain scale (95% confidence interval −3.9, 31.4 [P = 0.13]). We observed similar small effects for the secondary outcomes.
Conclusion
The effect of treatment with a lateral‐wedge insole for knee OA was neither statistically significant nor clinically important.