LIVERPOOL, ENGLAND – Lateral wedge insoles reduced osteoarthritis knee pain to a greater extent than did wearing neutral insoles in a randomized, controlled, crossover trial.
An overall significant treatment difference of 0.7 points on a 0-10 numerical rating scale global pain score was observed when patients with painful medial osteoarthritis (OA) wore lateral wedge insoles compared with when they wore neutral insoles in their own shoes (95% confidence interval [CI], 0.1-1.2 points; P = .02).
The study’s findings are in contrast to previous research that has found no benefit of lateral wedge insoles in patients with medial compartment knee OA (JAMA. 2013;310[7]:722-30) because patients were specifically prescreened to find those who would be biomechanical responders, David T. Felson, MD, said at the World Congress on Osteoarthritis.
“There is increased medial load in medial knee OA, and that is thought to cause pain and medial joint damage,” Dr. Felson, of Boston University, said at the congress, sponsored by the Osteoarthritis Research Society International.
There is evidence, however, that by moving the center of pressure laterally during walking with the use of lateral wedge insoles, the external knee adduction movement (KAM) can be reduced by around 5%-6%, which in turn can reduce the load across the medial component.
“We asked the following question: ‘If patients were screened to remove those with painful patellofemoral OA and those who did not show a biomechanical response to lateral wedge insoles, would lateral wedge insoles actually reduce pain?’ ” Dr. Felson noted.
Sara Freeman/MDedge News
Dr. David T. Felson
For inclusion in the trial, patients needed to be aged between 40 and 80 years and have x-rays showing Kellgren-Lawrence grade 2-4 OA with definite medial and no lateral joint space narrowing in the last 2 years. They then also needed to have experienced knee pain that was rated at least 4 or more on a 0-10 numerical rating scale in the last week. Patients then had to be examined by an experienced physiotherapist or have x-rays to exclude patellofemoral OA and inflammatory arthritis.