[Feet insoles and knee osteoarthritis: evaluation of biomechanical and clinical effects from a literature review].

Objective: To determine the biomechanical and clinical effectiveness of foot insoles in patients with knee osteoarthritis.
Materials and Methods: A systematic review of the literature (Medline, Pascal and Embase) using the MESH words knee, and insole and plantar orthosis for the biomechanical part and osteoarthritis, and insole and plantar orthosis for the clinical part. Clinical studies were classified by 2 independent readers using the Jadad scale.
Results: Two biomechanical theories were found: the adduction moment theory, which explains the effect of heel wedging, and articular chain theory, which explains the effect of lateral wedged insoles. The clinical effect was explained more by an anti-algesic effect than an anatomic or functional effect: the treated group consumed fewer nonsteroidal anti-inflammatory drugs than the placebo group for up to 2-years of treatment. Evidence is lacking because of methodological weakness and few clinical trials. The information on side effects is limited.
Discussion: Laterally wedged foot insoles are proposed for the treatment of knee medial compartment osteoarthritis. The clinical effect is probably limited, but the treatment may reduce the digestive and renal side effects of prolonged use of nonsteroidal anti-inflammatory drugs. Foot insoles could be recommended in clinical practice despite the lack of evidence in comparing the effectiveness of other therapeutics in knee osteoarthritis.
Conclusion: Use of foot insoles is a nonpharmacologic treatment of osteoarthritis of the knee medial compartment.