Biomechanical and Clinical Outcomes With Shock-Absorbing Insoles in Patients With Knee Osteoarthritis: Immediate Effects and Changes After 1 Month of Wear

Abstract Turpin KM, De Vincenzo A, Apps AM, Cooney T, MacKenzie MD, Chang R, Hunt MA. Biomechanical and clinical outcomes with shock-absorbing insoles in patients with knee osteoarthritis: immediate effects and changes after 1 month of wear. Objectives To examine the effectiveness of shock-absorbing insoles in the immediate reduction of knee joint load, as well as reductions in knee joint load, pain, and dysfunction after 1 month of wear, in individuals with knee osteoarthritis (OA). Design Pre-post design with participants exposed to 2 conditions (normal footwear, shock-absorbing insoles) with a 1-month follow-up. Setting University laboratory for testing and general community for intervention. Participants Community-dwelling individuals (N=16; 6 men, 10 women) with medial compartment knee OA. Intervention Participants were provided with sulcus length shock-absorbing insoles to be inserted into their everyday shoes. Main Outcome Measures Primary outcome measures included the peak, early stance peak, and late stance peak external knee adduction moment (KAM); the KAM impulse (positive area under the KAM curve); and peak tibial vertical acceleration. Secondary outcomes included walking pain, the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale and total score, and a timed stair climb task. Results There was a significant reduction in the late stance peak KAM with shock-absorbing insoles ( P =.03) during follow-up compared with the baseline test session. No other immediate or longitudinal significant changes ( P >.05) in the other KAM parameters or peak tibial acceleration after use of a shock-absorbing insole were observed. However, significant improvements in all measures of pain and function ( P