Effect of unilateral and bilateral use of laterally wedged insoles with arch supports on impact loading in medial knee osteoarthritis.

BACKGROUND: Increased impact loading is implicated in knee osteoarthritis development and progression.
OBJECTIVES: This study examined the impact ground reaction force (GRF) peak, its loading rate, its relative timing to stance phase timing, and walking speed during unilateral and bilateral use of laterally wedged insoles with arch supports. STUDY
DESIGN: Within-subject design.
METHODS: Thirty-three female patients with medial knee osteoarthritis were examined with (unilateral 6° and 11°, and bilateral 0°, 6°, and 11°) and without insole use.
RESULTS: Repeated measures MANOVA revealed that the impact force increased significantly in bilateral 11° versus unilateral 6° and without-insole conditions. The loading rate decreased significantly in unilateral 11° versus bilateral 6° insoles. The relative timing increased significantly in each of bilateral 6°, bilateral 11°, and unilateral 11° versus bilateral 0° insoles and in each of bilateral 11° and unilateral 11° versus without-insole condition. There were significant positive correlations between the walking speed and each of the force and loading rate. The Chi-square test revealed insignificant association between the insole condition and the presence of impact forces.
CONCLUSION: Unilateral 11° insoles are capable of reducing impact loading possibly through increasing foot pronation. Walking slowly is another possible strategy to reduce loading. CLINICAL RELEVANCE: Unilaterally applied 11° laterally wedged insoles are capable of reducing and delaying the initial impact ground reaction forces and reducing their loading rates during walking in patients with medial knee osteoarthritis, thus reducing osteoarthritis progression. Walking slowly could also be used as a strategy to reduce impact loading. © The International Society for Prosthetics and Orthotics 2015.