Immediate efficacy of laterally wedged insoles with arch support on walking in persons with bilateral medial knee osteoarthritis.

ABSTRACT

OBJECTIVE: To investigate the immediate efficacy of laterally wedged insoles with arch support (LWAS) on gait in persons with bilateral medial knee osteoarthritis (OA). DESIGN: A prospective case-control intervention study. SETTING: A gait laboratory with a 6-camera motion analysis system and 2 forceplates. PARTICIPANTS: Fifteen women with bilateral medial knee OA and 15 healthy control subjects (N=30). INTERVENTIONS: LWAS. MAIN OUTCOME MEASURES: Subjective knee pain and objective biomechanical indices, namely, joint angles and moments in the frontal plane, frontal plane ground reaction force and lever arm, as well as medial/lateral center of mass and center of pressure during gait. RESULTS: When wearing the LWAS, knee pain during gait in persons with medial knee OA decreased (P=.01). Peak internal knee abductor moments were also reduced (P<.001) with increasing foot progression angles, laterally shifted center of pressure, and a shortened frontal plane lever arm (all P<.05). However, ankle invertor moments were increased (P<.05) when wearing the LWAS. CONCLUSIONS: Although peak internal knee abductor moment and knee pain were immediately reduced during gait when wearing the LWAS, increased ankle invertor moments were found, suggesting that the LWAS should be used with caution. Strengthening and monitoring the condition of the ankle invertor muscles may be necessary if the LWAS is used as an intervention for persons with bilateral medial knee OA.