The biomechanical effects of a new design of lateral wedge insole on the knee and ankle during walking.

Lateral wedged insoles are a common treatment in individuals with medial tibiofemoral osteoarthritis of the knee joint. One concern has been the potential for increased foot and ankle pain due to increased eversion. The purpose of this study was to assess the biomechanical effectiveness of a typical lateral wedged insole and a combined insole with a lateral wedge and off-the-shelf anti-pronatory device in shoes while walking. A cross-over randomized design was used where each insole was worn by fifteen healthy subjects while three-dimensional motion data were collected in three different conditions: (1) control condition (with standard shoes), (2) with an insole with a lateral wedge and additional off-the-shelf anti-pronatory support (supporting), and (3) with an insole with a lateral wedge with no additional support (unsupported) in the standard shoes. The unsupported insole significantly increased the amount of ankle/subtalar joint complex eversion than the other experimental conditions, with the supporting insole reducing the ankle/subtalar joint complex eversion, and was found to be more comfortable. Both the supporting and unsupported lateral wedged insoles significantly reduced knee loading (external knee adduction moment reduction 8.5% and 9.1%, respectively), the knee adduction angular impulse. This new design of lateral wedge may offer increased adherence in future osteoarthritis population studies while offering reductions in joint loading.