A Gait Modification to Reduce the External Adduction Moment at the Knee: a Case Study

Knee osteoarthritis (OA) is the most common form of arthritis, and affects approximately one-third of the elderly population. The medial tibiofemoral compartment is most commonly involved. This is due, in part, to the ground reaction force vector passing medial to the knee joint center during gait. This distance increases with genu varus malalignment, resulting in an increased external adduction moment at the knee (KEAM). A high KEAM has been previously associated with medial tibiofemoral OA disease progression and severity (Mundermann, et al., 2004, Miyazaki, et al., 2002). Reduction of the KEAM has been reported after high tibial osteotomy, and to a lesser extent with the use of conservative measures such as wedged orthoses (Prodromos, et al., 1985, Kerrigan, et al., 2002). In an asymptomatic, varus-aligned population without diagnosed knee OA, reducing the KEAM may serve to delay or prevent the onset of the disease.