Effects of Varus Knee Alignment and Using Toe-cages on Frontal Plane Knee Biomechanics in Stationary Cycling

Effects of varus knee alignment on the internal knee abduction moment (KAM) in walking has been widely studied. KAM has been shown to be closely associated with the development of medial knee osteoarthritis (OA). Despite the importance of the knee alignment, no studies have explored its effects on knee frontal plane biomechanics during stationary cycling. The purpose of this study was to examine the effects of varus knee alignment and using a toe-cage on the knee frontal plane biomechanics during stationary cycling. Eleven participants in each of the varus and neutral groups participated in the study. The participants performed in six stationary cycling conditions: pedaling at 80 rpm at 0.5 kg (40 Watts), 1.0 kg (78 Watts), and 1.5 kg (117 Watts) with and without a toe-cage. A motion analysis system and a custom instrumented pedal were used to collect kinematic and kinetic data. A varus knee alignment and using toe-cage did not result in greater peak knee adduction angle and peak KAM. These findings suggest stationary cycling may be a safe exercise prescription for people with varus knee alignment, including patients with medial knee compartment OA. In addition, using toe-cage may not have any negative effects on knee joints in stationary cycling. Future studies may be needed to explore the tibiofemoral contact force in subjects with a varus knee alignment during stationary cycling.