Effects of Medial Thrust Gait on Lower Extremity Kinetics in Patients with Knee Osteoarthritis

Medial thrust (MT) gait is a nonsurgical approach for reducing the knee adduction moment (KAM) in patients with knee osteoarthritis. However, its usefulness is indeterminate due to scarcity of research about changes in lower extremity kinetics and the ground reaction force (GRF) which have been investigated in this study.

Twenty patients (6 males, 14 females, age: 56.2±6.2 years) with medial knee osteo-arthritis participated in this cross-sectional study. A 12-camera motion analysis system and two force plates recorded kinematic and GRF data while participants walked barefoot along a 12m path with 1) their regular gait pattern and 2) MT gait pattern. The first peak adduction and flexion moments of the hip, knee, and ankle, and the sagittal and frontal GRF were measured. The center of pressure (CoP) location in the mediolateral direction at first KAM peak was also determined.

MT gait significantly reduced the first KAM peak (mean difference= 169.7, p<0.001) and the hip flexion moment (mean difference: 82.6, p= 0.020) compared to normal gait. The mediolateral CoP significantly shifted laterally during MT gait compared to normal gait (mean difference: -12% foot width, p<0.001). There was no significant difference in other kinetics variables between the two gait patterns (p>0.05).

1. Our findings show that MT gait can reduce the KAM with no significant increase in the GRF and other lower extremity moments. 2. The results suggest that the reduced KAM associated with MT gait is caused by a lateral shift of the CoP, resulting in a reduced GRF moment arm.