Varus knee alignment is a risk factor for medial knee osteoarthritis and is associated with high knee adduction moments. Therefore, reducing the knee adduction moment in varus-aligned individuals with otherwise healthy knees may reduce their risk for developing osteoarthritis. A gait modification that improves dynamic knee alignment may reduce the adduction moment, and systematic training may lead to more natural-feeling and less effortful execution of this pattern. To test these hypotheses, eight healthy, varus-aligned individuals underwent a gait modification protocol. Real-time feedback of dynamic knee alignment was provided over eight training sessions, using a fading paradigm. Natural and modified gait were assessed post-training and after 1 month, and compared to pre-training natural gait. The knee adduction moment, as well as hip adduction, hip internal rotation and knee adduction angles were evaluated. At each training session, subjects rated how effortful and natural-feeling the modified pattern was to execute. Posttraining, the modified pattern demonstrated an 8° increase in hip internal rotation and 3° increase in hip adduction. Knee adduction decreased 2°, and the knee adduction moment decreased 19%. Natural gait did not differ between the three visits, nor did the modified gait pattern between the post-training and 1 month visits. The modified pattern felt more natural and required less effort after training. Based on these results, gait retraining to improve dynamic knee alignment resulted in significant reductions in the knee adduction moment, primarily though hip internal rotation. Further, systematic training led to more natural-feeling and less effortful execution of the gait pattern.

Participants with lateral knee osteoarthritis exhibited frontal-plane gait mechanics at the knee and rear foot that were different from those of participants with medial knee osteoarthritis. The results of this study may guide the development of interventions specific to treating people with lateral knee osteoarthritis.

The purpose of this study was to examine the effects of laterally wedged foot orthotic devices, used to treat knee osteoarthritis, on frontal plane mechanics at the rearfoot and hip during walking. Thirty individuals with diagnosed medial knee osteoarthritis were recruited for this study. Three dimensional kinematics and kinetics were recorded as the subjects walked in the laboratory at an intentional walking speed. Peak eversion, eversion excursion and peak eversion moment were increased while the peak knee adduction moment was reduced in the laterally wedged orthotic condition compared to the no wedge condition. In contrast, no changes were observed in the variables of interest at the hip. There was no significant relationship between the change in the peak frontal plane moment at the rearfoot and change in the peak frontal plane moment at the knee or hip as a result of the lateral wedge. Laterally wedged foot orthotic devices, used to treat knee osteoarthritis, do not influence hip mechanics. However, they do result in increased rearfoot eversion and inversion moment. Therefore, a full medical screen of the foot should occur before laterally wedged foot orthotic devices are prescribed as a treatment for knee osteoarthritis.

Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS.