First peak internal knee abduction moment (KAM) has been associated with knee osteoarthritis. Gait modification including trunk lean, medial knee thrust, and toe-in gait have shown to reduce KAM. Due to heterogeneity between study designs, it remains unclear which strategy is most effective. We compared the effects of these modifications in healthy individuals to determine their effectiveness to reduce KAM, internal knee extension moment (KEM), and medial contact force (MCF).
Twenty healthy individuals volunteered for this study (26.7 ± 4.7 years, 1.75 ± 0.1 m, 73.4 ± 12.4 kg). Using real-time biofeedback, we collected 10 trials for each modification using individualized gait parameters based on participants' baseline mean and standard deviation (SD). Two sizes of each modification were tested: 1-3 SD greater (toe-in and trunk lean) or lesser (knee adduction) than baseline for the first five trials and 3-5 SD greater or lesser than baseline for the last five trials.
A significant main effect was found for KAM and KEM (p < .001). All modifications reduced KAM from baseline by at least five percent; however, only medial knee thrust and small trunk lean resulted in significant KAM reductions. Only medial knee thrust reduced KEM from baseline. MCF was unchanged.
Medial knee thrust was superior to trunk lean and toe-in modifications in reducing KAM. Subsequent increases in KEM and variation in individual responses to modification suggests that future interventions should be individualized by type and magnitude to optimize KAM reductions and avoid detrimental effects.