The Effect of Agilium Freestep Ankle–Foot Orthosis on the Kinetic and Kinematic Parameters of Gait in Patients With Knee Osteoarthritis Publisher Pubmed



Boroujeni MK ; Karimi MT ; Rafiaei M ; Aghdam HA
Source: Knee Published:2026

Abstract

Background: There are several orthotic treatment options for knee osteoarthritis. Ankle–foot orthosis (AFO) is a new approach in this regard; it is designed to reduce knee joint loading and consequently reduce the joint cartilage degeneration process. Previous studies considered the knee adduction moment as a surrogate marker for knee joint loading and knee joint contact force was not measured precisely. Moreover, the effect of this orthosis on joint kinematic and ground reaction force was not evaluated in previous studies. Thus, the aim of this study was to evaluate the gait kinetic parameters including joint moment and joint contact force and kinematic parameters of patients with medial knee compartment osteoarthritis using AFO. Methods: Ten women with knee osteoarthritis participated in this study. Patients were assessed in two conditions: walking with and without AFO (Agilium Freestep®, Ottobock, Duderstadt, Germany). Thirty-six reflective markers were attached on lower limb anatomical landmarks of patients and a motion analysis system and a Kistler force plate were used to monitor the markers’ motion and collect the forces applied on the legs, respectively. OpenSim software was used to measure knee joint kinematic, moments and estimate knee joint contact force. Results: The current study showed that immediately after wearing AFO, stride length significantly decreased (1.141 ± 0.103 vs. 1.101 ± 0.095 m, P = 0.02). Moreover, the second peak of vertical ground reaction force decreased significantly (1.034 ± 0.035 vs. 1.013 ± 0.030, P = 0.02). Immediately after wearing the AFO, no statistically significant changes were observed in the knee joint contact force components or in the ankle and knee ranges of motion. Conclusion: No statistically significant difference was observed immediately after wearing Agilium AFO regarding its effect on reducing knee joint contact force and sagittal knee moment. It is important to note that due to the small sample size and the short-term nature of this study, the generalizability of these findings is limited. Further research with larger cohorts and longer follow up periods is recommended to clarify and confirm these preliminary findings. However, therapists could consider recommending this AFO for osteoarthritic knee patients to potentially decrease knee joint loading, especially for those who cannot tolerate knee orthoses. © 2026