Evaluation the immediate effect of Iranian-manufactured Agilium-type ankle–foot orthosis on gait parameters of patients with knee osteoarthritis

Background There is various treatment options for knee osteoarthritis. Ankle–foot orthosis (AFO) is an effective way to reduce knee joint loading and improve functional abilities of patients with knee osteoarthritis. We designed an economically affordable AFO based on established Free Step AFO and then evaluated its effect on kinematic and kinetic gait parameters of patients. Method We conducted a single-arm trial to assess the effect of our Iranian-manufactured Agilium-type AFO on gait parameters of patients with knee osteoarthritis, comparing it to the Agilium Free Step AFO and to not wearing an orthosis. 10 patients with mild to moderate knee osteoarthritis were enrolled to study. A motion analysis system and a Kistler force plate were used to record lower limb segments motions and forces applied on legs. OpenSim software was used to calculate knee joint contact force and knee joint moment. Results Iranian-manufactured Agilium-type AFO significantly reduced the second peak of vertical ground reaction force in compare to not wearing an orthosis (0.988 ± 0.01 N/BW vs 1.034 ± 0.03 N/BW, p = 0.028). Furthermore, wearing the Iranian-manufactured AFO significantly reduced the first peak of vertical joint contact force (4.411 ± 1.78 N/BW vs 5.983 ± 1.52 N/BW, p = 0.021) and the first peak of the sagittal knee moment (0.142 ± 0.01 Nm/BM vs 0.489 ± 0.11 Nm/BM, p = 0.029). Conclusion The results indicated that the newly designed AFO offers a beneficial reduction in knee joint loading. Given its potential to alleviate symptoms in patients with mild to moderate knee osteoarthritis and its affordability, this AFO could be a valuable treatment option, especially in low-income countries.