Simulation of Tibialis Anterior Muscle Transfer for Congenital Clubfoot Based on OpenSim

Congenital clubfoot is a common deformity in children with cerebral palsy. It results in child's foot inversion with horseshoe shape, which seriously affects the basic function of normal walking. For the evaluation of the effect of treatment, in addition to clinical testing, the previous study used the three-dimensional gait analysis system to verify the effect of the treatment. These evaluations can only evaluate the results after the treatment but not predict the effect of the operation. Therefore, this paper adopts OpenSim modeling software to establish a personalized human body model by manually scaling and importing the joint angle. Changes in tendon moment and moment arm before and after transfer are examined in this experiment. The maximum dorsal flexion moment of the tibialis anterior muscle is changed from 15 N · m (before transfer) to 18 N · m (after transfer), and the average moment arm is changed from 24 mm to 29 mm. The maximum inversion moment of the tibialis anterior muscle is changed from 18 N · m (before transfer) to 1 N · m (after transfer), and the average moment arm is changed from 19 mm to -3 mm, which becomes eversion moment. It can be seen the tibialis anterior muscle transfer surgery increases the dorsal flexion moment, reduces the inversion moment, and also increases the eversion moment, which has significant effects in the treatment of clubfoot. By taking these effect into consideration, we can help the doctor to determine a better surgical plan.