Simulation of Tendon Transfer Surgery

A biomechanical model is used to simulate a tendon transfer operation. The model predicts the required forces in twelve ankle muscles during standing and walking, and also the endurance time of the (instantaneous) posture. In particular, the mechanical effect of anterior transfer of the posterior tibial tendon of a patient with muscle paralysis due to peroneal nerve injury is studied. The results show that before surgery the patient can stand normally but cannot walk normally. Normal walking is mechanically not possible because the required muscle forces in early stance cannot be produced, although the necessary forces can be realized during the remainder of stance. After surgery, both normal standing and normal walking are mechanically possible. The cost is higher forces and shorter endurance times in the healthy muscles. The results agree with clinical findings.