Muscle coactivation during gait after percutaneous repair of Achilles tendon: a case report

The muscle coactivation phenomenon (mCoA) has been used to describe motor tasks such as human gait, reflecting the levels of joint stability of the lower limbs in healthy people versus patients with musculoskeletal problems. Nonetheless, scarce literature has described the mCoA evolution in patients with Achilles tendon reconstruction surgery. The aim of this study was to describe the mCoA during human gait in one patient undergoing Achilles tendon reconstruction surgery for acute tendon rupture with a new surgical technique (PARS-Dresden) in two times-frame (12 and 24 weeks). Human gait was recorded on a treadmill at 2.5 km/h. This task was recorded with a 3D motion system synchronized with electromyographic (sEMG) equipment. The sEMG signals were acquired from three portions of the triceps surae (soleus [So], medial [MG], and lateral [LG] gastrocnemius) and tibialis anterior [TA], in both shanks. The mCoA levels (represented as a percentage) were calculated considering twenty gait cycles in muscular pairs TA-MG, TA-LG, and TA-So, in both operated (OL) and non-operated (NOL) limbs. The analysis was estimated with a processing pipeline developed in Python language, considering the Falcone and Winter equation. The results showed a slight increase in the mCoA during gait in some muscular pairs at 24 weeks. The coactivation levels were greater in the TA-MG and TA-So pairs of the OL vs the NOL. Additionally, a higher asymmetry was observed between OL vs NOL at the 12 weeks.