The effect of triple arthrodesis on soleus and peroneus brevis muscles, and on knee flexion/extension during gait

We studied the effects of bilateral triple arthrodesis (BTA) on the strength of soleus and peroneus brevis muscles, and on knee flexion/extension during gait using EMG and a kinematic model of the lower limb. We found that the maximum knee flexion and extension was reduced in all patients compared to the average value of normal subjects. Moreover, the peroneus brevis was more active in the early stance phase and soleus EMG patterns were abnormal in early stance, absent in late stance, but became active at pre-swing in patients, patterns that differed from normal subjects.