Kinematic, Electromyographic Activity and Muscular Architecture Description in Patients Operated with Pars-Dresden Technique

Abstract

Category: Sports; Ankle; Basic Sciences/Biologics Introduction/Purpose: Kinematic, muscular architecture and myoelectric activity are altered during the healing process after Achilles tendon surgery. Currently, there are minimally invasive surgical techniques (PARS-Dresden) which have accelerated rehabilitation processes. However, evidence that compares kinematic, architecture and myoelectric activity between operated vs. non-operated leg is limited. The aim of this study is to describe the kinematic changes, muscular architecture and electromyographic (EMG) activity of the lower limb between operated vs. non-operated legs after Achilles tendon surgery. Methods: After obtaining IRB approval, patients undergoing the PARS-Dresden technique for acute Achilles tendon ruptures were invited to participate. We excluded patients with previous injuries or surgery in lower limbs that affect gait, muscular activity, or architecture. Eleven patients met the inclusion/exclusion criteria. Patients were evaluated at three time-frames: 8, 12, and 24 weeks. Evaluations were performed walking on a treadmill at self-selected speed, while kinematic and surface EMG activity was measured in stance and swing phases of the gait. Kinematic variables were captured using a 3D motion analysis system with eight infrared cameras and twenty reflective markers over the lower limbs. Muscle architecture was evaluated using ultrasonography. A descriptive analysis was performed comparing operated versus non-operated legs. Results: Median age 36 years, 3 females. Kinematic evaluation shows sagittal plane asymmetry between operated versus non- operated legs at 8 and 12w. However, the 24w evaluation shows symmetry between both lower limbs. The EMG shows lower activity in the stance phase for the medial gastrocnemius, lateral gastrocnemius, and soleus for operated legs at 8w and 12w, but at the 24w evaluation the activity was symmetric for these muscles evaluated in both legs. The muscular architecture shows less thickness in gastrocnemius muscles in the operated leg at 8w (median 11.2% operated vs 35.4% no-operated), reaching a symmetric thickness at 24w (median 34.2% operated vs 35.7% no-operated). Achilles tendon present asymmetric transversal area between both legs at three time-frames (median 1.88 cm 2 versus 0.59 cm 2 ). The pennation angles showed no difference between both legs in the three evaluation periods (median 22.0° versus 24.3° for MG, and 15.0° versus 13.5° for LG). Conclusion: We described kinematic, electromyographic and architectonic asymmetries between operated versus non-operated legs at 8 and 12 weeks postoperative of patients who underwent PARS-Dresden surgery for acute Achilles tendon ruptures. All patients achieved symmetric results at 24 weeks evaluation.