Gait biomechanics in patients with leprosy and drop foot: preoperative and postsurgical correction analysis with tendon transposition using the posterior tibialis

Abstract

Introduction: The neurological lesion involving the common peroneal nerve caused by leprosy can lead to drop foot. Surgical correction with tendon transposition can reestablish dorsiflexion and improve gait in these patients; no study using three-dimensional analysis has reported the spatiotemporal, kinematic, and dynamic parameters preoperatively and/or postoperatively. The objective is to describe the biomechanical changes in gait in patients with leprosy and unilateral drooping foot, and to demonstrate the changes after transposition of the posterior tibialis. Methods: Twelve patients with leprosy and drop foot were evaluated in the gait laboratory. A control group of 15 healthy subjects, matched for weight and height, was used. Results: The affected limb showed increased plantar flexion in the initial contact (-16.8° ± 8.3), terminal support (-29.1°± 11.5), and balance (-12.4° ± 6.2) compared to the unaffected limb (-6.6° ± 10.3; -14.6° ± 11.6; 2.4° ± 7.6) and to the control group (-5.4° ± 2.5; -18.8° ± 5.8; -1.4° ± 3.9) (p < 0.05). The second peak ground reaction force (98.6 ± 5.2% body weight), ankle moment (0.99 ± 0.33 Nm/kg) and total ankle work during stance (-0.03 ± 5.4 J/kg) were reduced in the affected limb compared to the control group ( 104.1 ± 5.5% body weight; 1.24 ± 0.4 Nm/kg; -4.58 ± 5.19J/kg; p < 0.05). An increase in gait speed was observed after surgical correction compared to the preoperative period (0.86 ± 0.2; 0.96 ± 0.2; p < 0.001). The affected limb demonstrated improvement in ankle position at initial contact (-12.8 ± 3.0; -1.5 ± 3.5), reduction in plantar flexion peak during support (-25.1 ± 7.3; -12.7 ± 5.2), and increase in mean dorsiflexion in the swing (-16.4 ± 2.0; -8.7 ± 5.1; p < 0.001). Conclusion: Patients with leprosy and drop foot presented gait changes in the affected limb. After surgical correction, improvements were observed in spatiotemporal parameters and ankle kinematics.