Biomechanical analysis in flatfoot children: Effect of two surgical treatments by bioreabsorbable screws

Introduction: Idiopatic flatfoot iscommonin children. This condition may cause symptoms and biomechanical changes on the function of the foot and lower limbs. The aim of this study was to assessment the biomechanics of feet and lower limbs in childhood flatfeet in comparison with a healthy control group. Another purpose was to investigate the functional outcomes of two different bioreabsorbable implants 2 years after these surgical corrections. Methods: Twenty subjects were enrolled in this study: a group of 10 children (11.3±1.6 yrs, 19.7±2.8 BMI) affected by bilateral symptomatic idiopathic flatfoot and a group of 10 healthy children, matched for age and BMI (. . .), as controls. They were assessed by means of gait analysis during standing, level- and tiptoe-walking. Stereophotogrammetric analysis (8-camera Vicon Motion System, UK) was performed using a combination of established protocols, for lower limb [3] and multi-segment foot [4] kinematics. Simultaneously two dynamometric platforms were used to assess ground reaction forces and joint moments, and a surface EMG system (Wave, Cometa, Milan) to detect muscular activation of main lower limb muscles. We performed the same evaluation 2 years after the surgical correction in the group of flat feet operated with two bioreabsorbable techniques, calcaneo-stop method and sinus-tarsi endoprosthesis [1,2]. Results: Hindfoot (Shank-Calcaneus) eversion was found significantly larger in children with flatfeet in comparison to healthy subjects (Fig. 1). The forefoot was more supinated relative to the hindfoot (Calcaneus-Metatarsus inversion) in the flatfoot group. This pathological group also revealed an increase in abduction at the knee, and internal rotations at the lower limb joints with respect to the control. After surgery, the kinematic variables revealed functional improvements. In particular, a reduction of hindfoot eversion (left columns) and a reduction of inversion between metatarsus and calcaneus (right columns). Discussion: The combined lower limb and multi-segment foot kinematic analyses were found adequate to provide accurate functional assessment in young patients with flatfoot. Large foot pronation was observed before surgery. Both surgical treatments showed improvements in kinematics of the foot segments and of the lower limb joints, associated also to a more physiologic muscular activation. Reference [1] Giannini S, et al. J Bone Joint Surg Am 2001;83-A(Suppl. 2 Pt 2):73–9. [2] Roth S, et al. Foot Ankle Int 2007;28(9):991–5. [3] Leardini A, et al. Gait Posture 2007;26(4):560–71. [4] Leardini A, et al. Gait Posture 2007;25(3):453–62.