Medial Column Soft Tissue Imbrication with Internal brace Augmentation Following Lateral Column Lengthening in the Ambulatory Pediatric CP with Pes Planovalgus Foot Deformities: A Novel Indication

Abstract

Category: Midfoot/Forefoot; Other Introduction/Purpose: Pes planovalgus foot deformity is common in children with cerebral palsy (CP), and with failed bracing or painful progression, surgery is often needed. This study examines the effect of flatfoot reconstruction utilizing a novel approach to address the redundant medial soft tissue on these measures when compared to matched cohort undergoing the traditionally described soft tissue plication (STP) (Figure 1). Methods: An IRB approved, retrospective review of ambulatory pediatric CP, GMFCS I-III, patients with pes planovalgus foot deformities was conducted. Patients underwent a lateral column lengthening (LCL) along with medial column STP, with/without internal brace (IB) augmentation at a single tertiary institution by the same surgeon from 2017 to 2020. Patients were divided into two groups: without IB, and with IB augmentation. Radiographic indices on orthogonal weightbearing (WB) x-rays were measured at multiple timepoints: Preoperative, immediate postoperative and at the 3/6/12/24 months postoperative follow-up periods. Variables measured included AP and lateral talus-first metatarsal angles (TFMA), talonavicular coverage angle (TCA) and calcaneal pitch (CP). Means and standard deviation for continuous radiographic variables were calculated, followed by one-sided t-tests to compare the values between the two groups at all intervals. Results: 58 patients were identified, 31 without IB and 27 with IB augmentation. Both groups were well matched with respect to age, CP type, GMFCS level and gender. Preoperative WB radiographs showed no statistical difference between the two groups: Mean AP TFMA (26° vs. 28°, p=0.073), lateral TFMA (27° vs. 30°, p=0.067), TCA (34° vs. 30°, p=0.059) and CP (4° vs. 2°, p=0.069)(Table 1). Both cohorts maintained improved radiographic indices at the final 2-year timepoint. However, radiographs showed that the IB group had less midfoot collapse, maintaining a statistically significant difference in all radiographic parameters at final 2-year follow-up: Mean AP TFMA (13° vs. 5°, p< 0.001), lateral TFMA (11° vs. 2°,p < 0.001), TCA (15° vs. 6°,p < 0.001) and CP (10° vs. 19°,p < 0.001) Table 2). Conclusion: Internal brace augmentation is an innovative surgical technique that provides additional stability to the medial column soft tissues following LCL. This procedure will help prevent mid-foot collapse and better maintain long-term foot shape when WB. Utilizing this novel technique helps maintain proper biomechanical orientation of foot following reconstruction of pes planovalgus deformities in the ambulatory pediatric CP population.