CORA-Based Single-Stage Double-Level Corrective Osteotomy for Pediatric Distal Tibiofibular Malunion with Multiplanar Valgus Ankle Deformity: A Case Report

Abstract

Introduction. Distal tibiofibular malunion in the skeletally immature patient can generate a progressive multiplanar valgus ankle deformity that alters joint mechanics and threatens long-term function. Correction is especially demanding after neglected, non-medical treatment, which remains common in low- and middle-income settings.

Case Presentation. A 13-year-old boy presented with a one-year history of progressive valgus deformity of the right ankle following a road-traffic injury initially managed by a traditional bone setter without radiographs. Imaging confirmed distal tibiofibular malunion with center of rotation of angulation (CORA) values of 16.9° in the coronal plane and 18.1° in the sagittal plane; the tibial anterior surface (TAS) angle was 76.4° and the tibial lateral surface (TLS) angle was 76.0°. A single-stage, CORA-based double-level closing-wedge osteotomy of the distal fibula and distal tibia was performed, stabilized with a one-third tubular plate and a distal tibial T-locking plate. The TAS improved to 93.0° and the TLS to 84.0°. At one-year follow-up the patient showed bony union, improved ankle motion, restored mechanical alignment, and painless ambulation without complications.

Conclusion. CORA-guided single-stage double-level osteotomy with stable internal fixation can restore alignment, ankle congruity, and function in pediatric distal tibiofibular malunion with multiplanar valgus deformity. Early orthopedic evaluation and timely correction are essential to prevent long-term disability.