Allograft Deltoid Ligament Reconstruction and Z-Lengthening Fibular Osteotomy for Residual Valgus Instability After Ankle Fracture Fixation: A Case Report

Residual valgus instability following ankle fracture fixation presents a reconstructive challenge, especially when medial soft tissue compromise precludes early deltoid ligament repair. Restoring medial stability, together with fibular length and syndesmotic alignment, is crucial for re-establishing joint congruity and preventing progressive deformity or degenerative complications. In this single-patient case report, we describe a novel technique combining the use of an allograft deltoid ligament reconstruction with a Z-lengthening distal fibular osteotomy in a young adult male who developed residual valgus instability after the lateral-only fixation of a Weber C ankle fracture–dislocation. The Z-lengthening osteotomy enabled the controlled, fluoroscopy-guided restoration of fibular length and the correction of syndesmotic malreduction. Concurrently, medial stabilization was achieved with a suspensory-and-aperture fixation allograft construct, providing a tensionable anatomic reconstruction of the deltoid complex. This integrated approach restored the alignment of the medial clear space and syndesmosis, resulting in a pain-free, stable ankle mortise. At the three-year follow-up, the patient maintained a stable reduction with no radiographic signs of post-traumatic arthritis. The technique offers a reproducible, joint-preserving solution that merges mechanical correction with biological reconstruction to restore circumferential ankle stability and facilitate functional rehabilitation after complex ankle fracture fixation.