Post-traumatic osteonecrosis of the talus

Abstract

About three of four cases of avascular necrosis (AVN) of the talus are of posttraumatic origin. Risk factors include displacement, open fractures and dislocations, patient age, high BMI and smoking. For the management of adverse sequelae of talar fractures like malunion and nonunion, the distinction between partial and total AVN with collapse of the talar dome is of great relevance.

Treatment options for precollapse AVN include protection, medication, extracorporeal shock wave therapy, bone marrow aspirate, drilling, and (vascularized) bone grafting. In the presence of partial AVN, malunions or nonunions of the talar neck and body may be treated with joint-preserving corrections in active, compliant patients, provided a sufficient vital cartilage and bone stock is present.

Complete talar AVN with collapse may be salvaged with necrectomy, bone grafting and fusion of arthritic joints. Recently, custom 3D prostheses providing either total talar replacement or talar body replacement with preservation of the talar head, have gained more attention, but long-term results are missing. Talar replacement may also be combined with ankle replacement and / or subtalar fusion.

Septic AVN of the talar body as the worst case scenario warrants staged treatment with radical debridements until negative swabs are obtained. Besides allograft and autograft bone, customized cages, trabecular metal, or biomaterials like bioglass with antiinfective properties may be used for secondary defect filling. Reconstruction and fusion is obtained with internal or external fixation. With critical soft tissue conditions, partial or total astragalectomy and tibiocalcaneal fusion may serve as a salvage procedure.