A Novel Technique for Single-stage Correction of Severe Shepherd Crook Deformity of a Femur With the Large Cystic Lesion and Pathologic Fracture

Abstract

Fibrous dysplasia with severe proximal femur deformity and multiple large cystic lesions associated with a pathologic fracture is an orthopedic challenge. Correction is often impossible with conventional fixation methods. We report a technique to address the deformity and fracture simultaneously in these scenarios. A 32-year-old man, a case of polyostotic fibrous dysplasia with severe shepherd crook deformity and the pathologic fracture was managed by curettage, multilevel osteotomy, tibial strut allograft, extramedullary fixed-angle implant, and augmentation with cortico-cancellous bone grafting in a single stage. The mechanical axis of the femur was corrected, with an increase in the neck-shaft angle from 70.6 to 121 degrees. Union was achieved with good outcomes in cosmetic and functional status without recurrence at 18 months follow-up. In proximal femur fibrous dysplasia, critical analysis of the bone stock for implant purchase especially in the proximal femur with large cystic lesions is essential. Augmentation of the head, neck, and calcar region with cortical strut allograft provide stable fixation and decreases the deformity recurrence. This technique is particularly useful in severe forms of the disease; wherein there would be an impaired implant purchase in the weak pathologic bone, deficient lateral wall, and a wide medullary canal.