Construct Failure in an Atypical Femoral Fracture treated with Intramedullary Nailing: A Case Report

Abstract

Aims: Atypical femoral fractures (AFFs) have been reported after prolonged intake of bisphosphonates (BPs) since 2005.1 There has been a steady increase in published evidence associating BPs and AFFs, but a causal relationship has not yet been established. The updated case definition of an AFF is a fracture located along the femoral diaphysis from just distal to the lesser trochanter to just proximal to the supracondylar flare, with at least four of five major features present.2 Delayed fracture healing is a recognized minor feature in AFFs, which may or may not be present in a given case. If delayed healing or non-union does occur, literature still lacks a standardized treatment regimen.3 The aim of this paper is to document a rare case of construct failure in a 68 year old Filipina who sustained an AFF in her left subtrochanteric area. Methods: The patient previously had a 40-month history of alendronate 70 mg+vitamin D 5600 U therapy for osteoporosis. She was treated by her primary orthopedic surgeon with immediate cessation of BPs and closed intramedullary nailing. The patient was already bearing full weight and was apparently well until 6 months postoperatively, when she began to experience progressive pain in her operated thigh. There was no precipitating trauma. The patient sought consult with another orthopedic surgeon, where radiographs revealed a broken nail at the proximal screw hole and non-union of the AFF. She was treated with opening of the fracture site, removal of the broken device, exchange intramedullary nailing, and iliac bone grafting. Results: The patient then went on to heal uneventfully. She had radiographic and clinical union with full weight-bearing after 3 months. Conclusions: AFFs are now more commonly recognized by diagnosing physicians due to increasing awareness. The case presented in this paper though, shows that correct diagnosis and proper treatment according to current recommendations2 does not guarantee a good outcome. AFFs should be followed-up closely andmay need pharmacologic supplementation in order to heal.3 If delayed healing or nonunion does occur, it may be complicated further by the presence of a broken implant. An effective and consistent protocol has not yet been defined, but initial reports of cases managed successfully may help guide treatment of these difficult injuries.