Management Strategy for Symptomatic Bisphosphonate-Associated Incomplete Atypical Femoral Fractures

Abstract

Long-term bisphosphonate use has often been associated with atypical femoral fractures. These fractures evolve from incomplete femoral fractures. A previous study demonstrated that the presence of a radiolucent line in an incomplete fracture can indicate a high risk of progression to complete fracture. The aim of this study is to present a management strategy for symptomatic bisphosphonate-associated incomplete atypical femoral fractures. Specific study questions include the following: (1) Is there a difference in the prognosis of these fractures based on the presence or absence of a radiolucent fracture line? (2) Can treatment with teriparatide assist in clinical/radiographic healing of these incomplete fractures? (3) Is there a characteristic biochemical profile in these patients? We retrospectively examined all femur radiographs ordered by the metabolic bone disease service at our hospital between July 1, 2006 and July 1, 2011 and identified 10 patients with a total of 14 incomplete fractures. Nine patients received bisphosphonates for a mean duration of 10 ± 5years (range, 4-17). The mean follow-up since the time of diagnosis was 20 ± 11months (range, 6-36months). Five fractures did not have a radiolucent fracture line and were treated conservatively with partial weight-bearing restrictions and pharmacologic therapy. All five of these fractures healed with conservative management. Nine fractures had a radiolucent fracture line, and only two of these were treated successfully with conservative management including teriparatide. Six of the eight patients with a radiolucent line elected for surgical prophylaxis after 3months of conservative management, whereas one patient underwent surgical prophylaxis without a trial of conservative management. Regarding the biochemical profiles, bone turnover markers for our patient cohort were in the lower quartile. Fractures without a radiolucent line appear to respond to conservative management and not require surgical prophylaxis. Teriparatide treatment may hold promise in promoting healing of these fractures.