Background: 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.
Questions/purposes: 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?
Patients and methods: 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 ± 5 years (range, 4-17). The mean follow-up since the time of diagnosis was 20 ± 11 months (range, 6-36 months).
Results: 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 3 months 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.
Conclusions: 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.
Keywords: atypical femoral fractures; bisphosphonates; incomplete fractures; radiolucent fracture line; teriparatide.