Case reports: subtrochanteric femoral stress fractures after prolonged alendronate therapy.
BACKGROUND
Alendronate is known for its ability to reduce bone loss in osteoporotic and osseous metastatic conditions. Its long-term effects remain unclear although several reports describe cases of proximal femur stress fractures associated with long-term alendronate use.


METHODS
We report the cases of four women who sustained low-energy subtrochanteric or femoral shaft stress fractures while being on alendronate therapy for more than 5 years. All radiographs showed typical patterns consisting of a transverse fracture line with external cortical bone reaction and medial cortical spike. Alendronate discontinuation along with nonoperative treatment was sufficient for one patient, whereas surgical stabilization was required in three patients.


METHODS
The side effects of alendronate therapy include osteonecrosis of the jaw, esophageal irritation, and musculoskeletal pain. Several cases of insufficiency femoral fractures associated with prolonged alendronate use have been reported. Their radiographic pattern and clinical presentation are consistent with our observations. Although various hypotheses have been suggested, the physiopathogenesis of these stress fractures is not completely understood.


CONCLUSIONS
Although bisphosphonates play an important role in preventing pathologic fractures in patients with cancer, these subtrochanteric stress fractures associated with prolonged use of alendronate should not be ignored.
Cermak
Katerina
K
Department of Orthopedic Surgery, Institut Jules Bordet, Université Libre de Bruxelles, 1 rue Heger-Bordet, 1000, Brussels, Belgium. katia.cermak@hotmail.com
Shumelinsky
Felix
F
Alexiou
Jean
J
Gebhart
Michael J
MJ
D000368:Aged; D019386:Alendronate / Q000009:adverse effects*; D050071:Bone Density Conservation Agents / Q000009:adverse effects*; D001858:Bone Nails; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation / Q000379:methods / Q000534:rehabilitation; D015775:Fractures, Stress / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D006801:Humans; D008875:Middle Aged; D011859:Radiography; D016896:Treatment Outcome
D050071:Bone Density Conservation Agents; D019386:Alendronate