RESEARCH - Bilateral low-energy simultaneous or sequential femoral fractures in patients on long-term Fosamax therapy

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J Bone Joint Surg Am. 2009 Nov;91(11):2556-61.

Bilateral low-energy simultaneous or sequential femoral fractures in

patients on long-term alendronate therapy.

Capeci CM, Tejwani NC.

Department of Orthopaedic Surgery, New York University Hospital for

Joint Diseases, 301 East 17th Street, Suite 1401, New York, NY 10003,

USA.

BACKGROUND: While alendronate therapy has been shown to decrease the

risk of vertebral and femoral neck fractures in postmenopausal

osteoporotic patients, recent reports have associated long-term

alendronate therapy with unilateral low-energy subtrochanteric and

diaphyseal femoral fractures in a small number of patients. To our

knowledge, there has been only one report of sequential bilateral

femoral fractures in patients on long-term bisphosphonate therapy.

METHODS: We retrospectively reviewed the case log of the senior author

over the last four years to identify patients who presented with a

subtrochanteric or diaphyseal femoral fracture after a low-energy

mechanism of injury (a fall from standing height or less) and who had

been taking alendronate for more than five years. Radiographs were

reviewed, and the fracture patterns were recorded. Serum calcium

levels were recorded when available.

RESULTS: Seven patients who sustained low-energy bilateral

subtrochanteric or diaphyseal femoral fractures while on long-term

alendronate therapy were identified. One patient presented with

simultaneous bilateral diaphyseal fractures, two patients had

sequential subtrochanteric fractures, and four patients had impending

contralateral subtrochanteric stress fractures noted at the time of

the initial fracture. Of the latter four, one patient had a fracture

through the stress site and the other three patients had prophylactic

stabilization of the site with internal fixation. No patient had

discontinued alendronate therapy prior to the second fracture. All

patients were women with an average age of sixty-one years, and they

had been on alendronate therapy for an average of 8.6 years. All

fractures were treated with reamed intramedullary nailing and went on

to union at an average of four months.

CONCLUSIONS: In patients on long-term alendronate therapy who present

with a subtrochanteric or diaphyseal femoral fracture, we recommend

radiographs of the contralateral femur and consideration of

discontinuing alendronate in consultation with an endocrinologist. If

a contralateral stress fracture is found, prophylactic fixation should

be considered.

PMID: 19884427

http://www.ncbi.nlm.nih.gov/pubmed/19884427

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