Tips for improving surgical outcomes
Long-term bisphosphonate use can increase the risk of atypical femur fractures (AFFs). These atypical subtrochanteric and femoral shaft fractures, although rare, can be difficult to treat.
"Atypical femur fractures are low-energy fractures that occur mainly in older females on prolonged bisphosphonate therapy," explained Kenneth A. Egol, MD, of NYU's Hospital for Joint Diseases. "Radiographically, these fractures have unique characteristics such as a medial spike with a short-oblique fracture pattern and lateral cortical thickening. This thickening may be present not only on the outer cortices but also on the inner cortices, which makes the femoral canal narrower and more brittle. In addition, these patients tend to have a varus neck-shaft angle and/or extensive lateral bowing, making it difficult to place an implant."
Speaking at a symposium on fracture healing controversies held during the 2016 Orthopaedic Trauma Association annual meeting, Dr. Egol discussed how to improve surgical outcomes in patients with AFFs.
Complete bisphosphonate-associated AFFs require surgery, according to Dr. Egol.
"The agreed-upon treatment at our institution is fixation with an antegrade reamed interlocking intramedullary (IM) nail," he said. The following steps are also recommended when managing patients with these fractures:
- Discontinue bisphosphonate therapy.
- Supplement with calcium and vitamin D.
- Consider the use of recombinant parathyroid hormone (teriparatide).
- Assess the contralateral femur.
AFFs are often bilateral, underscoring the need to evaluate the contralateral femur, noted Dr. Egol.
"Some type of lesion, such as a stress reaction or insufficiency fracture may be present, even in asymptomatic patients," he said.
If plain radiographs of the contralateral femur are normal but the patient is experiencing pain, Dr. Egol recommended a bone scan or magnetic resonance imaging to look for evidence of an insufficiency fracture. Treatment could then include prophylactic IM nail fixation or protected weightbearing (eg, a cane or crutches), with or without the use of teriparatide. "However, if the contralateral femur looks normal on X-ray and the patient does not have pain, only follow-up observation is required; no intervention is indicated," he said.
With respect to outcomes of surgically treated AFFs, Dr. Egol cited a study by his group that evaluated 41 complete bisphosphonate-associated AFFs treated with IM nails between 2004 and 2011 at a single institution. At 1-year follow-up, 98 percent of the fractures had healed with good clinical results. "However, we noticed that these fractures take twice as long to heal as typical femur fractures," he said.
In another study, the group compared surgical versus nonsurgical treatment in 43 incomplete bisphosphonate-associated AFFs. "All of the patients in the surgical cohort (n = 21) had radiographic healing at a mean of 7 months; however, only two-thirds of them had returned to their baseline function. In the nonsurgical cohort, only 15 percent showed radiographic healing at an average of 11 months," said Dr. Egol.
In summary, Dr. Egol recommended surgical fixation with IM nails for complete AFFs. "Reduction cannot be overlooked; if you need to open it, do so. Keep in mind that these fractures take longer to heal." He also recommended surgical treatment for incomplete AFFs that are visible on X-ray or in patients who are symptomatic, but cautions that femoral geometry may influence the choice of implant.
Additional presenters during "Fracture Healing Controversies: The Problems and Solutions You Need to Know About in 2016!" were Paul Tornetta III, MD; Emil H. Schemitsch, MD; Michael McKee, MD; Aaron Nauth, MD; and Gerard P. Slobogean, MD.
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Maureen Leahy is the assistant managing editor of AAOS Now. She can be reached at email@example.com
- Bisphosphonate-associated AFFs can be difficult to manage.
- Discontinuation of bisphosphonates, supplementation with calcium and vitamin D, and use of teriparatide should be considered in patients with these fractures.
- Evaluation of the contralateral femur for evidence of a stress fracture is also important.
- Surgical fixation with IM nails is recommended for all complete bisphosphonate-associated AFFs.
- Surgical fixation should also be considered for incomplete fractures that are radiographically visible or when the patient is symptomatic.