Bisphosphonate-associated fractures of the proximal femur require greater treatment vigilance

Proximal femur fractures in patients with a history of bisphosphonate therapy are difficult to treat and heal, according to Jaimo Ahn, MD, PhD. As a result, these fractures require vigilance, including careful preoperative planning, follow-up, and patient counseling.

“Bisphosphonates have been successful in improving patient outcomes at the epidemiologic level; however, long-term bisphosphonate use may decrease bone turnover, which results in brittleness. This can lead to intramedullary (IM) nailing complications such as iatrogenic injuries and comminution of the fracture. Even with the use of biologics, patients still have a difficult time healing,” Dr. Ahn explained.

Identifying the cohorts
Dr. Ahn and his fellow researchers conducted a retrospective, single-surgeon review comparing pre-, intra-, and postoperative data of female patients older than age 50 with fractures of the femur treated between 2002 and 2008. The bisphosphonate cohort (BC) consisted of 25 patients (average age: 71 years; average duration of bisphosphonate therapy: 7.6 years) with subtrochanteric to middle-third femur fractures of low-energy mechanism.

The control cohort (CC) consisted of 20 patients (average age: 74 years) with similar preoperative demographics, but with no history of bisphosphonate therapy. The data did suggest a greater prevalence of patient-reported osteoporosis in the BC, but the difference was not statistically significant, noted Dr. Ahn.

Comparing the data
In comparing the perioperative data between the two groups, the researchers found a significantly higher overall complication rate (p < 0.0001) for the BC compared to the CC. Intraoperative fractures and postoperative plate failures and nonunions were the most notable complications (Table 1). In addition, the healing time for the BC was delayed compared to the CC (26 weeks versus 19 weeks, p = 0.01).

“Strikingly, BC patients showed cortical thickening, where the cortex was a much greater proportion of the shaft than in CC patients,” said Dr. Ahn. “Many of these patients also received teriparatide treatment after metabolic evaluation and yet had a statistically significantly longer healing time.”

Orthopaedic surgeons, he says, need to be aware of the difficulties of treating proximal femur fractures in patients who have used bisphosphonates. “Due to the geometry and brittleness of the fractures, IM nailing—otherwise standard treatment—is not routine in these patients and plate constructs are prone to failure. These patients require more vigilance than the standard hip fracture patient,” said Dr. Ahn.

Dr. Ahn presented “Operative Outcomes and Treatment Difficulties for Fractures of the Proximal Femur Associated with Bisphosphonate Therapy,” at the 2010 Orthopaedic Trauma Association annual meeting. His coauthors include Mark L. Prasarn, MD; Omesh Paul, MD; Paul E. Matuszewski, MD; Joseph M. Lane, MD; and Dean G. Lorich, MD.

Disclosure information: Dr. Lane—Eli Lilly; Novartis; Sanofi-Aventis; Weber Chilcott; Amgen Co.; Biomimetic; Zimmer; DFine, Inc.; Graftys SA; Kuros Biosurgery AG; Zelo Therapeutics, Inc. All other authors reported no conflicts.

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom line

• Fractures of the proximal femur associated with bisphosphonate therapy are difficult to treat and heal.
• Treating these fractures with IM nailing can lead to iatrogenic fractures and plate constructs are prone to failure.
• Even with the use of biologic adjuvants, these fractures are difficult to heal and take a longer time to achieve union than standard hip fractures.
• Fractures of the proximal femur associated with bisphosphonate therapy require vigilance, appropriately aggressive care, and careful further study.