OTA 2011 Posters

Scientific Poster #56 Geriatric Fractures OTA-2011

Is Bisphosphonate Usage Associated With Atypical Humeral Diaphyseal Fractures?

Matthew A. Popa, MD1; Clifford B. Jones, MD, FACS2,3; Debra L. Sietsema, PhD2,3;
Shaun Kink, BS3; Matthew S. Nies, BS3;
1Grand Rapids Orthopaedic Residency Program, Grand Rapids, Michigan, USA; 2Orthopaedic Associates of Michigan, Grand Rapids, Michigan, USA; 3Michigan State University, Grand Rapids, Michigan, USA

Purpose: A number of recent case series and retrospective reviews have identified a subgroup of atypical fractures of the femoral shaft associated with bisphosphonate use. These case series have suggested that long-term bisphosphonate use may ultimately alter bone strength, most likely due to suppression of bone turnover. In addition to subtrochanteric femur fractures, we have noted atypical humerus fractures in association with low-energy falls and bisphosphonate usage. Thus far the literature is sparse with regard to the possible association of long-term bisphosphonate use with atypical fractures of the humerus.

Methods: From 2001 to 2010, 1290 consecutive patients with humeral fractures were identified in a retrospective review. Patient charts and fracture images were reviewed. Demographic data of gender, age, history of bisphosphonate usage, length of bisphosphonate usage, mechanism of injury, fracture pattern (OTA/AO classification), and fracture treatment were obtained. Patients who sustained fractures while on bisphosphonates were identified. Patients were assigned into 2 groups, one with bisphosphonate usage prior to the fracture and one with no history of bisphosphonate usage. From this group, we identified and analyzed a subgroup of patients with atypical diaphyseal humeral fractures with a low-energy mechanism of injury (defined as a fall from standing height or less).

Results: A total of 89 humeral fractures were identified in patients with current or prior bisphosphonate usage. 14 of 89 (16%) of these fractures were diaphyseal and 75 (84%) were proximal metaphyseal humeral fractures. Of the diaphyseal fractures, 12 were associated with a low-energy mechanism of injury. These included 10 females and 2 males with a mean age of 73 years (range, 50-89 years). The “atypical” diaphyseal humeral patterns were transverse or short oblique with cortical thickening (type I), lateral bending wedge (type II), and severely comminuted (type III). Patients with these “atypical” fracture patterns had bisphosphonate usage for an average of 4.9 years (range, 0.3-12 years), which was significantly longer (P = 0.03) compared to 1.3 years (range, 0.1-4.5 years) of bisphosphonate usage for those without these fracture patterns. Additionally, we noted that worsening atypical fracture pattern type related to duration of bisphosphonate usage.

Conclusion: Multiple case series have demonstrated that bisphosphonate usage is associated with atypical subtrochanteric femoral fractures. This is the first report to associate atypical diaphyseal humeral fractures with bisphosphonate usage. Additionally we recommend a classification scheme. Further analysis and prospective studies to more fully delineate the association between bisphosphonate usage and atypical fractures in the humerus and other parts of the skeleton are recommended.

• The FDA has not cleared this drug and/or medical device for the use described in this presentation   (i.e., the drug or medical device is being discussed for an “off label” use).  ◆FDA information not available at time of printing. Δ OTA Grant.