Renata La Rocca Vieira MD, Abstract Co-Author: Nothing to Disclose

Zehava Sadka Rosenberg MD, Presenter: Nothing to Disclose

Valerie Peck MD, Abstract Co-Author: Nothing to Disclose

Mary Allison, Abstract Co-Author: Nothing to Disclose

Shelly Im MD, Abstract Co-Author: Nothing to Disclose

Progression of an incomplete atypical femoral fracture (IF) to a complete fracture in patients on long term bisphosphonate (BISPH) therapy can be catastrophic. Our aims were to determine the frequency and imaging features of IF in asymptomatic patients on long-term BISPH therapy and to identify distinguishing clinical and laboratory markers in the subset of patients who develop these fractures

200 femoral radiographs in 100 asymptomatic patients (93 females, 7 male, age range 57-70, mean 62.8) were prospectively reviewed by 2 radiologists. All patients were on BISPH therapy for at least 3 years and had no history of hip/thigh pain or recent trauma. MRI studies were performed when a fracture was suspected on radiographs. Bone mineral density (BMD), serum calcium, albumin, 25-hydroxy vitamin D, intact parathyroid hormone, serum c telopeptide and urine n telopeptide were obtained in all patients

2 of 100 patients (2%) had 3 IF (bilateral fractures in 1 patient). Both patients, age 50 and 57 respectively, were Caucasian, active and on BISPH therapy for 8 years. The patient with bilateral fractures demonstrated typical features of bisphosphonate-related IF: Bilateral focal, lateral cortical thickening with left incomplete transverse fracture line and no right fracture line. Lumbar spine and femoral neck BMD T-scores were -2.5 and -1.7 respectively. Laboratory data were normal. In the 2nd patient the radiographs were less typical demonstrating linear, intramedulary, subtrochanteric sclerosis. Lumbar spine and right femoral neck BMD T-scores were -1.4 and -2.7 respectively. Laboratory data demonstrated decreased bone turnover. MRI confirmed the radiographic findings in both patients. The 2 patients with IF were significantly younger (p=0.0286) than those without IF. There were no significant differences in other clinical or laboratory data (p>0.15) between the 2 groups

The 2% frequency of IF fractures in asymptomatic patients on long term BISPH therapy is higher than suggested in the literature. Aside from age, there were no significant differences in clinical or laboratory data between the 2 groups

Early detection of BISPH related IF may require screening radiographs. Larger studies are necessary to validate our findings and identify other discerning clinical and laboratory markers

Vieira, R, Rosenberg, Z, Peck, V, Allison, M, Im, S, Are Screening Radiographs Necessary to Detect Incomplete Atypical Femoral Fractures in Asymptomatic Patients on Long-term Bisphosphonate Therapy?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11004971.html