Treatment status and radiographic features of patients with atypical femoral fractures

The Japanese Orthopaedic Association (JOA) has been surveying approximately 3000 orthopedic surgery hospitals and clinics with inpatient facilities nationwide to collect information on atypical femoral fractures (AFFs) and patient characteristics since 2010. The present study aims to examine radiographic images and clarify the relationship between radiographic and patient characteristics of patients with AFF and treatment status. The study involved 1996 facilities certified as clinical training sites by the JOA and 912 clinics with inpatient facilities affiliated with the Japanese Clinical Orthopaedic Association (JCOA). Additional clinical data collection and radiographic image review were performed in patients aged 35 years or older who met the American Society for Bone and Mineral Research (ASBMR) case definition for AFF and received treatment at participating facilities registered with JOA in 2013. Radiographic images were evaluated in accordance with the ASBMR case definition. Radiographic images of 304 fractures in 304 patients were collected. Among them, 230 fractures were determined to be AFFs. The fracture site was the proximal third in 70 AFFs (30.4%), middle third in 157 AFFs (68.3%), and distal third in 3 AFFs (1.3%). Among patients with AFFs, 173 (75.2%) were treated with bisphosphonates (BPs) and 45 patients (19.6%) were not (unknown in 12 patients). Duration of use was three years or longer in 103 patients (59.5%) and between one and three years in 24 patients (13.9%). Radiographic beaking was observed in 149 fractures (86.1%) in patients treated with BPs and 17 fractures (37.8%) in patients who were not treated with BPs (odds ratio 11.3, 95% CI 5.7–22.3). Radiographic beaking was observed more frequently in patients treated with BPs than in patients not treated with BPs.