Background A number of recent case reports and series have identified atypical fractures of the femoral shaft. Atypical femoral fractures (AFFs) with lack of trauma or less-energy have been reported to relate using of the bisphosphonates (BPs) and glucocorticoids (GCs) for a long time, affecting collagen diseases1,2.
Objectives We have analyzed the AFFs in rheumatic patients in the highly super aging area of North Japan, in which the rate more than 65 year-old people in the population was 28%.
Methods We investigated retrospectively all cases of AFF summarized by the American Society for Bone and Mineral Research (ASBMR) Task Force 20131 including affected rheumatic disease patients in all hospitals of our prefectural area from 2009 to 2014. Two independent orthpaedic surgeons have diagnosed blindly AFF and estimated proximal femoral geometry by using radiographic analyses. Observation end of this study was settled on Feb 2016.
Results We have 86 cases 99 AFFs in our prefectural area from 2009 to 2014 (1.43 cases/100,000 person/year). The rheumatic patients with AFFs were eleven femurs in eight women in that periods and increased year by year (Fig. 1). Three cases have bilateral AFFs (six femurs, 55%). The mean age of them was 54.9 year-old (33–80). As comorbid conditions, five patients have systematic lupus erythematosus, two dermatomyositis and rheumatoid arthritis, one polyarteritis nodosa and systemic sclerosis. Fracture types were seven subtrochanteric and four diaphyseal femoral fractures. Mean femoral neck angle was 133 degrees (120–141) and femoral shaft angle was 6.1 degree (3–10). Six patients with AFF had prodromal pain (55%). All patients received BPs and all but one prednisolone (PSL). Mean duration of receiving those drugs was 52 months (24–120) and 109 months (36–120), respectively. Mean dosage of PSL was 14 mg/day (0–30). In addition, bilateral AFF group has more PSL dose and duration of PSL, more varus deformity of their femur compared to unilateral AFF group (p<0.05). After affecting the fractures, BPs were quitted in seven femurs except four. The surgery using intramedullary nail fixation were performed in all cases excluding one femur using a locking plate. Teriparatide and therapy of low-intensity pulsed ultrasound was induced for five cases after healing their operated wounds. Mean duration of post-operative observation was 28 months (12–70). At the latest follow-up, ten femurs were observed the sign of union at fracture site on X-ray or computed tomography of their femurs, but not one femur. Mean duration of union of the fracture site was 12.6 months (6–24) in ten femurs.
Conclusions Eleven AFFs were observed in 2009–14 in rheumatic patients and the numbers were increased year by year in the highly super aging area of North Japan. The careful management and treatment for the AFFs in rheumatic patients are required even after the surgery, because our all cases have been observed the delayed union or non-union of fracture site at their latest follow-up3. In addition, AFF patients who show varus deformity of their femurs and receive much dose of PSL have highly risk of contralateral AFF.
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Thompson RN, et al. JBJS, 2012.
Acknowledgement We really appreciate all members of Yamagata Prefectural Committee of Atypical Femoral Fractures Study group.
Disclosure of Interest None declared