Watanabe Yo, Kondo Naoki, Fukuhara Tomomi, Imai Norio, Yamada Masahiko, Endo Naoto
Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-Ku, Niigata 951-8510, Japan.
Division of Comprehensive Musculoskeletal Medicine, Niigata University Graduate School of Medical and Dental Sciences (Orthopedic Surgery), 1-757 Asahimachi-dori, Chuo-Ku, Niigata 951-8510, Japan.
Case Rep Orthop. 2021 Mar 20;2021:6624414. doi: 10.1155/2021/6624414. eCollection 2021.
Atypical femoral fracture is a low-energy stress fracture in the subtrochanteric region or the femoral shaft and is a complication of the long-term use of bisphosphonates. Histopathological findings of atypical femoral fractures have not been clarified. Herein, we report the case of a 61-year-old woman who fell while walking, which prompted her to visit our facility. She had a 7-year history of alendronate use to treat osteoporosis. A radiograph showed an atypical subtrochanteric femoral fracture, following which she underwent a primary surgery, where an intramedullary femoral nail was used. Implant breakage was discovered 8 weeks after the primary surgery. The patient underwent a revision surgery in which the entry point for the revised intramedullary hole was created to prevent varus position. The lag screw was successfully inserted into the center of the femoral head. Cancellous bone, isolated from the right ilium, was autogenously implanted into the fracture site. Fracture healing was promoted using low-intensity pulse ultrasonography. Callus formation was detected on a radiograph, and full weight-bearing was advised 12 weeks after the revision surgery. The fracture had healed completely at 13 months after the revision surgery. The patient was able to walk without support and could independently perform activities of daily life. Laboratory findings suggested that the concentrations of her bone formation markers were normal, while those of bone resorption markers were elevated. Iliac bone histomorphometry did not reveal severely suppressed bone turnover. In the cortex of fracture site, the lacunar density was markedly lower than the osteocyte density, and microcracks were detected, suggesting impaired osteocyte function and a low potential for fracture healing. This case is notable because it helps to clarify the histopathological findings of atypical femoral fractures.
非典型股骨骨折是转子下区域或股骨干的低能量应力性骨折，是长期使用双膦酸盐类药物的并发症。非典型股骨骨折的组织病理学表现尚未明确。在此，我们报告一例61岁女性病例，该患者在行走时摔倒，随后前来我院就诊。她有7年使用阿仑膦酸钠治疗骨质疏松症的病史。X线片显示为非典型转子下股骨骨折，随后她接受了一期手术，使用了股骨髓内钉。一期手术后8周发现植入物断裂。患者接受了翻修手术，术中创建了用于翻修髓内孔的入口点以防止内翻位。拉力螺钉成功插入股骨头中心。从右侧髂骨获取的松质骨被自体植入骨折部位。使用低强度脉冲超声促进骨折愈合。X线片检测到骨痂形成，翻修手术后12周建议完全负重。翻修手术后13个月骨折完全愈合。患者能够独立行走，可自主进行日常生活活动。实验室检查结果表明，她的骨形成标志物浓度正常，而骨吸收标志物浓度升高。髂骨组织形态计量学未显示骨转换严重受抑制。在骨折部位的皮质中，骨陷窝密度明显低于骨细胞密度，且检测到微裂纹，提示骨细胞功能受损且骨折愈合潜力低。该病例值得关注，因为它有助于明确非典型股骨骨折的组织病理学表现。
