Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
Endocr Pract. 2013 May-Jun;19(3):e64-8. doi: 10.4158/EP12367.CR.
Bisphosphonates are the most common class of medications used to treat osteoporosis. Their widespread use has uncovered rare complications, including atypical femoral fractures (AFF). The pathogenesis of AFF is incompletely understood; however, if oversuppression of bone remodeling contributes to AFF, it is plausible that other potent antiresorptive agents, such as denosumab, could be associated with AFF as well.
We report a case of an 81-year-old woman with densitometric osteopenia, chronic kidney disease, and hyperparathyroidism, who was initiated on denosumab for elevated fracture risk. Approximately 6 months after her initial denosumab injection, she developed severe right groin and thigh pain without prior trauma.
A femoral radiograph was normal, without cortical thickening, but a magnetic resonance imaging revealed a transverse subtrochanteric insufficiency fracture with a medial defect involving 25% of the femoral cortex. She did not receive any further doses of denosumab. Bone turnover markers did not suggest oversuppression. Her fracture was treated conservatively with nonweight bearing status with resultant full recovery.
This fracture does not meet the current definition of an AFF as, for that definition, a lateral femoral location is required. This case does not provide conclusive evidence for a causal relationship between treatment with denosumab and this unusual fracture. It clearly illustrates, however, the occurrence of an unusual, nontraumatic subtrochanteric fracture in a patient treated with the potent antiresorptive agent denosumab with many features in common with bisphosphonate-associated AFF.
双膦酸盐是治疗骨质疏松症最常用的药物类别。它们的广泛使用揭示了罕见的并发症，包括非典型股骨骨折（AFF）。AFF 的发病机制尚未完全了解；然而，如果骨重建的过度抑制导致 AFF，那么其他强效的抗吸收剂，如地舒单抗，也可能与 AFF 相关。
我们报告了一例 81 岁女性患者，存在骨密度骨质疏松症、慢性肾脏病和甲状旁腺功能亢进症，因骨折风险升高而开始接受地舒单抗治疗。在最初接受地舒单抗注射约 6 个月后，她出现严重的右侧腹股沟和大腿疼痛，无外伤史。
股骨 X 线片正常，无皮质增厚，但磁共振成像显示横行转子下不全骨折，内侧缺损累及股骨皮质的 25%。她没有再接受地舒单抗治疗。骨转换标志物并未提示过度抑制。她的骨折采用非负重状态保守治疗，最终完全康复。
该骨折不符合当前 AFF 的定义，因为该定义需要外侧股骨位置。该病例并未提供地舒单抗治疗与这种不寻常骨折之间因果关系的确凿证据。然而，它清楚地说明了在接受强效抗吸收剂地舒单抗治疗的患者中发生了不寻常的、非创伤性转子下骨折，其具有与双膦酸盐相关的 AFF 许多共同特征。
