Fukuoka Natsuko, Oe Keisuke, Sakurai Atsushi, Niikura Takahiro, Kuroda Ryosuke, Yamamoto Tetsuji
Department of Orthopaedic Surgery, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
J Orthop Case Rep. 2020 Jul;10(4):42-44. doi: 10.13107/jocr.2020.v10.i04.1794.
Subcapital fractures following internal fixation of an intertrochanteric fracture are relatively rare. It has been reported that these fractures are caused by improper placement of implants, osteoporosis, and any trauma episode. We report a rare case of subcapsular fracture possibly caused by whole femoral head necrosis following intertrochanteric fracture treatment.
An 88-year-old woman fell and sustained an intertrochanteric fracture of the left femur. She was treated with a short femoral nail (SFN) and 3 months after the surgery, bone union was observed. One year after the internal fixation of the intertrochanteric fracture, she complained of the left hip joint pain without any trauma, and the X-ray showed a subcapital fracture of the femur. She underwent nail removal and was treated with a bipolar hemiarthroplasty. Magnetic resonance imaging showed a change in the signal intensity of the entire head, and pathological findings revealed osteonecrosis. Normally, the reaction of bone resorption occurs below the necrosis area. We believe that the avascular necrosis (AVN) of the whole femoral head made the subcapital area fragile, resulting in a subcapital fracture.
We should consider AVN of the whole femoral head as a potential cause of subcapital fracture after SFN fixation of intertrochanteric fractures.
股骨转子间骨折内固定术后的股骨颈骨折相对少见。据报道，这些骨折是由植入物放置不当、骨质疏松以及任何外伤事件引起的。我们报告一例罕见的股骨颈下骨折病例，可能是由于股骨转子间骨折治疗后全股骨头坏死所致。
一名88岁女性跌倒后发生左股骨转子间骨折。她接受了短股骨钉（SFN）治疗，术后3个月观察到骨愈合。股骨转子间骨折内固定术后一年，她无任何外伤却抱怨左髋关节疼痛，X线显示股骨颈下骨折。她接受了取钉手术，并接受了双极半髋关节置换术。磁共振成像显示整个股骨头信号强度改变，病理结果显示为骨坏死。正常情况下，骨吸收反应发生在坏死区域下方。我们认为全股骨头缺血性坏死（AVN）使股骨颈下区域变得脆弱，导致了股骨颈下骨折。
我们应将全股骨头缺血性坏死视为股骨转子间骨折采用SFN固定后股骨颈下骨折的一个潜在原因。
