Department of Orthopaedic Surgery, Kyushu University, Higashi-ku, Fukuoka, Japan.
AJR Am J Roentgenol. 2010 Jul;195(1):W63-8. doi: 10.2214/AJR.09.3271.
The purpose of this article is to verify the hypothesis that osteonecrosis and subchondral insufficiency fracture of the femoral head can be differentiated on the basis of their appearance on MRI.
Between May 1998 and February 2009, we reviewed 30 consecutive hips in 30 patients, 60 years old or older at the time of onset of hip pain, with radiologic evidence of subchondral collapse of the femoral head and with both MR images and histologic results available. Both clinical and radiologic appearances were investigated. The patients were divided into two groups according to the shape of low-intensity bands on T1-weighted images. The first group showed concavity of the articular surface, which is characteristic of osteonecrosis, and the second group showed an irregular convexity of the articular surface, which is characteristic of subchondral insufficiency fracture.
Sixteen hips (53.3%) showed evidence of osteonecrosis, and 14 (46.7%) showed evidence of subchondral insufficiency fracture, which was consistent with the corresponding histopathologic diagnoses. In all cases of osteonecrosis, the patient had a history of either corticosteroid intake or alcohol abuse. Among patients with subchondral insufficiency fracture, the proportion of women was significantly higher than that among patients with osteonecrosis. A crescent sign (subchondral fracture) was present radiographically in about half of all cases in both groups.
The results of the present study suggest that the shape of the low-intensity band on MRI is useful for the differentiating subchondral insufficiency fracture from osteonecrosis. In addition, among osteoporotic elderly women without any history of corticosteroid intake or alcohol abuse, a diagnosis of subchondral insufficiency fracture should be considered.
本文旨在验证以下假说，即基于 MRI 上的表现，可对股骨头坏死和软骨下骨不全骨折进行鉴别。
1998 年 5 月至 2009 年 2 月，我们回顾了 30 例 30 髋患者的资料，这些患者均为 60 岁及以上，髋痛初发时存在股骨头软骨下骨塌陷的影像学证据，且均有 MRI 图像和组织学结果。我们对所有患者的临床表现和影像学表现进行了研究。根据 T1 加权图像上低信号带的形状，将患者分为两组。第一组表现为关节面凹陷，具有股骨头坏死的特征；第二组表现为关节面不规则凸起，具有软骨下骨不全骨折的特征。
16 髋（53.3%）表现为股骨头坏死，14 髋（46.7%）表现为软骨下骨不全骨折，这与相应的组织病理学诊断一致。所有股骨头坏死患者均有皮质类固醇摄入或酗酒史。软骨下骨不全骨折患者中，女性比例明显高于股骨头坏死患者。两组中约一半的病例在影像学上均存在新月征（软骨下骨折）。
本研究结果表明，MRI 上低信号带的形状有助于鉴别软骨下骨不全骨折和股骨头坏死。此外，对于无皮质类固醇摄入或酗酒史的骨质疏松老年女性，应考虑软骨下骨不全骨折的诊断。
