Kubo Yusuke, Motomura Goro, Ikemura Satoshi, Sonoda Kazuhiko, Hatanaka Hiroyuki, Utsunomiya Takeshi, Baba Shoji, Nakashima Yasuharu
Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
Int Orthop. 2018 Jul;42(7):1449-1455. doi: 10.1007/s00264-018-3836-8. Epub 2018 Feb 18.
The location of the necrotic lesion is one of the important factors for collapse in osteonecrosis of the femoral head (ONFH). The significance of anterior localization has been little studied. This study evaluated the effects of anterior boundary of a necrotic lesion on collapse.
We reviewed the outcomes of 113 consecutive non-collapsed asymptomatic hips in 98 ONFH patients with mean follow-up of 4.7 years (2.0-11.8) after the initial magnetic resonance (MR) imaging. The presence or absence of collapse was investigated using follow-up radiographs. The location of the anterior boundary of a necrotic lesion was assessed using the anterior necrotic angle between the midline of the femoral neck shaft and the line passing from the femoral head centre to the anterior boundary on mid-oblique MR imaging. Multivariate analysis was performed to identify risk factors for collapse, and further analyses were executed according to the lateral boundary of the necrotic lesion.
During the follow-up period, collapse was confirmed in 61 hips (54.0%). Multivariate analysis revealed that the anterior necrotic angle was independently associated with collapse as well as the lateral boundary of the necrotic lesion. When the lateral boundary was located at the middle third of weight-bearing portion (32 hips), that was generally categorized as a low risk of collapse, all five cases with anterior necrotic angle ≥ 79° developed collapse, whereas only one of 27 cases (3.7%) with an anterior necrotic angle < 79° developed collapse (p < 0.0001).
This study indicates that ONFH patients with anterior localization of a necrotic lesion can develop collapse even if the necrotic lesion is medially located.
坏死病灶的位置是股骨头坏死（ONFH）塌陷的重要因素之一。关于前部定位的意义研究较少。本研究评估坏死病灶的前部边界对塌陷的影响。
我们回顾了98例ONFH患者113个连续未塌陷无症状髋关节的结果，初始磁共振（MR）成像后平均随访4.7年（2.0 - 11.8年）。使用随访X线片调查是否发生塌陷。在股骨颈干中线与从股骨头中心到中斜位MR成像上前部边界的连线之间的前部坏死角，用于评估坏死病灶前部边界的位置。进行多因素分析以确定塌陷的危险因素，并根据坏死病灶的外侧边界进行进一步分析。
随访期间，61个髋关节（54.0%）证实发生塌陷。多因素分析显示，前部坏死角以及坏死病灶的外侧边界与塌陷独立相关。当外侧边界位于负重区中三分之一时（32个髋关节），通常归类为塌陷低风险，前部坏死角≥79°的所有5例均发生塌陷，而前部坏死角<79°的27例中仅1例（3.7%）发生塌陷（p < 0.0001）。
本研究表明，坏死病灶前部定位的ONFH患者即使坏死病灶位于内侧也可能发生塌陷。
