Tsukamoto Hiroaki, Saito Hidetomo, Saito Kimio, Yoshikawa Takayuki, Oba Masashi, Sasaki Kana, Sato Chie, Akagawa Manabu, Takahashi Yasuhiro, Miyakoshi Naohisa, Shimada Yoichi
Department of Orthopedic Surgery, Omori Municipal Hospital, Akita, Japan; Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan; Department of Internal Medicine, Tazawako Municipal Hospital, Akita, Japan; Akita Sports Arthroscopy Knee Group (ASAK), Akita, Japan.
Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan; Akita Sports Arthroscopy Knee Group (ASAK), Akita, Japan.
Knee. 2020 Jun;27(3):838-845. doi: 10.1016/j.knee.2020.04.007. Epub 2020 Apr 22.
Spontaneous osteonecrosis of the knee (SONK) is one of the acute knee pain disorders arising in elderly patients. The presence of knee varus alignment and the size of necrotic area have been reported as the negative prognostic factors in prior studies. However, no previous study has yet clarified the radiological analysis of the lower extremity in SONK compared with that in osteoarthritis. The purpose of this study was therefore to identify the radiographic findings of the lower extremity in SONK.
Sixty-three knees of Kellgren-Lawrence classification grade 1 or 2 without any trauma treated between April 2012 and March 2014 were enrolled in this study. These knees were divided into two groups according to their magnetic resonance imaging (MRI) findings: SONK group (31 knees) and OA group (32 knees). Using a long leg standing X-ray, femorotibial angle (FTA), mechanical axis deviation (MAD), mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA) and joint line convergent angle (JLCA) were compared between groups. Correlation between each parameter and the width ratio (WR) of the necrotic lesion were analyzed.
FTA, MAD, MPTA and JLCA showed significant differences between the SONK and OA groups. In the SONK group, FTA was positively correlated with WR, and, MAD and MPTA was negatively correlated with WR.
Compared with OA, SONK is associated with a significantly larger varus deformity at the proximal tibia, and larger joint play in the coronal plane.
膝关节自发性骨坏死（SONK）是老年患者出现的急性膝关节疼痛疾病之一。既往研究报道膝关节内翻畸形的存在以及坏死区域的大小为不良预后因素。然而，既往尚无研究阐明与骨关节炎相比，SONK患者下肢的影像学分析情况。因此，本研究的目的是确定SONK患者下肢的影像学表现。
纳入2012年4月至2014年3月间治疗的63例Kellgren-Lawrence分级为1级或2级且无任何创伤的膝关节。根据磁共振成像（MRI）结果将这些膝关节分为两组：SONK组（31例膝关节）和骨关节炎（OA）组（32例膝关节）。使用长腿站立位X线片，比较两组之间的股胫角（FTA）、机械轴偏移（MAD）、机械性股骨远端外侧角（mLDFA）、胫骨近端内侧角（MPTA）和关节线汇聚角（JLCA）。分析各参数与坏死灶宽度比（WR）之间的相关性。
SONK组和OA组之间FTA、MAD、MPTA和JLCA存在显著差异。在SONK组中，FTA与WR呈正相关；而MAD和MPTA与WR呈负相关。
与OA相比，SONK与胫骨近端明显更大的内翻畸形以及冠状面更大的关节活动度相关。
