膝关节骨坏死样病变的MRI与组织病理学初步对照研究

Primary study on relationship between MRI appearance and pathology in knee osteonecrosis-like lesion

目的通过研究膝关节各种骨坏死样MRI信号与组织病理学变化的关系，提高MRI在诊断膝关节骨坏死中的价值，揭示各种膝关节骨坏死样MRI信号的组织病理学本质。方法对2006年1～7月在本中心行TKA手术的29例患者全部行患膝关节X线片检查，其中25例行患膝关节MRI检查，对其中软骨下骨存在骨坏死样MRI信号（脂肪信号型：T1加权高信号区，T2加权中等信号区；血液信号型：T1加权及T2加权均为高信号区；水样信号型：T1加权低信号区T2加权高信号区；纤维信号型：T1加权及T2加权均为低信号区）的5例患者（男1例．女4例，平均年龄65．8岁）术后取截骨标本，通过精确的测片定位截取标本，对异常信号部位骨质行HE染色光镜检查，并与术前MRI进行对照。结果5例患者术前MRI共发现8处骨坏死样异常信号，其中股骨内髁5处，内侧胫骨平台3处；MRI信号分类：无脂肪信号型及血液信号型，水样信号型6处，纤维信号型2处。相应组织学检查均证实为骨坏死的病理学Ⅱ～Ⅳ期（Ⅰ期：坏死期；Ⅱ期：修复期；Ⅲ期：坏死骨组织主要修复期；Ⅳ期：继发骨关节炎期）。结论膝关节骨坏死样病变的MRI分型反映了不同的病理学基础，根据不同的MRI信号分型可以大致判断骨坏死的病理学分期。

Objective To increase the diagnosis value of MRI on knee osteonecrosis and to reveal the pathological essence of various osteonecrosis-like signals by studying their relationship with pathological change. Methods To prospectively examine 29 consecutive patients treated by total knee arthroplasty in our centre from January 2006 to July 2006 with radiography （29 of 29） and MRI（25 of 29）. Bone specimens of 5 patients （1 man and 4 women with an average age of 65.8 years） with subcondralosteonecrosis-like signal （fat signal type： high intensity zone in T1 weighted and equal intensity zone in T2 weighted：blood signal type： high intensity zone in both T1 and T2; water signal type：low intensity in T1 and high intensity in T2;fibcr signal type： low intensity in both T1 and T2） were examined with microscope after HE stain and the results were compared with preoperative MRL Results Eight osteonecrosis like focus was found in the 5 patients： 5 at medial femoral condyle and 3 at medial tibial condyle. Cation of MRI signal： No fat signal type and blood signal type were found; There were 6 water signal type and 2 fiber signal type. Histological observation confirmed all focuses were in stage Ⅱ - Ⅳ（Ⅰ：necrosis stage, Ⅱ： reparation stage, Ⅲ ： Necrotic hone tissue main reparation stage, Ⅳ ：secondary osteoarthritis stage）. Conclusion The classification of knee osteonccrosis reflects various pathological bases, the pathological stage of osteonecrosis can be identified by various MRI signal.