Cegarra Navarro M F, Martínez Fernández M, Blanco Barrio A, Lloret Estañ F
Servicio de Radiodiagnóstico, Hospital General Universitario Morales Meseguer, Murcia, España.
Radiologia. 2010 May-Jun;52(3):234-40. doi: 10.1016/j.rx.2009.12.013. Epub 2010 Apr 10.
To analyze possible underlying causes of spontaneous osteonecrosis of the knee in adults in function of the lesion's behavior on magnetic resonance imaging (MRI): acute lesion (insufficiency fractures) or chronic lesion (osteoarthritic degeneration).
We retrospectively evaluated knee MRI studies in 48 patients who fulfilled criteria for spontaneous osteonecrosis. A total of 51 subchondral lesions were included and classified in two groups: those in which linear images were present (Group A) and those in which linear images were not present (Group B). We recorded the location and size of the lesions, their signal intensity, their relation with bone edema, ipsilateral meniscal tear and abnormalities in the adjacent cartilage, as well as the presence of osteoarthritis.
We studied 28 men and 20 women (mean age, 55.1+/-18.0 years). Linear images were present in 58.5% of lesions (group A) and absent in 41.2% (group B). The most common location in both groups was the internal femoral condyle (56.7% in group A and 52.4% in group B), and 88.2% of lesions were hypointense on T1-weighted and fat suppressed proton density sequences. The mean size of the anteroposterior and transversal diameters was 11.9+/-3.6 x 9.4+/-3.9 mm in group A and 10.9+/-5.1 x 10.5+/-4.5 mm in group B. The predominant bone edema was severe (grade 2-3) in group A and mild (grade 0-1) in group B (p=0.033). Defects in the cartilage ipsilateral to the subchondral lesion were more common in group B than in group A, although this difference was not significant (76.2% and 56.7%, respectively; p=0.33). The frequency of ipsilateral meniscal tear was similar in the two groups (56.7% in group A and 57.1% in group B; p=0.97).
Knowing the MRI findings for spontaneous osteonecrosis and evaluating other data (type of lesion, bone edema, meniscal tear, and ipsilateral cartilage defects) can help determine the primary predisposing process. Linear lesions might be related to an acute process (insufficiency fractures) and non-linear lesions might be related to a chronic process (osteoarthritis).
根据磁共振成像（MRI）上病变的表现，分析成人膝关节自发性骨坏死可能的潜在病因：急性病变（应力性骨折）或慢性病变（骨关节炎退变）。
我们回顾性评估了48例符合自发性骨坏死标准患者的膝关节MRI研究。共纳入51个软骨下病变，并分为两组：存在线性影像的病变（A组）和不存在线性影像的病变（B组）。我们记录了病变的位置和大小、信号强度、与骨水肿的关系、同侧半月板撕裂及相邻软骨的异常情况，以及骨关节炎的存在情况。
我们研究了28例男性和20例女性（平均年龄55.1±18.0岁）。58.5%的病变（A组）存在线性影像，41.2%（B组）不存在。两组中最常见的部位均为股骨内侧髁（A组为56.7%，B组为52.4%），88.2%的病变在T1加权像和脂肪抑制质子密度序列上呈低信号。A组前后径和横径的平均大小为11.9±3.6×9.4±3.9mm，B组为10.9±5.1×10.5±4.5mm。A组主要的骨水肿为重度（2 - 3级），B组为轻度（0 - 1级）（p = 0.033）。软骨下病变同侧的软骨缺损在B组比A组更常见，尽管差异不显著（分别为76.2%和56.7%；p = 0.33）。两组同侧半月板撕裂的发生率相似（A组为56.7%，B组为57.1%；p = 0.97）。
了解自发性骨坏死的MRI表现并评估其他数据（病变类型、骨水肿、半月板撕裂和同侧软骨缺损）有助于确定主要的易感过程。线性病变可能与急性过程（应力性骨折）相关，而非线性病变可能与慢性过程（骨关节炎）相关。
