Genovese E, Angeretti M G, Ronga M, Leonardi A, Novario R, Callegari L, Fugazzola C
Cattedra di Radiologia, Università dell'Insubria, Ospedale di Circolo, Fond. Macchi, Viale Borri 57, I-21100, Varese, Italy.
Radiol Med. 2007 Oct;112(7):1036-48. doi: 10.1007/s11547-007-0204-y. Epub 2007 Oct 21.
The purpose of our study was to evaluate the usefulness of magnetic resonance imaging (MRI) in the follow-up of patients treated with collagen meniscus implant (CMI) and to identify MRI patterns suitable for defining its evolution.
Between March 2001 and June 2003, CMI was performed on 40 patients (27 men and 13 women, age 23-58 years, median 41 years) affected by irreparable medial meniscal lesions. All patients underwent MRI follow-up at 6 months and 1 year and 16 patients 2 years after the operation; 12 patients underwent second-look arthroscopy with implant biopsy. All MRI examinations were performed with a 1.5-T unit using GE T2*, spin-echo (SE) T1, and FatSat fast spin-echo (FSE) DP and T2-weighted sequences, with different orientations. At 24 months, MR arthrography was also performed. Implant evolution was assessed on the basis of MRI direct and indirect criteria. Direct criteria were morphology and signal intensity of the collagen meniscus/residual meniscus complex. Based on these characteristics, three pattern were identified and classified from 1 to 3, where a higher score corresponded to characteristics approaching those of the normal meniscus. Indirect criteria were chondral surface and subchondral bone marrow oedema at implant site and associated synovial pathology.
MRI follow-up at 6 months showed CMI shape and size to be normal (type 3) in 35/40 patients and type 2 in 5/40 patients. CMI signal intensity was type 1 in 32/40 patients and type 2 in 8/40. An interface between prosthetic and native meniscus was identified in 27/40 patients. Chondral lesions were present in 3/40 cases and subchondral bone marrow oedema in 8/40 cases. Reactive synovial effusion was seen in 2/40 patients. MRI follow-up at 12 months showed CMI shape and size to be normal (type 3) in 33/40 patients and type 2 in 7/40. Signal intensity was type 1 in 14/40 patients and type 2 in 26/40 patients. The interface was seen in 19/40 patients. The associated chondral lesions were unchanged, whereas subchondral bone marrow oedema was present in 3/40 patients. No synovial reaction was detected. At 24 months, CMI size was type 3 in 9/16 patients, type 2 in 6/16, and type 1 in one patient in whom the implant could not be identified, as it had been totally resorbed. CMI signal intensity was type 2 in 11/15 and type 3 in 4/16. The interface was identified in seven patients. MR arthrography depicted two additional chondral lesions and enabled correct grading of all lesions. Subchondral bone marrow oedema was present in two patients only.
MRI enables morphological and structural changes of CMI to be monitored over time. Follow-up can be extended beyond 2 years, until the CMI has stabilised and subchondral bone marrow oedema has completely resolved. In the single case with a poor CMI outcome, no related direct or indirect signs were identified.
本研究的目的是评估磁共振成像（MRI）在胶原蛋白半月板植入物（CMI）治疗患者随访中的作用，并确定适合定义其演变的MRI模式。
2001年3月至2003年6月期间，对40例（男27例，女13例，年龄23 - 58岁，中位年龄41岁）患有无法修复的内侧半月板损伤的患者进行了CMI治疗。所有患者在术后6个月、1年进行了MRI随访，16例患者在术后2年进行了随访；12例患者进行了二次关节镜检查并取植入物活检。所有MRI检查均使用1.5-T设备，采用GE T2*、自旋回波（SE）T1以及脂肪抑制快速自旋回波（FSE）DP和T2加权序列，扫描方向不同。在24个月时，还进行了磁共振关节造影。根据MRI的直接和间接标准评估植入物的演变情况。直接标准为胶原蛋白半月板/残余半月板复合体的形态和信号强度。基于这些特征，确定了三种模式并从1到3进行分类，分数越高表示特征越接近正常半月板。间接标准为植入部位的软骨表面和软骨下骨髓水肿以及相关的滑膜病变。
6个月时的MRI随访显示40例患者中35例CMI的形状和大小正常（3型），5例为2型。40例患者中32例CMI信号强度为1型，8例为2型。40例患者中有27例发现假体与天然半月板之间的界面。40例中有3例存在软骨损伤，8例有软骨下骨髓水肿。40例中有2例出现反应性滑膜积液。12个月时的MRI随访显示40例患者中33例CMI形状和大小正常（3型），7例为2型。40例患者中14例信号强度为1型，26例为2型。40例中有19例可见界面。相关软骨损伤无变化，40例中有3例存在软骨下骨髓水肿。未检测到滑膜反应。24个月时，16例患者中9例CMI大小为3型，6例为2型，1例患者的植入物已完全吸收无法识别，为1型。16例中有11例CMI信号强度为2型，4例为3型。7例患者发现界面。磁共振关节造影显示另外2例软骨损伤，并能对所有损伤进行正确分级。仅2例患者存在软骨下骨髓水肿。
MRI能够随时间监测CMI的形态和结构变化。随访可延长至2年以上，直至CMI稳定且软骨下骨髓水肿完全消退。在CMI治疗效果不佳的单个病例中，未发现相关的直接或间接征象。
