背景:在内侧单房室膝关节置换术(UKA)之前,需要明确外侧室的软骨质量。推荐使用外翻应力X线片作为首选工具。一些研究也表明磁共振成像(MRI)具有较高的诊断价值。所以,我们进行了这项研究,以比较外翻应力射线照相外侧关节间隙宽度(LJSW)和MRI分级是否可以准确反映软骨质量及其对UKA合适患者的筛查价值。
方法:前瞻性地纳入了UKA的一百三十八个膝盖。采取外翻应激X线片测量LJSW。LJSW>4mm被认为是正常的并且适合于UKA。对于股骨外侧髁的承重区软骨,术前通过MRI评估Recht分级。Recht≤2级视为非高级别损伤,而Recht>2级视为高级别损伤。Outerbridge等级是金标准,并在术中进行评估。Outerbridge等级0-2(非高级别损伤)的患者接受了UKA,外桥3-4级(高级别损伤)的患者接受了全膝关节置换术(TKA)。计算了用于选择UKA候选人的外翻应力X线片和MRI的诊断参数,绘制了受试者工作特性曲线。P<0.05被认为是显著的。
结果:在138个膝盖中,120接受UKA,18人接受了TKAs。在选择UKA候选人方面,MRI(95.0%)和外翻应力片(96.7%)的敏感性接近,和特异性,准确度,MRI的阳性预测值和阴性预测值(94.4%,94.9%,99.1%,73.9%,分别)高于外翻应激X光片(5.9%,85.5%,88.0%,20.0%,分别)。MRI(0.950)和LJSW(0.602)之间的曲线下面积(AUC)差异有统计学意义(P=0.001)。
结论:与外翻应力X线片相比,MRI对诊断外侧负重软骨损伤具有很好的评价价值,可作为选择合适UKA患者的可靠工具。
BACKGROUND: The cartilage quality of the lateral compartment needs to be clarified prior to medial unicompartmental knee arthroplasty (UKA). Valgus stress radiograph has been recommended as the preferred tool. Some studies also show that magnetic resonance imaging (MRI) has a higher diagnostic value. So, we conducted this study to compare whether valgus stress radiographic lateral joint space width (LJSW) and MRI grading can accurately reflect cartilage quality and its screening value for UKA-suitable patients.
METHODS: One hundred and thirty eight knees proposed for UKA were enrolled prospectively. Valgus stress radiograph was taken to measure LJSW. LJSW > 4 mm was considered normal and suitable for UKA. For weight-bearing area cartilage of lateral femoral condyle, Recht grade was assessed by MRI preoperatively. Recht grades ≤ 2 were treated as non-high-grade injuries while Recht grades > 2 were treated as high-grade injuries. Outerbridge grade was the gold standard and was assessed intraoperatively. Patients with Outerbridge grades 0-2 (non-high-grade injuries) underwent UKA, and patients with Outerbridge grades 3-4 (high-grade injuries) underwent total knee arthroplasty (TKA). The diagnostic parameters of valgus stress radiograph and MRI for the selection of UKA candidates were calculated, and receiver operating characteristic curves were drawn. P < 0.05 was considered significant.
RESULTS: Of 138 knees, 120 underwent UKAs, and 18 underwent TKAs. In terms of selecting UKA candidates, the sensitivity was close between MRI (95.0%) and valgus stress radiograph (96.7%), and the specificity, accuracy, positive predictive value and negative predictive value of MRI (94.4%, 94.9%, 99.1%, 73.9%, respectively) were higher than that of valgus stress radiograph (5.9%, 85.5%, 88.0%, 20.0%, respectively). The difference in area under the curve (AUC) between MRI (0.950) and LJSW (0.602) was significant (P = 0.001).
CONCLUSIONS: Compared with valgus stress radiograph, MRI has excellent evaluation value in diagnosing lateral weight-bearing cartilage injuries and can be used as a reliable tool for selecting suitable UKA patients.