髌骨倾斜角动态变化分析对髌股关节不稳的诊断价值

To Evaluate the Diagnostic Value of the Dynamic Analysis of Patellofemoral Tilt Angle in Patellofemoral Instability

目的探讨膝关节伸直状态(0°位)和屈膝30°时髌骨倾斜角的变化大小对髌股关节不稳及其不稳分型的诊断价值。方法选取以膝关节膝前痛为主诉的58例患者为病变组,其中32例经手术证实,26例为影像测量证实,选取15例(30膝)无膝关节症的自愿者为正常对照组,均进行膝关节伸直状态下矢状位、横轴位及膝关节屈膝30°位垂直髌骨长径的横断面成像,在0°位图像上测量股骨外侧滑车的倾斜角、髌骨倾斜角、髌骨外移比值,在30°位图像上测量髌骨倾斜角、髌骨外移比值,并计算髌骨0°与30°髌骨倾斜角变化值。经独立样本t检验进行比较,并计算髌骨倾斜角变化值对髌股关节不稳各分型的诊断的敏感度和特异度。结果不稳组膝关节0°位时髌骨倾斜角(16.5±4.3)°。膝关节屈膝30°位时髌骨倾斜角为(14.4±3.5)°,不稳组髌骨0°位与屈膝30°位时髌骨倾斜角变化值为(8.4±3.2)°。正常对照组膝关节伸直位时髌骨倾斜角为(7.2±3.5)°,膝关节屈膝30°位时髌骨倾斜角为(3.4±2.6)°,髌骨0°位与屈膝30°位时髌骨倾斜角变化值为(2.2±1.5)°。患者组与对照组比较差异具有统计学意义(P<0.01)。30°位时髌骨倾斜角较0°位增大7例,30°位时髌骨倾斜角较0°位减小51例。其中髌骨倾斜角变化值增大(30°位髌骨倾斜角大于0°位髌骨倾斜角)为髌骨外移增加的敏感指标,其特异度和敏感度均为100%,髌骨倾斜角减小对髌骨倾斜型和髌骨外移减轻型诊断的敏感度及特异度分别为83%、64%,75%、61%。髌骨外侧倾斜角减小结合髌骨外移比值,对髌骨外移减轻型和单纯髌骨倾斜型诊断的敏感度和特异度均为100%。结论髌骨倾斜角变化值大小对髌骨关节不稳具有较高的诊断价值,结合髌骨外移比值对髌股关节不稳分型诊断具有很大价值。

Objective To evaluate the diagnostic value of the change of patellofemoral tilt angle（ PTA） with the knee unbend（ 0°） and flexing at 30° in patellofemoral instability and classification. Methods 58 cases with chief complaint of the anterior knee pain（ 32 cases confirmed by operation,26 cases confirmed by image analysis） were allocated in the lesion group while 15 healthy（ 30 knees） individuals served as normal controls. All cases were imaged in sagittal plane and transverse plane with knee straight position（ 0°）,and in the transverse plane perpendicular to patellar axis with knee flexion of30°. The condylus lateralis tilt angle,PTA and lateral patellar displacement were measured in images of 0° and 30°. The changes of PTA（ 0°to 30°） were measured,and were analyzed with t test. To evaluate the sensitivity and specificity of PTA to patellofemoral instability and classification. Results The PTA of the lesion group was（ 16. 5 ± 4. 3） ° in 0°position,was（ 14. 4 ± 3. 5） ° in 30°position. The change of PTA was（ 8. 4 ± 3. 2） ° from 0°position to 30°position. The PTA of the control group was（ 7. 2 ± 3. 5） ° in 0° position,was（ 3. 4 ± 2. 6） ° in 30° position. The change of PTA was（ 2. 2 ±1. 5） ° from 0°position to 30°position. There were significant statistical difference between the two group（ P 〈 0. 01）. The PTA of 7 cases was bigger in 30°position than 0°position. The PTA of 51 cases was smaller in 30°position than 0°position.The increment of PTA from 0°position to 30°position was a sensitive parameter of lateral patellar displacement. The sensitivity and specificity were 100%. The decrease of PTA reduce the diagnostic sensitivity and specificity of patellar tilt and lateral patellar displacement are 83% 、64%,75% 、61%. The decrease of PTA combined with lateral patellar displacement had 100% sensitivity and specificity to the diagnosis of simple patellar tilt. Conclusion The change of PTA had important diagnosis value to the patellofemoral instability. The PTA combined with lateral patellar displacement had important diagnosis value to the patellofemoral instability classification.