后十字韧带完整性对股骨内髁生物力学特性的影响

 目的 探讨后十字韧带(posterior cruciate ligament, PCL)及其各分束的生物力学功能.以及 PCL完整性对股骨内髁生物力学特性的影响。方法 12具新鲜成人尸体膝关节标本在不同轴向载荷(0~800N)和不同屈曲角度(膝关节屈曲 0°、30°、60°和 90°)进行生物力学测试。PCL完整、前外侧束(anterolateral bundle.ALB)切断、后内侧束(posteromedial bundle,PMB)切断和 PCL完全切断顺序进行生物力学测试.分别测量加载后股骨内髁中部的应变。结果 0°位.各级载荷下 PMB切断和 PCL完全切断均引起股骨内髁应变增加.ALB切断对股骨内髁应变无明显影响.且在各级载荷下 PCL完全切断组股骨内髁的应变绝对值较 PMB切断组无明显增加。 30°、60°和 90°位.大载荷下 ALB切断和各级载荷下 PCL完全切断均引起股骨内髁应变增加.小载荷下ALB切断和各级载荷下PMB切断对股骨内髁应变无明显影响.且大部分载荷下 PCL完全切断组股骨内髁的应变绝对值较 ALB切断组明显增加。结论 在膝关节屈伸过程中 ALB和 PMB均有一定的稳定作用.伸直位 PMB对稳定起绝大部分作用.而屈曲位 ALB对稳定起大部分作用.且 PCL部分或完全断裂在屈伸过程中对股骨内髁均可产生不良的生物力学影响。

Effect of PCL integrity on biomechanical features of the medial femoral condyle

Objective To explore the biomechanical function of PCL and its different bundles and examine the biomechanical impact of posterior cruciate ligament (PCL) integrity on the medial femoral condyle. Methods Twelve fresh human cadaveric knee specimens were subjected to different axial load (0-800 N) at 0°, 30°,60°, and 90°of knee flexion. Four surgical treatments were carried out for biomechanical testing: PCL intact, anterolateral bundle (ALB) rupture, posteromedial bundle (PMB) rupture and PCL rupure. During the test, strains of middle part of the medial femoral condyle were calculated. Results At O°knee flexion, increasing strain of the medial femoral condyle was detected in PMB rupture and PCL rupture under all loading conditions. No significant difference of strain of the medial femoral condyle was noted between PCL intact and ALB rupture under any loading conditions. Compared to PMB rupture, PCL rupture had not higher strain of the medial femoral condyle under all loading conditions. At 30°, 60° and 90° knee flexion, increasing strain of the medial femoral condyle was noted in ALB rupture under higher loading conditions and PCL rupture under all loading conditions. ALB rupture under lower loading conditions and PMB rupture under all loading conditions did not significantly increased strain of the medial femoral condyle. PCL rupture had higher strain of the medial femoral condyle than ALB rupture under most of loading conditions.Conclusion The data suggest that PMB is the major stabilizing bundle of PCL in full extension, ALB is the major stabilizing bundle of PCL in knee flexion, and both bundles function through the ROM in a codominant fashion. Partial and complete ruptures of PCL may have hazardous biomechanical impacts on the medial femoral condyle during normal movement.