Failure load of the femoral insertion site of the anterior cruciate ligament in a porcine model: comparison of different portions and knee flexion angles

Abstract

Background This study compared the failure load of the femoral insertion site of the anterior cruciate ligament between different portions and knee flexion angles. Methods In total, 87 fresh-frozen, porcine knees were used in this study. Three knees were used for histological evaluation; the remaining 84 knees were randomly divided into 4 groups: anterior anteromedial bundle, posterior anteromedial bundle, anterior posterolateral bundle, and posterior posterolateral bundle groups (n=21 per group). The anterior cruciate ligament femoral insertion site was divided into these four areas and excised, leaving a 3-mm square attachment in the center of each bundle. Tibia-anterior cruciate ligament-femur complexes were placed in a material testing machine at 30°, 120°, and 150° of knee flexion (n=7), and the failure load for each portion was measured under anterior tibial loading (0.33 mm/s). Results Histological study showed that the anterior cruciate ligament femoral insertion site consisted of direct and indirect insertions. Comparison of the failure load between the knee flexion angles revealed that all the failure loads decreased with knee flexion; significant decreases were observed in the failure load between 30 and 150° knee flexion in the posterior anteromedial bundle and posterior posterolateral bundle groups. Comparison of the failure load according to different portions revealed a significant difference between the anteromedial and posterolateral bundle groups at 150° of knee flexion, but no significant difference among the groups at 30° of flexion. Conclusions Although the failure load of the posterior portion decreased significantly in the knee flexion position, it (mainly consisting of indirect insertion) plays a significant role against anterior tibial load in the knee extension position; this appears to be related to the characteristics of the insertion site. Reflecting the complex structure and function of the ACL, this study showed that the failure load of the femoral insertion site varies with differences in positions and knee flexion angles.

Self‐Powered Flexible Sensor Array for Dynamic Pressure Monitoring

“…The porcine knee was consistently flexed at an initial angle of 30°. [ 56 ] Notably, during flexion and extension, the pressure exerted on the medial condyle of the articular disc outweighed that exerted on the lateral condyle. Upon flexion to 60°, the pressure values of the third channel of the medial and lateral condyles were recorded as 68.4 and 40.6 N (voltage amplitudes of 0.9 and 0.65 V).…”

Comparison of the morphology of the anterior cruciate ligament and related bony structures between pigs and humans

“…Observation in this current study showed that the porcine ACL insertion can be divided into two parts, namely the direct insertion and indirect insertion. Yamauchi et al (32) also observed in mature porcine knees that the anterior attachment of the femoral ACL site was a direct insertion and the posterior attachment could be characterized as an indirect insertion. This finding is consistent with the current study, and with previous studies on human knees (17,18,33).…”