Sectioning of the anterior intermeniscal ligament changes knee loading mechanics

• Ollivier Matthieu
• Falguières Julie
• Pithioux Martine
• Boisrenoult Philippe
• Beaufils Philippe
• Pujol Nicolas

Introduction: The aim of this cadaver research project was to describe the biomechanical consequences of AIML resection on menisci function under load conditions in full extension and 60° flexion. Methods: Ten unpaired fresh frozen cadaveric knees were dissected leaving the knee joint intact with its capsular and ligamentous attachments. The femur and tibia were sectioned 15 cm from the joint line and mounted onto loading plateform. A linear motion x-y table allows the tibial part of the joint to freely translate in anterior-posterior direction. K-scan sensors, were used to define contact area, contact pressure and position of pressure center of application (PCOA). Two series of analysis were planed: before and after AIML resection, mechanical testing were performed with specimens in full extension and 60° of flexion to approximate heel strike and foot impulsion during the gait. A standard compression load of 1400 N at full extension and 700N at 60° flexion was applied. Results: Sectioning of the AIML produced mechanical variations bellow the two menisci when specimens were at full extension and loaded to 1400N: increasing of mean contact-pressure (delta 0.4+/-0.2MPa, + 15% variation p=0.008) and maximum contact-pressure (delta 1.50+/-0.8MPa, 15% variation p<0.0001), decreasing of tibio-femoral contact area (delta 71+/-51mm2,-15% variation p<0.0001) and PCOA (delta 2.1+/0.8mm). At 60° flexion, significant differences regarding lateral meniscus mechanical parameters was observed before and after AIML resection : mean contact pressure increasing (delta 0.06+/-0.1MPa, +21% variation p=0.001), maximal contact-pressure increasing (delta 0.17+/-0.9MPa, +28% variation p=0.001), mean contact area decreasing (delta 1.84+/-8mm2 4% variation p=0.3), PCOA displacement to the joint-center (mean displacement 0.6+/-0.5mm). Conclusion: The section of the intermeniscal ligament leads to substantial changes in knee's biomechanics, increasing femoro-tibial contact pressures, decreasing contact areas and finally moving force center of application which becomes more central inside of the joint.