Anterior cruciate ligament reconstruction and cartilage contact forces-A 3D computational simulation

Background: Clinical outcome studies showed a high incidence of knee osteoarthritis after anterior cruciate ligament reconstruction. Abnormal joint kinematics and loading conditions were assumed as risking factors. However, little is known on cartilage contact forces after the surgery. Methods: A validated computational model was used to simulate anatomic and transtibial single-bundle anterior cruciate ligament reconstructions. Two graft fixation angles (0 degrees and 30 degrees) were simulated for each reconstruction. Biomechanics of the knee was investigated in intact, anterior cruciate ligament deficient and reconstructed conditions when the knee was subjected to 134 N anterior load and 400 N quadriceps load at 0 degrees, 30 degrees, 60 degrees and 90 degrees of flexion. The tibial translation and rotation, graft forces, medial and lateral contact forces were calculated. Findings: When the graft was fixed at 0 degrees, the anatomic reconstruction resulted in slightly larger lateral contact force at 0 degrees compared to the intact knee while the transtibial technique led to higher contact force at both 0 degrees and 30 degrees under the muscle load. When graft was fixed at 30 degrees, the anatomic reconstruction overstrained the knee at 0 degrees with larger contact forces, while the transtibial technique resulted in slightly larger contact forces at 30 degrees. Interpretation: This study suggests that neither the anatomic nor the transtibial reconstruction can consistently restore normal knee biomechanics at different flexion angles. The anatomic reconstruction may better restore anteroposterior stability and contact force with the graft fixed at 0 degrees. The transtibial technique may better restore knee anteroposterior stability and articular contact force with the graft fixed at 30 degrees of flexion. (C) 2015 Elsevier Ltd. All rights reserved.National Institute of Health [R01AR055612]; China Scholarship CouncilSCI(E)EIPubMedARTICLELi.Guoan@mgh.harvard.edu101175-11803