Journal of Orthopaedic Research

Savio L-Y. Woo Ph.D., J. Marcus Hollis, Ph.D., Douglas J. Adams, M.S. Roger M. Lyon, M.D., Shinro Takai, M.D.


The structural properties of 27 pairs of human cadaver knees were evaluated. Specimens were equally divided into three groups of nine pairs each based on age: younger (22 to 35 years), middle (40 to 50 years), and older (60 to 97 years). Anterior-posterior displacement tests with the intact knee revealed a significant effect of knee flexion angle, but not of specimen age. Tensile tests of the femur - ACL - tibia complex were performed at 30* of knee flexion with the ACL aligned vertically along the direction of applied tensile load. One knee from each pair was oriented anatomically (anatomical orientation), and the contralateral knee was oriented with the tibia aligned vertically (tibial orientation). Structural properties of the femur - ACL - tibia complex, as represented by the linear stiffness, ultimate load, and energy absorbed, were found to decrease significantly with specimen age and were also found to have higher values in specimens tested in the anatomical orientation. In the younger specimens, linear stiffness (242 ± 28 N/mm) and ultimate load (2160 ± 157 N) values found when the femur - ACL - tibia complex was tested in the anatonical orientation were higher than those previously reported in the literature. These values provide new baseline data for the design and selection of grafts for ACL replacement in an attempt to reproduce normal knee kinematics.