The geometric design of a total knee arthroplasty system can cause changes in the wear and fixation of the device, as well as the kinematics of the replaced joint (Nilsonn, et al., 1997). Troubles arise when trying to determine the strain behavior of the collateral ligaments of the knee, due to subject-to-subject variations (Crownshield et al., 1975). This study compared the strain in the collateral ligaments of the knee, before and after a total knee arthroplasty. It is hypothesized that this information can be used to indicate the effects of the TKA on these ligaments. If the strain after a TKA is greater than the normal physiological strain in these ligaments, this may be perceived as a source of discomfort or disfunction for the patient. Such a comparison of strain patterns may be used as a tool in the design of improved total knee arthroplasty system.