Quantifying the kinematics of natural and prosthetic knee flexion

A new method has been developed for quantifying knee kinematics during flexion. This method was used to measure knee kinematics from lateral radiographs taken at different angles of flexion with the two femoral condyles superimposed in each image, thus standardizing the plane of flexion-extension. When applied to the radiographs of five healthy male volunteers (age range 21-26 years), it showed that flexion was accompanied by translation between the articular surfaces. Knee kinematics were also measured in five patients after total knee replacement (TKR) surgery with a Kinemax(TM) Modular Total Knee prosthesis (Howmedica, Warsaw, Indiana). In the TKR patients, a translation was detected in three out of the five patents. This indicates that the prothesis is capable of restoring normal kinematics, but does not always do so. Copyright (C) 1996 Elsevier Science Ltd for IPEMB.