Measurement Of Three-dimensional Knee Joint Kinematics:Techniques And Applications

The kinematic comparison between the native knee and artificial knee is animportant way to understand the joint disease mechanism and assess the clinicaloutcomes. Currently, the accurate measurement of the dynamic knee joint motion inthree dimensions (3D) is still a challenging issue in technique. The kinematic differenceof the knees underwent total knee arthroplasty (TKA) needs to be investigated in clinic.In this study, the X-ray images and optical tracking technique were applied tomeasure the3D kinematics of the in-vivo and in-vitro knees. The joint kinematicsbefore and after the posterior stabilized TKA were measured. The effect of the TKAdesigns to the patellofemoral joint and patellar tendon was investigated.A2D-3D image-model registration technique was applied to reconstruct the3Dmotion of the in-vivo knee joint. An algorithm of2D-3D automatic registration wasdeveloped to enhance the method, which simplified the time-consuming process. Theaccuracy and repeatability were improved. The technique was applied to study thenormal knees during stair ascending and deep flexion and the knees after TKAs.The patient-specific knee model is the basis to study the in-vivo3D knee jointkinematics. Currently, the CT or MRI images can be used to reconstruct3D kneemodels, but with high radiation and cost. In order to overcome the above disadvantages,a statistical deformable model was developed to generate the knee models with boneand cartilage, which was accurate enough to study knee joint kinematics.In vivo studies, the accurate tracking of the knee joint is difficult, and the motion islimited by the X-ray imaging zone. The marker-based optical tracking technique wasused to track the motion of the cadaveric patella in this study. Different types of TKAprosthesis were compared. Due to the capability of tracking large range of motion inspace, the technique was used to measure the knee kinematics and Q angle during squat.In summary, key techniques were presented in this study to measure the kinematicsof the knee joints before and after TKAs. Meanwhile a new method to reconstructpatient-specific knee model was developed. The result has an essential significance inclinic. The techniques can be used to measure the3D kinematics of other human joints.