Three‐dimensional motion analysis of the patellar component in total knee arthroplasty by the image matching method using image correlations

Abstract

In total knee arthroplasty (TKA), the patella is significantly associated with range of motion and gait performance. Currently, no highly accurate methods are available that can measure the 3D in vivo behavior of the TKA patellar component, as the component is made of x-ray-permeable ultra-high molecular weight polyethylene. Previously, we developed a computer simulation that matches CT scan and unidirectional radiographic images using image correlations, and applied it to kinematic studies of natural and TKA knees. The examination of the measurement accuracy for the patellar bone of a fresh-frozen pig knee joint yielded a root mean square error of 0.2 mm in translation and 0.2˚in rotation. In this study, we recruited four patients who had a TKA and investigated 3D movements of the patellar component during squatting. We could visualize the patellar component using the position of the holes drilled for the component peg, and estimated and visualized the contact points between the patellar and femoral components. The principles and the utility of the simulation method are reported. This analytical method is useful for evaluating the pathologies and post-surgical conditions of the knee and other joints. Total knee arthroplasty (TKA) is a reliable surgical procedure for reconstructing severely impaired knee joints. TKA can improve pain relief, functional mobility, weight-bearing capability, and patient quality of life.1 The widespread use of TKA promoted studies on TKA kinematics, particularly of the femorotibial joint.2,3 TKA knee kinematics, including range of motion (ROM) and physical performance, are also influenced by the biomechanical properties of the patella. Surgeons sometimes report post-TKA complications involving the patellofemoral articulation, for example, anterior knee pain, patellofemoral impingement and instability.4,5 Therefore, it is important to examine whether the implanted total knee prosthesis is functioning as designed. However, conventional imaging techniques cannot analyze the biomechanical characteristics of the patellofemoral joint accurately enough because of the small volume of patella bone and the overlapping of patellar and femoral silhouettes on scan images. In TKA, the patella is commonly resurfaced, which further reduces its volume, and the radiopaque metal femoral component is often superimposed on the patellar component on 2D images. In addition, the patellar component is made of radiolucent ultra-high molecular weight polyethylene. Therefore, it is impossible to determine radiographically the external contour of the patellar component precisely. Because of these technical limitations, no methods have been established to track the dynamic in vivo trajectory of the patella.Previously, we developed a unique computerassisted image matching procedure to analyze the kinematics of natural and TKA knees by applying an image window-based analytical method to serial unidirectional x-ray scans. [6][7][8][9][10] In this study, we aimed to visualize the patellar component and iden...

A patient-specific model of total knee arthroplasty to estimate patellar strain: A case study

“…The kinematics predictions of the model were in good agreement with current in vivo studies (Ishimaru et al, 2014;Sharma et al, 2012). The predicted and measured quadriceps force, and the patellofemoral and patellar tendon forces were also consistent with reported values (Fitzpatrick et al, 2014b;Frohm et al, 2007;Mason et al, 2008).…”

Finite element modeling of proximal femur with quantifiable weight-bearing area in standing position

“…Daniel et al [23] calculated by formula that the weight-bearing area should be in the area where the top of the femoral head overlaps with the acetabular cartilage surface, and can be affected The calculation method of weight-bearing area of femoral head in standing position mainly refers to the theoretical formula proposed by Genda et al [2], and the 3D reconstruction is realized by the principle of projection transformation and image registration. Ishimaru et al [25] reported simulating X-ray by projection transformation to create virtual radiographic image of 3D knee joint model and registering it with real X-ray film to realize visual reconstruction of polymer polyethylene patellar component and radiographically determine its external contour. Image registration is vital to the accurate construction of weight-bearing area in our modeling process, and obtaining X-ray, CT data of one volunteer in the same body posture is the premise of accurate registration.…”

Kinematic Analysis of Healthy Hips during Weight-Bearing Activities by 3D-to-2D Model-to-Image Registration Technique

“…The 3D positions and orientations of the pelvis and femur in movement cycle were determined by 3D-to-2D model-to-image registration technique using image correlations ( Figure 2 ). The relative geometric relationship between the X-ray source and the projection plane of the flat panel X-ray detector system was determined using a coordinate building frame [ 13 , 14 ]. Each subject was scanned by computed tomography (CT; Aquilion, Toshiba, Tochigi, Japan) with a 512 × 512 image matrix, 0.35 × 0.35 pixel dim, and 1 mm thickness spanning from superior edge of the pelvis to below the knee joint line ( Figure 2(c) ).…”

“…However, external markers attached to the skin could be affected by soft tissue artifacts with substantial errors [ 5 – 7 ]. Previous studies have reported direct measurement of skeletal kinematics from 3D surface models and radiographic image sequences [ 8 – 13 ]. However, no studies have employed 3D-to-2D model-to-image registration technique to analyze in vivo healthy hip kinematics.…”