Magnetic resonance imaging of in vivo kinematics after total knee arthroplasty

Abstract

Purpose:To improve the quality of magnetic resonance imaging (MRI) on knees after total knee arthroplasty (TKA) by minimizing image artifacts caused by metallic implants, and to establish a method determining in vivo kinematics of TKA knees using MRI. Materials and Methods:Two knee implants made of cobaltchrome and oxidized zirconium were tested with different pulse sequences and imaging parameters. Then, in vivo kinematic MRI was performed on five well-functioning TKAs under simulated weight-bearing conditions. Kinematic measurements were made and a linear correlation test was run between the tibio-and patellofemoral measurements. Results:The best images with minimum metallic artifacts were observed using oxidized zirconium implants, a fast spin echo sequence (FSE), thin slice thickness, and high readout gradient. TKA kinematics exhibited a large deviation from the normal kinematics and considerable patientto-patient variability. However, significant linear correlations between tibiofemoral and patellofemoral kinematics were observed (R ϭ -0.96, 0.92, 0.88). Conclusion:Metallic artifacts due to orthopedic implants can be reduced in MR images for some materials, appropriate pulse sequence, and imaging parameters selection, enabling MR quantification of knee kinematics. Tibiofemoral kinematics appears to affect patellofemoral position after total knee arthroplasty.

A new in vivo technique for determination of femoro-tibial and femoro-patellar 3D kinematics in total knee arthroplasty

“…Another technique recently applied have been highfield MRI (Lee et al, 2005;Sheehan et al, 1999). However, due to the construction of the MR scanner, the assessment can only be performed in knee flexion angles of less than 601, although it has been demonstrated that after TKA significant alterations in patellar kinematics occur especially in greater flexion angles (Tanzer et al, 2001).…”

“…Due to the 2D nature of fluoroscopy, motions perpendicular to the fluoroscopic images are difficult to evaluate reliable. Therefore the femoro-patellar 3D kinematics and its relationship to changes in femoro-tibial motion patterns remained less clear (Lee et al, 2005). However, patello-femoral disorders due to changes of the patellar kinematics are responsible for up to 50% of all revisions after total knee replacement Lee et al, 1997).…”

In vivopatellar kinematics during total knee arthroplasty

“…In vivo studies have been conducted on the replaced joint, using MRI [33,34] and fluoroscopy [35,36], but none of them has looked at changes due to arthroplasty, and only sagittal-plane patellar kinematics are available when using fluoroscopy. There is, therefore, a lack of in vivo data regarding intraoperative patellar kinematics and the changes caused by arthroplasty.…”

Contemporary femoral designs in total knee arthroplasty: effects on the patello-femoral congruence

“…Maltracking may result from excessive or unbalanced tension in the surrounding soft tissues during knee flexion, so our radiographic measurements do not reflect patello-femoral congruence during ROM. A CT scan or MRI in vivo assessment might be necessary [18,40,41]. Anyway, Varadarajan et al [42] demonstrated that, even with a correct external rotation, the trochlear groove in current TKA designs only partially restores normal anatomy.…”