Kinematics of medial osteoarthritic knees before and after posterior cruciate ligament retaining total knee arthroplasty

Abstract

Total knee arthroplasty (TKA) is a widely accepted surgical procedure for the treatment of patients with end-stage osteoarthritis (OA). However, the function of the knee is not always fully recovered after TKA. We used a dual fluoroscopic imaging system to evaluate the in vivo kinematics of the knee with medial compartment OA before and after a posterior cruciate ligament-retaining TKA (PCR-TKA) during weight-bearing knee flexion, and compared the results to those of normal knees. The OA knees displayed similar internal/external tibial rotation to normal knees. However, the OA knees had less overall posterior femoral translation relative to the tibia between 0 • and 105 • flexion and more varus knee rotation between 0 • and 45 • flexion, than in the normal knees. Additionally, in the OA knees the femur was located more medially than in the normal knees, particularly between 30 • and 60 • flexion. After PCR-TKA, the knee kinematics were not restored to normal. The overall internal tibial rotation and posterior femoral translation between 0 • and 105 • knee flexion were dramatically reduced. Additionally, PCR-TKA introduced an abnormal anterior femoral translation during early knee flexion, and the femur was located lateral to the tibia throughout weight-bearing flexion. The data help understand the biomechanical functions of the knee with medial compartment OA before and after contemporary PCR-TKA. They may also be useful for improvement of future prostheses designs and surgical techniques in treatment of knees with end-stage OA.

Is There a Gold Standard for TKA Tibial Component Rotational Alignment?

“…An increase in anterior femoral translation after TKA has been welldocumented [12,16,45,55], with Cromie et al [16] reporting TKA knees showed a mean of 16.1 mm anterior motion, which overlaps with our findings (Table 2). Studies on tibial internal-external rotation after TKA have reported mixed findings, with some researchers noting decreases [45] and others reporting no change [12].…”

In vivo function of posterior cruciate ligament before and after posterior cruciate ligament-retaining total knee arthroplasty

“…Interestingly, our study found that elongation of PCL bundles in PCL-retaining TKA knees was significantly greater than those of normal and preoperative OA knees during late knee flexion, suggesting the PCL may have become tighter after PCL-retaining TKA at high flexion in this group of patients. Overstretching of the PCL was correlated to the reduced posterior femoral translation (femoral rollback) in the same patient group after PCL-retaining TKA [25]. Reduction of femoral rollback has also been observed in many previous studies of PCL-retaining TKAs [2,23].…”

“…The relative positions of the PCL attachment areas on the tibia and femur were also determined at each flexion angle. To measure PCL kinematics after TKA, the same preoperative knee models were used in to determine PCL kinematics [25].…”

Elongation of the collateral ligaments after cruciate retaining total knee arthroplasty and the maximum flexion of the knee

“…Eleven patients with advanced medial-compartment knee OA were recruited in a previous study for investigation of 6DOF kinematics of the knee before and after CR-TKA (Yue et al, 2011). Patient demography was shown in Table 1.…”

“…The area centroids of the attachment sites were determined on the bony surfaces. Dual fluoroscopic images of each knee were acquired during a weight-bearing single leg lunge from full extension to maximal flexion without altering the orientation of the foot and torso (Yue et al, 2011).…”