Tibiofemoral kinematic analysis of knee flexion for a medial pivot knee

Abstract

The performance of total knee arthroplasty in deeply flexed postures is of increasing concern as the procedure is performed on younger, more physically active and more culturally diverse populations. Several implant design factors, including tibiofemoral conformity, tibial slope and posterior condylar geometry have been shown directly to affect deep flexion performance. The goal of this study was to evaluate the kinematics of a fixed-bearing, asymmetric, medial rotation arthroplasty design in moderate and deep flexion. Thirteen study participants (15 knees) with a medial rotation knee arthroplasty were observed performing a weight-bearing lunge activity to maximum comfortable flexion and kneeling on a padded bench from 90 degrees to maximum comfortable flexion using lateral fluoroscopy. Subjects averaged 74 years of age and nine were female. At maximum weight-bearing flexion, the knees exhibited 115 degrees of implant flexion (102 degrees-125 degrees) and 7 degrees (-3 degrees to 12 degrees) of tibial internal rotation. The medial and lateral condylar translated posteriorly by 2 and 5 mm, respectively. At maximum kneeling flexion, the knees exhibited 119 degrees of implant flexion (101 degrees-139 degrees ) and 5 degrees (-2 degrees to 14 degrees) of tibial internal rotation. The lateral condyle translated posteriorly by 11 mm. The medial rotation knee exhibited motion patterns similar to those observed in the normal knee, but less tibial rotation. The medially conforming articulation beneficially controls femoral AP position in deep flexion, in patients who require such motion as part of their lifestyle.

Effect of Posterior Femoral Condylar Offset and Posterior Tibial Slope on Maximal Flexion Angle of the Knee in Posterior Cruciate Ligament Sacrificing Total Knee Arthroplasty

“…ROM after TKA using a medial pivot knee system designed based on the concept of medial-pivoting of the knee during flexion21,22) has been documented in a variety of domestic and international research23-29). The mean maximal flexion angle of 118.44° that was obtained in our patients is comparable to the values reported in those studies.…”

Knee Arthroplasty With a Medially Conforming Ball-and-Socket Tibiofemoral Articulation Provides Better Function

“…Consequently, this provides stability throughout the ROM to prevent AP translation. On the lateral side, there is a lack of congruence allowing lateral femoral rollback in a manner close to the normal kinematic profile of the knee [26]. This specific design feature may confer the additional functional benefits seen in the MRK group.…”

Range of motion predictability after total knee arthroplasty with medial pivot prosthesis

“…Several authors analyzed ROM after arthroplasty with the use of the medial-pivot design and found a relationship between preoperative ROM and that obtained after surgery 4, 5, 23, 25, 26, 27. Shakespeare et al 28 compared 261 knees undergoing arthroplasty with medial-pivot prosthesis with 913 cases in which TKA with PCL sacrifice was performed.…”