Kinematics and center of axial rotation during walking after medial pivot type total knee arthroplasty

Kota Miura,Yasumitsu Ohkoshi,Tatsunori Maeda,Ko Suzuki,Sho’Ji Suzuki,Kensaku Kawakami,Takumi Ino,Kengo Ukishiro

doi:10.1186/s40634-020-00286-y

Abstract

PurposeIn recent years, the medial pivot (MP) type total knee arthroplasty (TKA) implant has been developed and marketed for achieving more natural kinematics with MP. However, little is known about the pivot pattern during walking after MP type TKA. This study aimed to determine the kinematics and center of axial rotation during walking after MP type TKA.MethodsThis randomized prospective study enrolled 40 patients with MP type TKA, 20 with cruciate-substituting TKA (MP-CS group), 20 with posterior-stabilized TKA (MP-PS group), and 10 healthy volunteers (control group). The kinematics and center of axial rotation during overground walking were measured by a three-dimensional motion analysis system. The six-degrees-of-freedom kinematics of the knee were calculated by the point cluster method.ResultsThe amount of change in knee flexion in early stance phase was significantly lower in the MP-CS and MP-PS groups than in the control group. The femur showed anterior translation during early stance phase in all three groups. The median center of axial rotation in the transverse plane was predominantly on the lateral side of the knee during stance in all groups.ConclusionsKinematics during gait are thought to be determined by physical posture, the kinetic chain during weight-bearing, and the kinematic features of adjacent structures, such as the behavior of the biarticular muscles. MP-CS and MP-PS did not necessarily induce rotational motion centered on the medial ball-in-socket component during walking; translational and lateral pivoting movements were also observed. Long-term follow-up is needed to monitor for polyethylene wear and implant loosening.

Highlights

Six-degrees-of-freedom (6DOF) kinematics of the knee joint during walking are determined by physical posture, the position of the body’s barycenter, the kinetic chain during weight-bearing, muscle coordination and antagonism, and the kinematic features of adjacent structures, including the behavior of the biarticular muscles [2, 8, 12, 15]
There was no significant difference in preoperative knee flexion angle, bone morphology angle, or clinical outcome between the medial pivot (MP)-CS and MP-PS groups (Table 1)
Walking speeds were significantly lower in the MP-CS and MP-PS groups both pre- and postoperatively compared with the control group (Table 2)

Summary

Introduction

Six-degrees-of-freedom (6DOF) kinematics of the knee joint during walking are determined by physical posture, the position of the body’s barycenter, the kinetic chain during weight-bearing, muscle coordination and antagonism, and the kinematic features of adjacent structures, including the behavior of the biarticular muscles [2, 8, 12, 15]. A fluoroscopic study by Kozanek et al [17] found that lateral pivot occurred during walking in healthy subjects. Koo et al [16] analyzed walking in healthy subjects by using an optical motion capture technique and reported the presence of lateral pivot motion. The findings of these reports are inconsistent with the position of the COR, even in healthy knees. The present study aimed to determine the 6DOF knee kinematics and location of the COR in the transverse plane of the knee during walking in patients with MP type TKA

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