Purpose
In 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.
Methods
This 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.
Results
The 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.
Conclusions
Kinematics 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.
[Purpose] The purpose of this study was to determine the normal range of the side-to-side
difference in three dimensional knee kinematics measured by the point cluster technique
(PCT). [Subjects] The subjects were twenty-one healthy normal volunteers without knee pain
or an episode of injury to the legs. [Methods] The subjects were tested bilaterally at a
self-selected normal walking speed and six degrees of freedom knee kinematics were
measured using the PCT, and the 95% confidence intervals of the average side-to-side
differences in flexion-extension (FE), adduction-abduction (AA), internal-external (IE)
rotation, and anterior-posterior (AP), medial-lateral (ML), superior-inferior (SI)
translation in each stage of the gait cycle were determined. [Results] The average
side-to-side differences and their 95% confidence intervals in rotation/translation in
each stage of the gait cycle were determined. The side-to-side differences in AA rotation
and AP translation of the tibia were significantly larger in the swing phase than in the
stance phase. [Conclusion] The side-to-side differences in AA rotation and AP translation
were highly dependent on the stage of the gait cycle. Therefore, the normal ranges of the
side-to-side differences in knee kinematics in each stage of the gait cycle, in particular
AA rotation and AP translation of the tibia, is useful information for evaluating knee
kinematics during walking.
Objectives: To investigate the effects of pelvic and trunk lateral tilt-focused landing instructions on the knee abduction moment during the single-leg drop vertical jump task.
Asymmetry in knee extensor moment during double-leg squatting was observed after anterior cruciate ligament reconstruction, even after the completion of the rehabilitation program for return to sports. The purpose of this study was to clarify the association between asymmetry in the knee extensor moment and pelvic rotation angle during double-leg squatting after anterior cruciate ligament reconstruction. Twenty-four participants performed double-leg squatting. Kinetics and kinematics during squatting were analyzed using a 3-dimensional motion analysis system with 2 force plates. The limb symmetry index of knee extensor moment was predicted by the pelvic rotation angle (R2 = .376, P = .001). In addition, the pelvic rotation and the limb symmetry index of the vertical ground reaction force independently explained the limb symmetry index of the knee extensor moment (R2 = .635, P < .001, β of pelvic rotation = −0.489, β of vertical ground reaction force = 0.524). Pelvic rotation toward the involved limb was associated with a smaller knee extensor moment in the involved limb than in the uninvolved limb. The assessment of pelvic rotation would be useful for partially predicting asymmetry in the knee extensor moment during double-leg squatting. Minimizing pelvic rotation may improve the asymmetry in the knee extensor moment during double-leg squatting after anterior cruciate ligament reconstruction.
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