当前位置： SCI文献检索 > CLINICAL ORTHOPAEDICS AND RELATED RESEARCH期刊下所有文献 > The effect of geometric variations in posterior-stabilized knee designs on motion characteristics measured in a knee loading machine.

The effect of geometric variations in posterior-stabilized knee designs on motion characteristics measured in a knee loading machine.

Abstract：

BACKGROUND:In different posterior-stabilized (PS) total knees, there are considerable variations in condylar surface radii and cam-post geometry. To what extent these variations affect kinematics is not known. Furthermore, there are no clearly defined ideal kinematics for a total knee. QUESTIONS/PURPOSES:The purposes of this study were to determine (1) what the kinematic differences are caused by geometrical variations between PS total knee designs in use today; and (2) what design characteristics will produce kinematics that closely resemble that of the normal anatomic knee. METHODS:Four current PS designs with different geometries and one experimental asymmetric PS design, with a relatively conforming medial side, were tested in a purpose-built machine. The machine applied combinations of compressive, shear, and torque forces at a sequence of flexion angles to represent a range of everyday activities, consistent with the ASTM standard test for measuring constraint. The femorotibial contact points, the neutral path of motion, and the AP and internal-external laxities were used as the kinematic indicators. RESULTS:The PS designs showed major differences in motion characteristics among themselves and with motion data from anatomic knees determined in a previous study. Abnormalities in the current designs included symmetric mediolateral motion, susceptibility to excessive AP medial laxity, and reduced laxity in high flexion. The asymmetric-guided motion design alleviated some but not all of the abnormalities. CONCLUSIONS:Current PS designs showed kinematic abnormalities to a greater or lesser extent. An asymmetric design may provide a path to achieving a closer match to anatomic kinematics. CLINICAL RELEVANCE:One criterion for the evaluation of PS total knees is how closely the kinematics of the prosthesis resemble that of the anatomic knee, because this is likely to affect the quality of function.

journal_name

Clin Orthop Relat Res

journal_title

Clinical orthopaedics and related research

authors

Walker PS,Lowry MT,Kumar A

doi

10.1007/s11999-013-3088-2

subject

Has Abstract

pub_date

2014-01-01 00:00:00

pages

238-47

issue

eissn

0009-921X

issn

1528-1132

journal_volume

472

pub_type

杂志文章

在线工具

The effect of geometric variations in posterior-stabilized knee designs on motion characteristics measured in a knee loading machine.