Comparison of finite helical axes of normal and anatomically designed prosthetic knees.
Biomechanics
Kinematics
Total knee arthroplasty
Journal
Clinical biomechanics (Bristol, Avon)
ISSN: 1879-1271
Titre abrégé: Clin Biomech (Bristol, Avon)
Pays: England
ID NLM: 8611877
Informations de publication
Date de publication:
05 2019
05 2019
Historique:
received:
27
04
2018
revised:
01
03
2019
accepted:
29
03
2019
pubmed:
16
4
2019
medline:
7
5
2020
entrez:
16
4
2019
Statut:
ppublish
Résumé
Describing three-dimensional joint motion using the finite helical axis has an advantage in understanding unknown coupling motion in prosthetic knee joints. We aimed to examine the differences in the orientations of finite helical axis of normal and anatomically designed cruciate-retaining and posterior-stabilized prosthetic knees after total knee arthroplasty. Ten normal, 40 cruciate-retaining prosthetic knees of 33 patients and 19 posterior-stabilized prosthetic knees of 14 patients enabling to flex > 120° were analyzed during a squatting motion with deep knee bending. The motion was recorded by a fluoroscopic imaging system, and the pose of the bone and prostheses were determined by an image registration technique. The finite helical axes were calculated using 30° window. The finite helical axis in the early flexion phase of the normal knees had a greater inferior inclination (mean - 19.0° (SD 7.2°)) than those of the cruciate-retaining (mean - 1.7 (SD 5.0°)) and posterior-stabilized (mean - 2.9° (SD 5.5°)) prosthetic knees (p < 0.001), and became almost horizontal and constant in the mid to deep flexion phases. In contrast, the cruciate-retaining and posterior-stabilized prosthetic knees demonstrated slightly inclined and almost constant vertical angles throughout the all phases. These results demonstrate that, in the normal knee, a clear coupling motion occurs during the early flexion phase. For the cruciate-retaining and posterior-stabilized prosthetic knees, an unclear coupling motion exists during all phases. These results suggest that the physiological motion is not possible to reproduce using shape-guided motion only even in an anatomically designed prosthetic knee.
Sections du résumé
BACKGROUND
Describing three-dimensional joint motion using the finite helical axis has an advantage in understanding unknown coupling motion in prosthetic knee joints. We aimed to examine the differences in the orientations of finite helical axis of normal and anatomically designed cruciate-retaining and posterior-stabilized prosthetic knees after total knee arthroplasty.
METHODS
Ten normal, 40 cruciate-retaining prosthetic knees of 33 patients and 19 posterior-stabilized prosthetic knees of 14 patients enabling to flex > 120° were analyzed during a squatting motion with deep knee bending. The motion was recorded by a fluoroscopic imaging system, and the pose of the bone and prostheses were determined by an image registration technique. The finite helical axes were calculated using 30° window.
FINDINGS
The finite helical axis in the early flexion phase of the normal knees had a greater inferior inclination (mean - 19.0° (SD 7.2°)) than those of the cruciate-retaining (mean - 1.7 (SD 5.0°)) and posterior-stabilized (mean - 2.9° (SD 5.5°)) prosthetic knees (p < 0.001), and became almost horizontal and constant in the mid to deep flexion phases. In contrast, the cruciate-retaining and posterior-stabilized prosthetic knees demonstrated slightly inclined and almost constant vertical angles throughout the all phases.
INTERPRETATION
These results demonstrate that, in the normal knee, a clear coupling motion occurs during the early flexion phase. For the cruciate-retaining and posterior-stabilized prosthetic knees, an unclear coupling motion exists during all phases. These results suggest that the physiological motion is not possible to reproduce using shape-guided motion only even in an anatomically designed prosthetic knee.
Identifiants
pubmed: 30986763
pii: S0268-0033(18)30291-2
doi: 10.1016/j.clinbiomech.2019.03.018
pii:
doi:
Types de publication
Comparative Study
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
57-64Informations de copyright
Copyright © 2019 Elsevier Ltd. All rights reserved.