Title

Mechanics of hip dysplasia reductions in infants using the Pavlik harness: A physics-based computational model

Authors

Authors

O. J. Ardila; E. A. Divo; F. A. Moslehy; G. T. Rab; A. J. Kassab;C. T. Price

Comments

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Abbreviated Journal Title

J. Biomech.

Keywords

Pavlik harness; Hip dysplasia; Dynamical analysis; Passive reduction; Non-linear muscle model; CONGENITAL DISLOCATION; ULTRASOUND; Biophysics; Engineering, Biomedical

Abstract

Biomechanical factors influencing the reduction of dislocated hips with the Pavlik harness in patients of Developmental Dysplasia of the Hip (DDH) were studied using a three-dimensional computer model simulating hip reduction dynamics in (1) sublwcated and (2) fully dislocated hip joints. Five hip adductor muscles were identified as key mediators of DDH prognosis, and the non-dimensional force contribution of each in the direction necessary to achieve concentric hip reductions was determined. Results point to the adductor muscles as mediators of subluxated hip reductions, as their mechanical action is a function of the degree of hip dislocation. For subluxated hips in abduction and flexion, the Pectineus, Adductor Brevis, Adductor Longus, and proximal Adductor Magnus contribute positively to reduction, while the rest of the Adductor Magnus contributes negatively. In full dislocations all muscles contribute detrimentally to reduction, elucidating the need for traction to reduce Graf IV type dislocations. Reduction of dysplastic hips was found to occur in two distinct phases: (a) release phase and (b) reduction phase. cp (C) 2013 Elsevier Ltd. All rights reserved.

Journal Title

Journal of Biomechanics

Volume

46

Issue/Number

9

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

1501

Last Page

1507

WOS Identifier

WOS:000320827700004

ISSN

0021-9290

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