The Effect of Modular Dual Mobility Design on the Dislocation Resistance of a Primary Total Hip

Date of Award

8-2018

Document Type

Masters Thesis

Degree Name

M.S.

Organizational Unit

Daniel Felix Ritchie School of Engineering and Computer Science, Mechanical and Materials Engineering

First Advisor

Paul J. Rullkoetter

Keywords

Total hip arthroplasty, Dislocation, Mechanical engineering

Abstract

Total hip arthroplasty (THA) is a widely successful procedure in which the diseased proximal femoral and acetabular bones are replaced with an artificial prosthesis. While THA is extremely successful, revision surgery due to dislocation is still a concern which affects the patient, surgeon, and health care system. Resistance to dislocation remains a primary design consideration when developing new total hip arthroplasty prosthesis.

The present study uses finite element modeling, musculoskeletal modeling and capsular representation to perform an analysis of the dislocation resistance of multiple dual mobility prosthesis designs. Twelve design combinations were tested in a patient driven, posterior dislocation event, and their range of motion at impingement, range of motion at dislocation, peak resistive moment, and energy to dislocate were calculated. These values were input into a dislocation resistance index equation and compared to a neutral acetabular liner with a Ø40mm femoral head to distinguish between designs.

Three design combinations were found to have a higher resistance to a posterior dislocation event. A Ø41.775mm polyethylene mobile bearing with 1mm of medialization, a Ø41.775mm polyethylene mobile bearing with no medialization, and a Ø40.4mm polyethylene mobile bearing with no medialization, all combined with a half-lipped metal liner. While consideration of other events as well as model validation with cadaveric experiments is needed, all three designs performed better than the baseline comparator device and show promise as clinical design possibilities that reduce the likelihood of posterior dislocation.

Publication Statement

Copyright is held by the author. Permanently suppressed.

Rights Holder

Ryan C. Keefer

Provenance

Received from author

File Format

application/pdf

Language

en

File Size

58 pgs

Discipline

Mechanical engineering, Biomechanics

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