Stem taper mismatch has a critical effect on ceramic head fracture risk in modular hip arthroplasty.

Authors :: Gührs J
Körner M
Bechstedt M
Krull A
Morlock MM
Source :: Clinical biomechanics (Bristol, Avon) [Clin Biomech (Bristol, Avon)] 2017 Jan; Vol. 41, pp. 106-110. Date of Electronic Publication: 2016 Dec 16.
Publication Year :: 2017
Abstract: Background: Modular total hip prostheses with ceramic heads are well established in orthopedic surgery and widely used. With the variety of different manufacturers and available designs, components are at risk for mismatch. Several case studies show the potentially devastating effects of mismatch.<br />Methods: The aim of this study was to investigate the outcome of one arbitrary component mismatch with commercially available components that appear to provide a stable fixation during assembly. A biomechanical in-vitro analysis of fracture strength (n=5) was carried out in accordance with ISO 7206-10. "Type1" Bi-Metric®-stems were mismatched with "V40" Al <subscript>2</subscript> O <subscript>3</subscript> ceramic heads.<br />Findings: Mean fracture strength was reduced to about 50% of the recommended FDA minimum by the mismatch (Mean 23.68kN, SD 2.35kN). A small contact area between head and stem taper was identified as a potential key parameter.<br />Interpretation: Mixing and matching components can put a patient at greater risk for ceramic head fracture and must be avoided.<br /> (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Subjects :: Ceramics
Humans
Risk Factors
Arthroplasty, Replacement, Hip instrumentation
Hip Prosthesis
Prosthesis Design
Prosthesis Failure

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