Advertisement for orthosearch.org.uk
Orthopaedic Proceedings Logo

Receive monthly Table of Contents alerts from Orthopaedic Proceedings

Comprehensive article alerts can be set up and managed through your account settings

View my account settings

Visit Orthopaedic Proceedings at:

Loading...

Loading...

Full Access

General Orthopaedics

Serum Metal Ion Levels in Bilateral and Unilateral Metal on Metal (MoM) Stemmed Hip Arthroplasty - Is There a Significant Difference?

International Society for Technology in Arthroplasty (ISTA)



Abstract

Introduction:

The clinical significance of serum metal ion levels alone in patients with stemmed MoM hip arthroplasty remains uncertain. This study aims to measure the metal ion levels in patients with unilateral and bilateral hip arthroplasty to see whether or not the patients with bilateral hips have higher metal ions.

Patients and Methods

All the patients with bilateral MoM hip arthroplasty were identified from the research database. These patients were then matched with those in a similar age group who had a unilateral hip arthroplasty, but same University of California Los Angeles (UCLA) activity score. The UCLA activity scores along with other hip scores have been previously gathered for all the patients. Both sets of patients then had measurement of serum cobalt and chromium levels. The results were analyzed and compared.

Results:

There were a total of 53 patients with bilateral hips and 53 matched patients with unilateral hips. The average serum Cobalt and Chromium levels were 34 nmol/L (range <10–76) and 23 nmol/L (range <10–104) respectively in the bilateral group; and 14 nmol/L (range <10–45) and 21 nmol/L (range <10–57) in the unilateral group. Given that the MHRA (UK) threshold levels deemed clinically significant are 120 nmol/L and 135 nmol/L for Cobalt and Chromium respectively; the results obtained here are not clinically significant.

Conclusions:

One would normally expect, with mathematical reasoning, a patient with bilateral hip arthroplasty to have higher serum metal ion levels than a patient with unilateral arthroplasty. However, this study goes to show that it is not the case.


*Email: