The design of the acetabular component and size of the femoral head influence the risk of revision following 34 721 single-brand cemented hip replacements

A retrospective cohort study of medium-term data from a National Joint Registry

S. S. Jameson, P. N. Baker, J. Mason, P. J. Gregg, N. Brewster, D. J. Deehan, M. R. Reed

Abstract

Despite excellent results, the use of cemented total hip replacement (THR) is declining. This retrospective cohort study records survival time to revision following primary cemented THR using the most common combination of components that accounted for almost a quarter of all cemented THRs, exploring risk factors independently associated with failure. All patients with osteoarthritis who had an Exeter V40/Contemporary THR (Stryker) implanted before 31 December 2010 and recorded in the National Joint Registry for England and Wales were included in the analysis. Cox’s proportional hazard models were used to analyse the extent to which risk of revision was related to patient, surgeon and implant covariates, with a significance threshold of p < 0.01. A total of 34 721 THRs were included in the study. The overall seven-year rate of revision for any reason was 1.70% (99% confidence interval (CI) 1.28 to 2.12). In the final adjusted model the risk of revision was significantly higher in THRs with the Contemporary hooded component (hazard ratio (HR) 1.88, p < 0.001) than with the flanged version, and in smaller head sizes (< 28 mm) compared with 28 mm diameter heads (HR 1.50, p = 0.005). The seven-year revision rate was 1.16% (99% CI 0.69 to 1.63) with a 28 mm diameter head and flanged component. The overall risk of revision was independent of age, gender, American Society of Anesthesiologists grade, body mass index, surgeon volume, surgical approach, brand of cement/presence of antibiotic, femoral head material (stainless steel/alumina) and stem taper size/offset. However, the risk of revision for dislocation was significantly higher with a ‘plus’ offset head (HR 2.05, p = 0.003) and a hooded acetabular component (HR 2.34, p < 0.001).

In summary, we found that there were significant differences in failure between different designs of acetabular component and sizes of femoral head after adjustment for a range of covariates.

Footnotes

  • The authors would like to thank the patients and staff of all the hospitals in England and Wales who have contributed data to the National Joint Registry. We are grateful to the Healthcare Quality Improvement Partnership (HQIP), the NJR steering committee and the staff at the NJR centre for facilitating this work.

    The National Joint Registry for England and Wales is funded through a levy raised on the sale of hip and knee replacement implants. The cost of the levy is set by the NJR Steering Committee. The NJR Steering Committee is responsible for data collection. This work was funded by a fellowship from the National Joint Registry.

    The authors have conformed to the NJR’s standard protocol for data access and publication. The views expressed represent those of the authors and do not necessarily reflect those of the National Joint Register Steering committee or the Health Quality Improvement Partnership (HQIP), who do not vouch for how the information is presented.

    No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

  • Supplementary material. An appendix giving further details of the reliability assessment of the statistical models, two tables detailing the simple and multiple variable Cox regressions of independent predictors of revision for i) all revisions and ii) revision for dislocation, and a table detailing the one-, three-, five- and seven-year rates of revision by head size and acetabular component design, are available with the electronic version of this article on our website www.bjj.boneandjoint.org.uk

  • Received May 9, 2012.
  • Accepted August 9, 2012.
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