Influence of stem geometry on the stability of polished tapered cemented femoral stems

S. Glyn-Jones, H. S. Gill, D. J. Beard, P. McLardy-Smith, D. W. Murray

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Polished, tapered stems are now widely used for cemented total hip replacement and many such designs have been introduced. However, a change in stem geometry may have a profound influence on stability. Stems with a wide, rectangular proximal section may be more stable than those which are narrower proximally. We examined the influence of proximal geometry on stability by comparing the two-year migration of the Exeter stem with a more recent design, the CPS-Plus, which has a wider shoulder and a more rectangular cross-section. The hypothesis was that these design features would increase rotational stability.Both stems subsided approximately 1 mm relative to the femur during the first two years after implantation. The Exeter stem was found to rotate into valgus (mean 0.2 degrees , sd 0.42 degrees ) and internally rotate (mean 1.28 degrees , sd 0.99 degrees ). The CPS-Plus showed no significant valgus rotation (mean 0.07 [correction] degrees, sd 0.29 [correction] degrees ) or internal rotation (mean -0.03 degrees , sd 0.75 degrees ). A wider, more rectangular cross-section improves rotational stability and may have a better long-term outcome.
Original languageEnglish
Pages (from-to)921-927
Number of pages7
JournalJournal of Bone and Joint Surgery - British Volume
Volume87
Issue number7
DOIs
Publication statusPublished - 2005

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