The femoral stem pump in cemented hip arthroplasty: an in vitro model

G. E. Bartlett, D. J. Beard, D. W. Murray, H. S. Gill

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The presence of an intra-articular pump has been proposed as a central mechanism in the process of osteolysis and aseptic loosening of hip arthroplasty. It is not known if this pump exists and its mechanism remains uncharacterised. This study describes a new in vitro model of a cemented femoral stem in which cement/stem interface fluid pressures can be reliably measured under dynamic loads simulating stair climbing. A stem pump mechanism was found that generates both positive and negative clinically significant pressures (mean pressure ranges 5000-17,000 Pa). The timing of pressure peaks on the anterior and posterior aspects of the stem were in anti-phase, giving rise to oscillatory pressure gradients and potentially generating oscillatory fluid flows during the simulated physiological load cycle. The pump mechanism was shown to occur at the interface of a newly implanted polished double-tapered stem and emphasizes the importance of a complete mantle to protect the femoral bone from the raised fluid pressures.
Original languageEnglish
Pages (from-to)1042-1048
Number of pages7
JournalMedical Engineering & Physics
Volume30
Issue number8
DOIs
Publication statusPublished - 2008

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Arthroplasty
Thigh
Hip
Pumps
Pressure
Stairs
Fluids
Dynamic loads
Osteolysis
Pressure gradient
Flow of fluids
Bone
Cements
In Vitro Techniques
Joints
Bone and Bones

Cite this

The femoral stem pump in cemented hip arthroplasty: an in vitro model. / Bartlett, G. E.; Beard, D. J.; Murray, D. W.; Gill, H. S.

In: Medical Engineering & Physics, Vol. 30, No. 8, 2008, p. 1042-1048.

Research output: Contribution to journalArticle

Bartlett, G. E. ; Beard, D. J. ; Murray, D. W. ; Gill, H. S. / The femoral stem pump in cemented hip arthroplasty: an in vitro model. In: Medical Engineering & Physics. 2008 ; Vol. 30, No. 8. pp. 1042-1048.
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