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Kevin Garrison
09-13-1995, 08:34 PM
ORIGINAL QUESTION:

I was interested in finding more information on current trends in materials
and design of total joints (hip, knee). Specifically, I read an article by
D. Dowson (1990) that proposed a "cushion" type joint that could come
closer in reproducing the elastohydrodynamic mode of lubrication that
occurs in normal synovial joints. Current designs rely on boundry
lubrication alone which affords higher levels of friction resulting in
premature wear and loosening of the prosthesis. I found the ideas very
interesting but did not know if further research had produced any tangible
results.

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SUMMARY OF RESPONSES:

Date: Thu, 31 Aug 1995 20:17:21 +0000
From: clfr50 To: alhkg@ttuhsc.edu
Subject: Re: biomaterials
X-Sun-Charset: US-ASCII


->TI: FRICTIONAL CHARACTERIZATION OF EXPLANTED CHARNLEY HIP PROSTHESES
AU: HALL_RM, UNSWORTH_A, WROBLEWSKI_BM, BURGESS_IC NA: UNIV DURHAM,CTR
BIOMED ENGN,DURHAM DH1 3HP,ENGLAND
UNIV DURHAM,CTR BIOMED ENGN,DURHAM DH1 3HP,ENGLAND WRIGHTINGTON HOSP,CTR
HIP SURG,WIGAN,ENGLAND JN: WEAR, 1994, Vol.175, No.1-2, pp.159-166 IS:
0043-1648
AB: The frictional resistances of 54 explanted and 5 new Charnley hip
prostheses were measured using one of two Durham hip function simulators.
The friction factor f was measured in both dry and lubricated environments
up to a viscosity eta of approximately 0.1 Pa s. The friction factor values
for the new prostheses were found to be 0.11 (+/-0.025) and 0.04 (+/-0.01)
for dry and lubricated (eta=0.01 Pa s) regimes respectively. The
distributions of f for the new prostheses were found to be approximately
Gaussian. However, the distributions for the explanted prostheses were
skewed, with most retaining friction values similar to those of new
prostheses, but a significant proportion exhibiting increased frictional
resistance. For dry regimes 30% of the prostheses showed values of f in
excess of 0.16, while for lubricated regimes (eta=0.01 Pa s) 39% showed
values of f greater than 0.07. All the joints indicated a mixed lubrication
regime when analysed in terms of a Stribeck plot. A weak negative
correlation (P