TY - JOUR
T1 - Acetabular Cups in 60 mm Metal-on-metal bearings subjected to dynamic edge-loading with 70° Peak-Inclination in 10-Million cycle simulator study
AU - Clarke, Ian C.
AU - Halim, Thomas
AU - Smith, Evert J.
AU - Donaldson, Thomas K.
N1 - Publisher Copyright:
© 2018 by the authors.
PY - 2017/12/21
Y1 - 2017/12/21
N2 - Wear simulation of total-hip arthroplasty (THA) involves hip biomechanics, tribology, bearing designs and cup wear-patterns. This is the first demonstration of cup edge-loading using the "Inverted-cup" test mode. Benefits included, (i) clinically relevant wear-patterns, and (ii) cup inclinations varying from ideal to edge-loaded during each 1-s simulator cycle. The 60 mm head and cup bearings in metal-on-metal (MOM) hip joints showed run-in and steady-state wear phases to 10-million cycles (Mc). MOM edge-wear was not unduly high at 1.7 mm3/Mc overall, this 3-fold higher than 60 mm MOM study without edge-loading. One MOM outlier averaged 2.7 mm3/Mc, this representing the break-away wear (BAW) phenomena. A surprising result was that cups contributed 75-93% of total wear. The most disturbing conclusion from review of laboratory studies was that MOM wear-rates varied 1 to > 30 mm3/Mc for reasons not understood. These data suggested a new hypothesis, that MOM bearings were very sensitive to external stimuli, be they simulator artifact or patient related.
AB - Wear simulation of total-hip arthroplasty (THA) involves hip biomechanics, tribology, bearing designs and cup wear-patterns. This is the first demonstration of cup edge-loading using the "Inverted-cup" test mode. Benefits included, (i) clinically relevant wear-patterns, and (ii) cup inclinations varying from ideal to edge-loaded during each 1-s simulator cycle. The 60 mm head and cup bearings in metal-on-metal (MOM) hip joints showed run-in and steady-state wear phases to 10-million cycles (Mc). MOM edge-wear was not unduly high at 1.7 mm3/Mc overall, this 3-fold higher than 60 mm MOM study without edge-loading. One MOM outlier averaged 2.7 mm3/Mc, this representing the break-away wear (BAW) phenomena. A surprising result was that cups contributed 75-93% of total wear. The most disturbing conclusion from review of laboratory studies was that MOM wear-rates varied 1 to > 30 mm3/Mc for reasons not understood. These data suggested a new hypothesis, that MOM bearings were very sensitive to external stimuli, be they simulator artifact or patient related.
KW - 3rd-body wear
KW - CoCr
KW - Hip-joint bearings
KW - Serum lubricant
KW - Simulator
UR - http://www.scopus.com/inward/record.url?scp=85041193470&partnerID=8YFLogxK
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U2 - 10.3390/lubricants6010001
DO - 10.3390/lubricants6010001
M3 - Article
SN - 2075-4442
VL - 6
JO - Lubricants
JF - Lubricants
IS - 1
M1 - 1
ER -