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Historical
Metal on Metal Joints
Lessons Learned from
Historical Metal on Metal THRs
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Seven surgeons at
Birmingham's Royal Orthopaedic Hospital carried out metal on
metal total hip replacements (THRs) of McKee, Ring and Stanmore
types between 1966 and 1987.
It could not go
unnoticed in our clinical follow up practice that these
patient's hips were performing exceptionally well and in
particular there was a notable absence of osteolysis associated
with the majority of these implants. Young active patients whose
implants remained secure had no osteolysis. |

McKee |

Ring |

Stanmore |
In patients whose implants
loosened, however, cement debris was generated and in these, hips'
cement debris did cause osteolysis just as badly as polyethylene debris.
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McKee-Farrar, loose cup at 20
yrs.
Severe pelvic osteolysis.
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Same case at
revision surgery.
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20 yr + F.U. Ring Metal
on Metal THR |
The most interesting
patients were those who had the uncemented metal on metal Ring
THR. We have never seen a case of osteolysis associated with
this implant. As can be seen, many of these implants were
inserted in positions that would not be accepted today but the
key feature of note is that although these implants have been in
situ for a minimum of twenty years, no patient has osteolysis.
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This is all the more
remarkable because these smooth chrome cobalt implants had soft
tissue at the bone implant. It is regular experience to see
patients with an open interface develop osteolysis as a result
of polyethylene debris ingress, but despite the open interfaces
present on all of these radiographs not a single patient
developed osteolysis. |
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Open interfaces Ring femoral
and
acetabular components |
This led us to the
conclusion that in the absence of other debris, a metal on metal bearing
does not cause osteolysis over a twenty year period.
Back to History of Hip Resurfacing Menu
12/31/2005
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