Hip Replacement |
Written by Administrator |
Tuesday, 10 May 2011 22:38 |
Hip replacement remains one of the great successes of modern medicine. It can huge improvement in the quality of life of a patient suffering from hip arthritis. We would expect well over 90% of hips to last more than 10 years and the majority to last 20 to 30 years.
The hip replacement on the left is an Acolade/Trident uncemented hip made by Stryker. It has excellent results and Mr Oakley has been using it for those patients suitable for uncemented hips for 7 years.
In an uncemented hip the bone is cut to provide an interference fit with the prosthesis. Then over about 6 weeks the bone grows onto the special surface and produces a permanant living bond without the need for a "glue " or "cement". This is especially attractive in young active patients but can also have advantages in older patients as well.
Bearing choice is critical for the longlevity of a hip replacement. As wear occurs, the particles generated cause a tissue reaction which over time causes the implant to become loose and bone to be absorbed. The famous Charnley hip replacement had a bearing of metal against ultra high density polyethylene.
The hip replacement on the left has a ceramic bearing which produced the lowest volume of wear products per million cycles of any bearing couple. The Charnley Hip, while being the original gold standard, has now been mostly superseeded. Its principles of being cemented in place by methylmetacralate cement and using a metal on polyethylene bearing are carried over into the Exeter shown on the right. This hip was first designed in 1970 and the best series of results show about 90% survival at up to 30 years. This is the cemented hip that Mr Oakley uses. It is now possible to combine cemented technology with a ceramic bearing. |
Last Updated on Sunday, 29 September 2013 14:05 |