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Indian Orthopaedic Association 57th Annual Conference 2012
[ 16 January 2013 ]

International Revision Hip Arthroplasty Symposium November 2012
[ 30 November 2012 ]

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Tim Board
[ 30 August 2013 ]

Which factors determine the wear rate of large-diameter metal-on-metal hip replacements? Multivariate analysis of two hundred and seventy-six components.
[ 12 July 2013 ]

Medical management of osteonecrosis of the hip: a review
[ 12 July 2013 ]

Total hip replacement

It is generally acknowledged that the results of total hip replacement both functionally and in terms of longevity are very good.  Most patients have resolution of pain or substantial improvement of pain and most patients get back to day to day activities.  Range of movement and function tend to be improved.  Functional results are maintained over time.

In terms of how long joint replacement lasts, one method of measure this is by so-called survivorship analysis.  This is a mathematical method whereby one plots years against the 'x' axis and then looks are the number of failures that had occurred during a certain period.  Therefore we can estimate what is the probability or chance of a hip or knee replacement lasting 10 years, 15 years, 20 years etc and one can apply various other statistical techniques to look at the so-called 95 per cent confidence intervals, ie high degree of confidence that those figures are applicable to the vast majority of patients.  This is a method which has been used in research papers and also in what is called Registry Information.

In Sweden they set up a National Joint Registry in 1976 and various other countries including Norway, Denmark, Finland, Australia and more recently United Kingdom have set up similar records.  The National Joint Registry is a process whereby all operations are invited to be recorded from a country and therefore may be more representative of what actually happens compared to individual surgeons from various expert centres and therefore are looked at quite carefully by the Orthopaedic profession and increasingly from patients.

These Registries can be accessed:

National Joint Registry:  www.njrcentre.org.uk

Swedish National Hip Arthroplasty Register:  www.jru.orthop.gu.se

Swedish Knee Arthroplasty Register:  www.ort.lu.se/knee

Finnish Arthroplasty Register: www.nam.fi/English/publications/medicaldevices.html

Australian National Joint Replacement Registry: www.dmac.Adelaide.edi.au/aoanjrr

American Academy of Orthopaedic Surgeons:  www.aaos.org

New Zealand National Joint Register:  www.cdhb.govt.nz/NJR

The Registries have shown that the general results of joint replacement surgery have increased over time, ie in more recent periods the chances of a joint replacement lasting more than 10 years have increase and this is probably a reflection on better selection of implants and a better take up of surgical techniques.  In broad terms the chances of a hip replacement lasting 10 years is in the region of 95 per cent and the results of a total knee replacement are similar.  In terms of 20 years the figures are not quite so robust but in the region of about 80 per cent for hip and knee.  By visiting the various web sites you will be able to see how different prostheses, in some cases different units and a whole host of other combinations can affect how well implants last. 


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