An analysis of choice: a case study on hip prostheses

Davies, Charlotte (2011) An analysis of choice: a case study on hip prostheses. Doctoral thesis, University of East Anglia.

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Total hip replacement (THR) surgery is a highly successful procedure offering relief of
chronic pain and improving physical functioning. Given an ageing population, there is an
ever increasing demand for THR, and an increasing need to establish its cost-effectiveness.
This thesis explores two aspects of choice between the alternative prostheses: how choices
should be made, and what choices are actually made.
On the former, a key indicator is the long-term prosthesis survival rate. However, when
choosing between prostheses, there is often insufficient evidence on long-term survival. The
National Joint Registry (NJR) is an invaluable emerging source of information on this count.
Using its Annual Reports, I identify, for example, that the use of cementless prostheses has
grown rapidly, despite their performance in terms of early revision being inferior to the
traditional cemented types.
However, the NJR was only introduced in 2003, and cannot yet provide information on
longer term prosthesis survival. Previous research has attempted to predict long-term
survival by forecasting from short-term data. I assess this approach by revisiting a wellknown
case-study, examining how well estimated survival curves predict what actually
happened. I find that the predictions are very inaccurate, underlining the future value of the
NJR as it accumulates more evidence.
On the latter, I employ raw NJR data to examine the actual choices between prostheses made
by hospitals. Patients’ characteristics explain little variation between hospitals with hospital
characteristics appearing more important. I consider how choice might be affected by a
highly concentrated oligopolistic manufacturing industry and find evidence of heterogeneous
purchasing at the hospital level, consistent with a recent NAO report. I conclude that the NHS
is not exploiting its potential buyer power, leaving itself susceptible to manufacturer seller
power. I identify evidence potentially consistent with market sharing of regional and product
markets by the manufacturers.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Users 2259 not found.
Date Deposited: 12 Mar 2014 15:28
Last Modified: 12 Mar 2014 15:28


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