An analysis of choice: a case study on hip prostheses

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.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of East Anglia

Year dc:date.issued

2011

Author dc:creator

• Davies, Charlotte

Language dc:language

en