Abstract
Introduction and Aims: Austin Moore and Thompson hemiarthroplasties are commonly used for the management of subcapital neck of femur fractures, particularly in the frail elderly. There are no published studies that directly compare the results of these two procedures. The Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR) has reviewed outcomes for these prostheses.
Method: Data from the AOA NJRR collected from participating hospitals between September 1999 and December 2002 were used to test for differences in revision rates between these two prostheses. Mortality data from the National Death Index were used to censor the time of follow-up and to compare mortality rates following surgery. Further analyses were undertaken to examine the effects of age, gender, diagnosis and regional variation.
Results: The Registry recorded 4080 Austin Moore and 1111 Thompson hemiarthroplasties. Of these, 4023 (98.6%) Austin Moore prostheses were cementless and 1010 (90.9%) Thompsons were cemented. The distributions of age and gender were similar for the two prostheses. There were regional differences in the use of monoblock prostheses during the data collection period. In Victoria, all partial monoblock prostheses used were Austin Moore (N=1560). This contrasts to Queensland and Western Australia where 62.8% and 75.8% respectively of all partial monoblock hip replacements were Thompsons. The cementless Austin Moore prosthesis had a significantly higher rate of revision (122/4023, 3%) than the cemented Thompson prosthesis (9/1010, 0.9%). A Cox model yielded a hazard ratio, adjusted for age and gender, of 3.94 (95% CI: 2.00, 7.76; p < 0.001). None of the 57 cemented Austin Moore and four of the 101 (4%) cementless Thompsons required revision. The cumulative mortality rates for the period to 2001 were similar for the two prostheses (Austin Moore 23.3% and Thompson 24.0%). In the states where sufficient numbers of both types of prostheses were used the difference in outcomes were consistent with the overall results.
Conclusion: The use of the cementless Austin Moore prostheses is associated with an almost four-fold increase in the rate of revision when compared to the cemented Thompson prosthesis.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
