Abstract
Introduction and Aims: The aim was to study: 1) Patients’ ability to recall their pre-operative function following total hip replacement and how this recall alters with time. 2) Whether validated quality of life (QOL) assessment tools can be administered in the post-operative period to assess pre-operative function.
Method: The null hypothesis was: There is no correlation between functional scores collected pre-operatively and those collected post-operatively. Patients admitted for primary and revision hip arthroplasty between September 2002 and January 2003 were included.
Subjects completed the same questionnaire regarding pre-operative function before surgery, and then three days, six weeks and three months post-operatively. The questionnaire was a combination of the WOMAC, Oxford-12 and SF-12 questionnaires. Pearson’s correlation coefficient was used to evaluate the correlation between the pre- and post-surgery scores, and intra-class correlation coefficient (ICC) was used to assess agreement. Test-retest reliability was evaluated by Kendall’s Tau-b statistic.
Results: One hundred and four patients with a mean age of 61 years were included. There were 57 female patients and 47 males, 79 patients had primary hip replacements and 25 had revisions.
The results showed excellent correlation between pre-operative scores and those from all three postoperative time points. Pearson’s correlation coefficient for the WOMAC score was 0.75, 0.78 and 0.87 at three days, six weeks and three months respectively. The values for the Oxford-12 were 0.83, 0.78 and 0.92 at the same time points, and for the SF-12 they were 0.71, 0.63 and 0.81.
Agreement between pre- and post-operative scores was high. The ICC results for the WOMAC score at the same time points were 0.86, 0.88, and 0.93. For the Oxford-12 they were 0.91, 0.88 and 0.96 and for the SF-12 they were 0.83, 0.77 and 0.9.
Kendall’s Tau-b statistic showed high degrees of reliability for all three measures. The values for the WOMAC score at the three time points were 0.64, 0.61 and 0.72, and the results for the Oxford-12 and SF-12 scores were similarly high.
The effects on the statistics of age, sex, unilateral versus bilateral disease, and primary versus revision surgery were assessed, and no differences were found.
Conclusion: We found a high degree of correlation, agreement and test-retest reliability between QOL scores taken before hip replacement and those taken up to three months afterwards. Patients were able to recall their pre-operative functional status after surgery, and accurate pre-operative data may be collected retrospectively during the early post-operative period.
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.
