JMIR Publications

ABSTRACT

Background:

Patient reported outcome measures (PROMs) are commonly used to report outcomes after hip and knee arthroplasty but response rates are rarely complete. Given that pre-operative health status (as measured by PROMs) is a strong predictor of outcomes (using the same measures) and that these outcomes may influence the response rate, it is possible that post-operative response rates may be influenced by pre-operative health status.

Objective:

This study aims to test the association between pre-operative PROMs and post-operative response status following hip and knee arthroplasty.

Methods:

Data from the PROMs program of a large national registry were used. Pre-operative PROMs were the Oxford Hip Score or Oxford Knee Score, EQ5D Utility Index and the EQ visual analogue scale (VAS) for overall health. Logistic regression, adjusting for age, sex, body mass index (BMI) and American Society of Anesthesiologists (ASA) Physical Status Classification System, was used to test the association between each pre-operative PROM and response status for the 6-months post-surgery survey.

Results:

Data from 9,499 and 16,539 patients undergoing elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) for osteoarthritis, respectively, were included in the analysis. Adjusting for age, sex, BMI and ASA, there was no significant difference in response status at 6 months based on the pre-operative Oxford Hip or Knee Scores (OR 1.00, 95% CI 0.99 to 1.01 for both, p = 0.70 for THA, p = 0.85 for TKA). Healthier patients (based on the EQ VAS scores) pre-operatively were more likely to respond at 6 months, but this difference was negligible (OR 1.00, 95% CI 1.00 to 1.01 for THA and TKA, p = 0.004 for THA, p < 0.001 for TKA). Pre-operative EQ Utility Index was not associated with response rate at 6 months for THA (OR 1.14, 95% CI 0.96 to 1.36, p = 0.13) or TKA patients (OR 1.05, 95% CI 0.91 to 1.22, p = 0.49).

Conclusions:

Patients who respond to PROMs surveys at 6 months post THA and TKA demonstrated similar pre-operative PROMs scores to those who did not respond. This can allay concerns that differences in pre-operative pain, function and quality of life might introduce bias when assessing surgical outcomes where there is loss to follow-up post-operatively.