The health benefits of regular activity and exercise have been clearly shown in many studies. Adults have been advised to exercise at least 30 minutes every day if possible. National and international guidelines are for 30 minutes of moderately or vigorously intense physical activity five to seven days each week. But patients with osteoarthritis (OA) have great difficulty following this guideline.
For those patients who have a total hip replacement (THR), activity after surgery remains important. Their level of independent living may depend on it. In this study, scientists at the Center for Human Movement Sciences in the Netherlands try to predict the amount of physical activity that patients engage in after a THR.
They used two well-known surveys to measure physical activity after THR. The first was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The second was the Short Questionnaire to Assess Health-Enhancing Physical Activity (SQUASH). Patients with their first (primary) THR and those who had a second (revision) THR were included. The operation was done at least one year before the study began.
The WOMAC indirectly predicts level of activity because it measures pain, stiffness, and decreased physical function. The SQUASH measures the frequency (how often), intensity (effort), and duration (time per day) of regular physical activity.
The information gathered using these two tools can be compared to the recommended national and international guideline. Patients were asked questions about leisure-time and sports activities, travel, and household activities. Information on work and school activities was also reported. Results were summarized based on two categories: patients met the guidelines or patients did not meet the guidelines.
The authors report that the WOMAC score was not a good test to use when predicting physical activity after a THR. Only 60 per cent of the adults surveyed could be classified into one of the two categories correctly. These results may be explained by the fact that physical activity may not be linked just with physical ability or limitations. It may be that social, psychologic, or environmental factors play a part in the level of physical activity after THA.
Using the WOMAC along with the SQUASH may be a better measure of activity. In this way, it is possible to identify physical limitations in function and learn something about physical activity patterns. The SQUASH only takes a few minutes to complete. The survey is self-administered, which means the patient can fill out the survey without any help. Another survey that might work equally well (if not better than the SQUASH) along with the WOMAC is the International Physical Assessment Questionnaire (IPAQ).
More research is needed to find a reliable and valid measure of physical activity after THR that’s easy to complete. The results of this study did not support the use of the WOMAC for this purpose.