There are two ways results can be measured after a total hip replacement (THR). One is by self-report. The other is performance-based. Self-report involves a survey or questionnaire filled out by the patient. Questions are asked to measure pain, stiffness, and function. Self-report tools can be filled out at home and mailed in. Or they can be completed on-line via the Internet. A clinic visit is not necessary.
Performance-based tests require the patient to actually perform tests of physical function. This may include activities such as walking (distance and speed) and sit-to-stand or balancing (skill and timed tests).
Studies show a big difference between self-reported function and performance-based tests. This study was designed to find out why this difference occurs. After completing both kinds of tests (before and after surgery), the results were compared. Once again, results were very different between the two types of tests. The main reason seemed to be pain.
Patients with hip pain were unable to sort out pain and physical function. Even when they could accomplish a task like walking, they rated their function as lower than it really was. This was true even after the pain improved. This finding suggests that even low levels of pain affect how people view their own physical function.
The authors advise using both types of testing after a THR. Using self-report and performance-based tests will provide a better view of the patient’s true abilities. Using different tests also helps assess pain, overall health, and specific activity level.