The Daily Activity Questionnaire: a novel questionnaire to assess patient activity after total hip arthroplasty.

Expensive electronic accelerometers are the only validated method to determine patient activity levels. The aim of this study was to develop a clinical questionnaire to assess patient activity. The Daily Activity Questionnaire (DAQ) was developed and evaluated using 3 groups of patients with osteoarthritis of the hip. A total of 160 patients underwent 855 days of monitoring. Practicability, reliability, and validity of the new questionnaire were assessed. The test-retest reliability of the DAQ was comparable to the electronic accelerometer StepWatch (ICC = 0.77-0.89). A significant correlation between the DAQ and the StepWatch was found (r = 0.742). The DAQ is a reliable and valid instrument to measure patient activity.