Percentage of patients 18 years of age and older who completed a baseline and, within the CY(calendar year) reporting period of Jan. 1, 20xx - Dec.31, 20xx, a follow-up quality of life (QoL) patient-reported outcomes assessment (VR-12, SF-12, SF-36, PROMIS Global 10 or equivalent Computer Adaptive Test (CAT) assessment if available) which yielded a physical component score that showed a statistically significant improvement in comparison to initial assessment or who had already reported a score in which there is no room for statistical improvement. The use of Patient Reported Outcomes (PROs) in clinical research is well documented. In addition, the AAOS Quality Outcomes Work Group recommends that QoL PROs in the clinical setting can lead to improved care.