There is increased utilization of the Patient-Reported Outcomes Measurement Information System (PROMIS) in orthopedic surgery. The current study aimed to test the reliability, construct validity and responsiveness to change of the lower extremity-specific Mobility bank of the PROMIS in patients who underwent hip arthroscopic surgery.
Patients at a large academic musculoskeletal specialty center who underwent primary hip arthroscopic surgery between November 2019 and November 2020 completed the following outcomes hip-specific and general health-related quality of life (HRQoL) measures at baseline and at 6-month follow-up: PROMIS Mobility CAT (PROMIS MO), PROMIS Pain Interference CAT (PROMIS PI), PROMIS Physical Function (PROMIS PF), modified Harris Hip Score (mHHS), iHOT-33, VAS pain, and Single Assessment Numeric Evaluation (SANE). Construct validity was evaluated using Spearman correlation coefficients. Correlation was defined as high (=0.7), high-moderate (0.61-0.69), moderate (0.4-0.6), moderate-weak (0.31-0.39) and weak (=0.3). Number of questions to completion were recorded as a marker of test burden. The percentage of patients scoring at the extreme high (ceiling) or low (floor) of each measure was recorded to measure inclusivity. Responsiveness was tested by comparing differences between baseline and 6 months, controlling for age and sex, using generalized estimating equations. Magnitudes of the responsiveness were assessed through Cohen’s d effect size.
A total of 768 patients were evaluated (54% female) age 32 ± 14 years. PROMIS MO demonstrated a strong correlation with PROMIS PF, (r = 0.78, p < 0.001), iHOT-33 (r=0.74, p<0.001), and mHHS (r=0.72, p<0.001), and a moderate correlation with PROMIS PI (r=0.68, p<0.0010. Neither PROMIS Mobility, PROMIS PI or PROMIS PF met conventional criteria for floor or ceiling effects (>15%). The mean number of questions answered (± SD) were 4.7 ± 2.1 for PROMIS MO, 4.1 ± 0.6 for PROMIS PI, and 4.1 ± 0.6 for PROMIS PF. Examination of the difference from baseline to 6 months revealed that the PROMIS and legacy measures exhibited significant responsiveness (p<0.05), with similar effect sizes between the PROMs.
This longitudinal study reveals in patients undergoing hip arthroscopy, PROMIS Mobility CAT maintains high correlation with other legacy hip-specific instruments as well as HRQoL measures, significant responsiveness to change, with low test burden compared to legacy measures. There were no ceiling or floor effects for PROMIS MO, PROMIS PF and PROMIS PI.
Level of Evidence: Level IV, retrospective case series