Purpose: The current study compares the Patient Reported Outcomes Information System Physical Function Computer Adaptive Test (PROMIS PF CAT) to traditional knee PRO instruments in a healthy population undergoing surgery for ACL injuries with the following objectives: (1) identify and determine the strength of any correlations between the scores of PROMIS PF CAT and current knee PROs or their subscales that measure physical function; (2) evaluate PROMIS PF CAT's test burden; and (3) determine if PROMIS PF CAT has any floor or ceiling effects in this population.
Methods: Patients indicated for ACL surgery completed the Short Form-36 Physical Function (SF-36 PF), Knee Injury and Osteoarthritis Outcome Score (KOOS), Marx Knee Activity Rating Scale (Marx), the EuroQol 5-dimensions Questionnaire (EQ-5D), and PROMIS PF CAT. Correlations between PROs were defined as follows: High (≥ 0.7); high-moderate (0.61-0.69); moderate (0.4-0.6); moderate-weak (0.31-0.39); and weak (≤ 0.3). Floor or ceiling effects were considered significant if 15% or more patients reported the lowest or highest possible total score, respectively.
Results: 100 patients participated with a mean age of 26 years (range 11-57). The PROMIS PF CAT demonstrated high correlations with SF-36 PF (r = 0.82, p < 0.01), EQ-5D (r = - 0.70, p < 0.01) KOOS ADL (r = 0.74, p < 0.01), and KOOS Sport (r = 0.70, p < 0.01). There were no ceiling or floor effects for PROMIS PF CAT (0%). The mean number of items completed for the PROMIS PF CAT was 4.2 (median 4; range 4-11).
Conclusions: The PROMIS PF CAT shows a high correlation with commonly employed PROs that also measure physical function with low test burden and without ceiling effects in this relatively young and healthy population.
Keywords: ACL outcomes; Computer adaptive testing; PROMIS; Patient-reported outcomes.