PROMIS: a valid and efficient outcomes instrument for patients with ACL tears

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.

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.

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).

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.