Preoperative Performance of PROMIS in Patients With Patellofemoral Malalignment and Chondral Disease

BACKGROUND: Use of the Patient-Reported Outcomes Measurement Information System (PROMIS) instrument has not yet been validated in patients undergoing operative treatment for patellofemoral malalignment and chondral disease. PURPOSE: To evaluate the PROMIS Physical Function Computer Adaptive Testing (PF CAT) instrument in a population of patients with patellofemoral malalignment and chondral disease relative to established patient-reported outcome (PRO) instruments. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Eligible patients were prospectively enrolled at the time of indication for surgery and completed 5 PRO instruments preoperatively: 36-Item Short Form Health Survey (SF-36); Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC); Marx activity rating scale (Marx); EuroQol 5-dimension, 5-level instrument (EQ-5D-5L); and PROMIS PF CAT. Convergent and discriminant validity was assessed by measuring correlations between PROMIS PF CAT and other PRO instruments, including the Knee injury and Osteoarthritis Outcome Score (KOOS). Strength of correlation was measured by use of Spearman correlation coefficients. RESULTS: In total, 37 patients (40 knees) were enrolled in the study. All knees underwent Fulkerson osteotomy and concomitant cartilage procedure (29 chondroplasty, 6 allograft, 5 microfracture). Mean patient age was 33.4 years, and 73% of knees were in female patients. Correlations (r) between PROMIS PF CAT and knee PRO instruments were as follows: SF-36 PF (r = 0.80; P < .01); KOOS Pain (r = 0.74; P < .01); KOOS Symptoms (r = 0.47; P < .01); KOOS Quality of Life (r = 0.68; P < .01); KOOS Sports and Recreation (r = 0.72; P < .01); KOOS Activities of Daily Living (ADL) (r = 0.80; P < .01); WOMAC Function (r = 0.80; P < .01); WOMAC Pain (r = 0.72; P < .01); WOMAC Stiffness (r = 0.38; P = .02); Marx (r = 0.22; P = .31); and EQ-5D-5L (r = 0.72; P < .01). Neither floor nor ceiling effects were observed in PROMIS PF CAT or KOOS ADL. Mean (±SD) question burden with PROMIS PF CAT was 5.6 ± 0.6 questions. CONCLUSION: In patients with patellofemoral malalignment and chondral disease, PROMIS PF CAT is an efficient and reliable PRO instrument to preoperatively assess patients across a spectrum of knee function without floor or ceiling effects.