PROMIS is an efficient metric to assess outcomes in patients with patellofemoral malalignment with several advantages over conventional scores.
The purpose of this study was to investigate the PROMIS PF CAT instrument in a population of patients scheduled to undergo surgical correction of patellofemoral malalignment and chondral disease.
Eligible patients were prospectively enrolled at the time of indication for surgery. Enrolled patients completed a total of six preoperative PRO instruments: SF-36 (including PF), WOMAC, MARS, AKPS, EQ-5D-5L, and PROMIS PF CAT (v1.2 or v2.0). Convergent and discriminant validity was assessed by measuring correlation between PROMIS PF CAT and other PRO instruments. Strength of correlation was measured using Spearman correlation coefficients.
In total, 45 patients (48 knees) were enrolled in the study. Fulkerson osteotomy was performed in 44 knees, and 31 knees underwent concomitant cartilage procedure (26 resurfacing, 5 microfracture). Correlations (r) between PROMIS PF CAT and knee PRO instruments are as follows: SF36-PF (r=0.73, p<0.01); KOOS pain (r=0.74, p<0.01); KOOS symptoms (r=0.45, p<0.01); KOOS QOL(r=0.66, p<0.01); KOOS sports (r=0.71, p<0.01); KOOS ADL(r=0.75, p<0.01); WOMAC function (r=0.75, p<0.01); WOMAC pain (r=0.71, p<0.01); WOMAC stiffness (r=0.35, p=0.02); Marx Activity (r=0.15, p=0.31); AKPS (Kujala) (r=0.63, p<0.01); EQ-5D-5L, (r=0.67, p<0.01). Neither floor nor ceiling effects were observed in PROMIS PF CAT or KOOS ADL. One instance (2.2%) of floor effect was observed in the SF-36 PF instrument, while 7 instances of floor effect (15.6%) were observed in the KOOS Sports instrument. Mean question burden with PROMIS PF CAT was 4.0 questions ± 0.2 questions.
PROMIS PF CAT correlated well (high or high-moderate) with all other PRO instruments except for KOOS Symptoms, WOMAC Stiffness, and Marx Activity. In patients with patellofemoral malalignment and chondral disease, PROMIS PF CAT is an efficient and reliable PRO instrument to assess patients across a wide range of knee function. PROMIS PF CAT demonstrated no floor or ceiling effect in the selected patient population.