Total Hip Arthroplasty: Psychometric Validation of the Italian Version of Forgotten Joint Score (FJS-12)

Background: Patient’s satisfaction after surgery was traditionally assessed by pre, and post-surgical scores and Patient-Reported Outcome Measures (PROMs) scales. Patients treated by Total hip arthroplasty (THA) usually perform well; therefore, it is useful to have a PROMs’ scale with a low ceiling effect as the Forgotten Joint Score-12 (FJS-12). PROMs have to be validated in the local language to be used. This study aims to perform a psychometric validation of the Italian version of FJS-12 in a group of consecutive patients treated by THA.Methods: Each patient completed both the Italian version of FJS-12 and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) in preoperative evaluation, after two weeks and 1 month, 3 months and 6 months postoperative follow-up. The reliability, internal consistency, test-retest reliability, and measurement error were evaluated.Results: 53 patients were included. Cronbach’s α between 0.6 and 0.9 indicated good internal consistency for the FJS-12. The test-retest reliability was acceptable. The Pearson correlation coefficient between the FJS-12 and WOMAC was 0.238 (P=0.087) at baseline, r = 0.637 (P < 0.001) at 1 month, r = 0.490 (P < 0.001) at 3 months and r = 0.572 (P < 0.001) at 6 months. The ceiling effect was above the acceptable range (15%) for FJS-12 in 1 month (26.4%) and WOMAC in 6 months follow-up (24.5%).Conclusions: An excellent test-retest reliability, a good internal consistency, and a good validity by medium-high correlation with the WOMAC were assessed for FJS-12. However, the responsiveness for the FJS-12 score was not assessed.