The forgotten joint score-12 is a valid and responsive outcome tool for measuring success following hip arthroscopy for femoroacetabular impingement syndrome

PurposeThe forgotten joint score-12 (FJS-12) is an outcome questionnaire designed to evaluate joint awareness. The responsiveness and validity of the English language version of the FJS-12 in patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) is not known.MethodsConsecutive patients undergoing hip arthroscopy for a diagnosis of FAI were prospectively followed up over a 1 year period. Patients completed preoperative and postoperative FJS-12, EuroQol 5 Dimension (EQ-5D-5L), and the 12-item international hip outcome tool (iHOT-12). We evaluated construct validity with Spearman correlation coefficients for the FJS-12, and responsiveness by way of effect size and ceiling effects.ResultsForty-six patients underwent hip arthroscopy, of which 42 (91%) completed post-operative PROMs at 1 year follow-up. Construct validity was strong with the iHOT-12 (r = 0.87) and also the EQ-5D-5L (r = 0.83). The median postoperative FJS score was 50.2 (IQR 64). The mean change in score for the FJS-12 was 31 points (SD 31) (p