The Patient Acceptable Symptomatic State for Commonly Used Patient-Reported Outcomes After Nonoperative Management of Hip Femoroacetabular Impingement

Patient Acceptable Symptomatic State (PASS) values for commonly used patient-reported outcome measures (PROMs) are known for operatively treated patients with femoroacetabular impingement syndrome (FAIS) but have not been established for conservative treatment. The objective of this study was to determine the PASS in the population with FAIS managed non-operatively for International Hip Outcome Tool -33 (iHOT-33), Hip Outcome Score - Activities of Daily Living (HOS-ADL), Pain Visual Analog Scale (VAS). Over fifteen months, patients who were treated non-operatively with an expert-validated physiotherapy protocol (HipFit10) for a period of 3-months at two sites (Women's College Hospital and St-Michael's Hospital) were prospectively enrolled. Patients completed the iHOT-33, HOS-ADL, and Pain-VAS at baseline and 6 months after beginning treatment. Receiver operating characteristic curve analyses were conducted to determine PASS cutoff point. Multivariable regression analyses were performed to determine the effect of patient factors (age, sex, body mass index), radiographic markers (Tönnis classification grade, alpha-angle, center-edge, angle), and disease severity (symptom duration and baseline activity score) on the likelihood of achieving PASS. Of the 214 patients enrolled, 121 (57%) were female, and the mean age was 34 years. The median symptom duration was 24 months. The mean iHOT-33 score was 42.9 (SD16.7) at baseline and 54.2 (SD 22.0) at 6 months. The iHOT-33 score for PASS is 50 (Specificity 91%, Sensitivity 82%, AUC 0.95). The mean HOS-ADL was 72.9 (SD16.0) at baseline and 77.1 (SD17.1) at 6 months. The HOS-ADL score for PASS is 65.7 (Specificity 81%, Sensitivity 86%, AUC 0.90). The mean Pain-VAS score was 53.7 (23.1) at baseline and 41.9 (SD25.4) at 6 months. The Pain-VAS score for PASS is 36 (Specificity 67%, Sensitivity 85%, AUC 0.87). Baseline activity scores were significantly predictive of achieving PASS for iHOT-33 and Pain-VAS. Patients with highest tertile baseline iHOT-33 scores were more likely to achieve PASS for all PROs (P < 0 .005). Patient factors, radiographic markers, and symptom duration did not have an effect on the likelihood of achieving PASS. This study determined the PASS value for iHOT-33 to be 50, HOS-ADL 65.7, and Pain VAS 36 among FAIS patients treated non-operatively. iHOT-33 PASS is more sensitive and specific. Baseline activity score was a positive prognostic variable to achieve PASS for iHOT-33 and Pain-VAS but not HOS-ADL. Higher baseline iHOT-33 score is predictive for achieving PASS for all scores. Symptom duration, patient characteristics, and radiographic markers are not prognostic. The information in this study can be used in counseling individual patients as to anticipated outcomes and in study design.