Are the Harris Hip Score and the Hip Outcome Score valid patient-reported outcome measures for femoroacetabular impingement syndrome?

Background: The International Hip Outcome Tool (iHOT-33) is a reference instrument among the Patient-Reported Outcome Measures (PROMs) to assess people with hip disorders, including femoroacetabular impingement (FAI) syndrome. Older questionnaires such as the Harris Hip Score, or its modified version (mHHS), and the Hip Outcome Score (HOS), through the full version or its subscales (Activities of Daily Living-ADL; and Sports) are still used in the clinical setting and their construct validity is so far underexplored.

Objective: To assess the construct validity of mHHS and HOS-ADL compared with iHOT-33 by hypothesis testing in a large sample of patients with FAI syndrome.

Methods: This retrospective study was conducted with data records from patients with FAI syndrome seeking care at a private physical therapy clinic between 2013 and 2018. All participants completed the three questionnaires (mHHS, HOS-ADL, and iHOT-33) during the physical therapy initial assessment.

Results: From the 523 patients with FAI syndrome found in the clinic's database, 373 were eligible for this study. An acceptable agreement (r>0.70) was found between HOS-ADL and iHOT-33 (r = 0.77, 95%CI: 0.73, 0.81), but not between mHHS and iHOT-33 (r = 0.68, 95%CI: 0.62, 0.73). HOS-ADL score presented an acceptable agreement with iHOT-Symptoms subscale score (r = 0.78, 95%CI: 0.73, 0.81), while mHHS score did not (r = 0.68, 95%CI: 0.62, 0.73). Neither HOS-ADL or mHHS presented an acceptable agreement with iHOT-Sport, iHOT-Job, or iHOT-Social scores.

Conclusion: The HOS-ADL score, but not mHSS score, is an acceptable measure of health-related quality of life in patients with FAI syndrome.