Validation of the Italian version of the HOOS-12 in people with total hip arthroplasty

Background The Hip disability and Osteoarthritis Outcome Score (HOOS) is a widely used patient-reported outcome measures for assessing symptoms, physical function, and health-related quality of life (QoL) in individuals with hip disorders. Although the full version has been validated across several languages, including Italian, its length may limit feasibility in time-constrained clinical settings. A 12-item short version (HOOS-12) was developed to improve feasibility while retaining core domains of pain, function, and QoL, showing good measurement properties. This study aimed to validate the Italian HOOS-12 and evaluate its measurement properties in patients with total hip arthroplasty. Methods Demographic and clinical data of adult patients with total hip arthroplasty hospitalized for acute inpatient rehabilitation were retrospectively obtained. Participants completed the full HOOS, the Harris Hip Score (HHS), and the Functional Independence Measure at both admission and discharge. HOOS-12 scores were derived from the corresponding items of the full HOOS. Structural validity was assessed using confirmatory factor analysis, and multi-group analysis was conducted to explore measurement invariance for cross-cultural validity. Construct validity and responsiveness were evaluated through a-priori hypothesis testing based on correlation analyses and effect sizes. Internal consistency was assessed using Cronbach’s alpha. Floor and ceiling effects were also examined. All analyses were conducted in accordance with COSMIN guidelines. Results Confirmatory factor analysis supported the three-factor structure (pain, function, and QoL) of the HOOS-12. Total and subscale scores generally showed strong correlations with the full HOOS and the HHS scores, confirming 77% of a-priori hypotheses. Responsiveness was supported by large effect sizes and moderate-to-strong correlations between change scores of the HOOS-12 and those of the comparator instruments. Changes in total HOOS-12 also discriminate between improved and not-improved patients based on changes in HHS. Internal consistency was generally good across domains. A ceiling effect was observed only in the pain domain at discharge. Conclusions The Italian version of the HOOS-12 demonstrated good structural validity, construct validity, internal consistency, and responsiveness in patients undergoing acute rehabilitation after total hip arthroplasty. Its brevity and adequate measurement performance support its use in clinical practice and research within Italian-speaking populations. Trial registration Not applicable.