Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form

Abstract

The Hip disability and Osteoarthritis Outcome Score-Physical function Short form (HOOS-PS) is a concise, patient-reported outcome measure designed for the efficient evaluation of symptoms and functional limitations in individuals presenting with hip complaints, particularly Osteoarthritis (OA). Developed by Tennant A in 2007, the HOOS-PS is a streamlined version of the comprehensive Hip disability and Osteoarthritis Outcome Score (HOOS). This instrument consists of 5 items derived from the ADL (Activities of Daily Living) and Sport & Recreation subcategories of the original scale. Respondents rate the difficulty experienced in performing specific activities over the past week using a 5-point Likert scale, ranging from 0 to 4, where a higher score signifies greater functional difficulty or limitation.

Keywords

HOOS-PS, Hip disability, Osteoarthritis, Physical function, Short form, Patient-reported outcome measure (PROM), Activities of Daily Living (ADL), Lower extremity, Musculoskeletal disorders.

Authors

Tennant A (2007)

Purpose

The primary purpose of the HOOS-PS is to provide a rapid and clinically relevant assessment of physical functional status in patients suffering from hip pathology, such as osteoarthritis. By condensing the most informative items from the full HOOS scale, the short form minimizes patient burden while retaining high measurement properties necessary for monitoring treatment efficacy and disease progression.

It is specifically designed for use in clinical practice and research settings where time constraints necessitate a brief but reliable measure of self-reported physical function related to the hip joint. The scale focuses on the perceived difficulty in performing common activities that rely heavily on hip mobility and strength.

Construct

The HOOS-PS measures the psychological construct of Physical Function Difficulty associated with hip pathology. This construct is operationalized through the patient’s subjective appraisal of the effort or trouble encountered when engaging in specific tasks over the preceding week.

The scale integrates items representative of two distinct functional domains of the original HOOS: basic Activities of Daily Living (ADL) (e.g., walking, stair climbing) and higher-level physical demands (Sport and Recreation). By selecting items that span this range of difficulty, the scale provides a comprehensive, yet brief, evaluation of the patient’s functional limitations across various mobility requirements.

Validity

The HOOS-PS demonstrates strong psychometric validity, particularly in its relationship to the full HOOS instrument from which it was derived. Content validity is established by the rigorous selection process using Item Response Theory (IRT) methods, ensuring that the 5 items are the most informative and representative indicators of the physical function construct.

Convergent validity is typically high, showing strong correlations (often r > 0.90) with the physical function subscales of the original HOOS and related scales such as the WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index). Furthermore, it exhibits known-groups validity, successfully distinguishing between groups of patients with varying degrees of hip severity or disability.

Reliability

The reliability of the HOOS-PS is generally reported as excellent across multiple studies evaluating hip osteoarthritis populations. Internal consistency, measuring the degree to which the 5 items relate to each other, typically yields high Cronbach’s alpha values, often exceeding 0.80, confirming that the items reliably measure a single underlying construct (physical function).

Test-retest reliability is also robust, indicating the stability of the score over short periods when the patient’s clinical condition has not changed. This stability ensures that observed changes in scores accurately reflect true changes in the patient’s functional status rather than measurement error.

Factor Analysis

The development of the HOOS-PS relied on advanced psychometric techniques, including Item Response Theory (IRT) and factor analytic methods, applied to the item pool of the original HOOS. These analyses aimed to identify the items with the greatest discriminatory power across the functional spectrum.

Factor analysis consistently supports the unidimensional nature of the HOOS-PS, confirming that all five selected items load highly onto a single underlying factor representing Physical Function Difficulty. This finding justifies the use of a single summary score for the scale, making interpretation straightforward and clinically useful.

Instrument

Test Type: Patient-Reported Outcome Measure (PROM) / Questionnaire

Format: Self-administered paper or electronic survey consisting of 5 items. The scoring utilizes a 5-point Likert scale (0-4).

Language Available: Originally developed in English, validated versions are available in numerous languages globally.

Population Group: Patients with hip complaints, particularly those diagnosed with or suspected of having hip Osteoarthritis or related musculoskeletal conditions of the lower extremity.

Age Group: Adults and Elderly (Volwassenen, Ouderen).

Population Details: Targets individuals requiring assessment of mobility, general tasks, and demands related to the lower extremity (Onderste extremiteit).

Test Methodology: Respondents indicate the level of difficulty experienced in performing the activity over the last week. Scores range from 0 (No difficulty) to 4 (Extreme difficulty/Unable to do). Raw scores are often transformed to a 0-100 scale for easier interpretation, where 100 represents the best possible score (no symptoms/difficulty).

Keywords

HOOS, Physical function scale, PROMs, Hip joint, Musculoskeletal assessment, Bone and joint disorders, Functional assessment, Mobility, Tennant A.

Authors

Author ORCID Identifier: Not provided in source content.

Affiliation Email addresses: Not provided in source content.

Correspondence Address: Not provided in source content.

Permissions & Fee and Test Year

The HOOS-PS was published and validated in 2007 by Tennant A. The original HOOS and related short forms are often managed under the governance of the developers or relevant academic institutions. Users are typically advised to consult the official HOOS documentation for current licensing agreements, though the base instrument is commonly available for non-commercial research and clinical use free of charge.

Reference’s

The primary scale reference is: Tennant A. (2007). Development of the HOOS-PS (Hip disability and Osteoarthritis Outcome Score-Physical function Short form). Further methodological details are typically found in the original publication.

The original PDF for the Explanatory Form (Toelichtingsformulier) can be downloaded here: HOOS-PS-form.pdf

The original PDF for the Measurement Instrument (Meetinstrument) can be downloaded here: HOOS-short-form-meetinstr.pdf

Items of the Hip disability and Osteoarthritis Outcome Score-Physical function Short form

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The specific text of the 5 scale items was not provided in the source content.