Work, Osteoarthritis, and Joint Replacement Questionnaire

Abstract

The Work, Osteoarthritis and joint-Replacement Questionnaire (WORQ) is a specialized Patient Reported Outcome Measure (PROM) designed to quantify the functional limitations experienced by patients with knee conditions, specifically Osteoarthritis (OA) or post-joint replacement surgery, when performing work-related activities. It requires the patient to report on their perceived level of difficulty concerning 13 activities that place a load on the knee, assessed over the preceding week.

The raw scores are transformed using a standardized formula to yield a total score ranging from 0 to 100. A score of 0 indicates the maximum level of difficulty experienced or the inability to perform the activity (‘erg veel moeite/ kan ik niet’), while a score of 100 signifies no difficulty whatsoever (‘geen enkele moeite’). The WORQ is a critical tool for clinicians and researchers monitoring rehabilitation progress and assessing fitness for return-to-work following lower extremity interventions.

Keywords

Work, Osteoarthritis, Knee, Joint Replacement, Functional Assessment, PROM, Lower Extremity, Disability, Rehabilitation

Authors

Dutch version: Kuijer PPFM (2016)

Purpose

The primary purpose of the WORQ is to provide a reliable and sensitive measure of the self-reported functional capacity of individuals suffering from knee disorders, particularly those related to the demands of daily work and physical activity. It focuses specifically on activities that challenge the stability and movement of the knee joint, which are often prerequisites for occupational engagement.

By quantifying the difficulty associated with 13 specific knee-loading tasks, the WORQ helps healthcare providers identify precise areas of functional deficit. This information is crucial for tailoring rehabilitation programs, evaluating the effectiveness of surgical or conservative treatments for Osteoarthritis, and making informed decisions regarding vocational rehabilitation and return-to-work timelines.

Construct

The WORQ measures the psychological construct of Perceived Functional Difficulty in Knee-Loading Activities. This construct is rooted in the patient’s subjective experience of limitations related to the lower extremity, specifically within the context of activities that mimic or relate to occupational demands. It aligns with the World Health Organization’s International Classification of Functioning, Disability and Health (ICF) model, focusing on the domain of Activities and Participation.

The scale operationalizes this construct by asking patients to rate the degree of effort or difficulty encountered during defined physical tasks over a recent period. The resulting score is an objective reflection of the subjective burden imposed by the knee condition on the patient’s ability to perform general tasks, mobility, and movement, particularly relevant to the musculoskeletal system.

Validity

While specific detailed validation studies must be consulted for definitive data, scales like the WORQ typically undergo rigorous validation processes. Content validity is ensured by the careful selection of 13 items that are representative of common knee-loading activities required in various work and daily life settings.

Construct validity is generally established by demonstrating moderate to strong correlations with existing, validated measures of knee function and disability, such as the Knee injury and Osteoarthritis Outcome Score (KOOS) or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Furthermore, the ability of the WORQ to successfully discriminate between patient groups (e.g., pre-operative vs. post-operative patients, or symptomatic vs. asymptomatic individuals) provides evidence of its known-groups validity.

Reliability

The reliability of the WORQ, critical for its use as a monitoring tool, is assessed via standard psychometric properties. High internal consistency, often measured by Cronbach’s alpha, is expected, demonstrating that the 13 items measure a common underlying construct.

Test-retest reliability is typically evaluated over a short, stable period to ensure that scores remain consistent when no actual change in the patient’s condition has occurred. High intra-class correlation coefficients (ICC) are characteristic of a reliable measure, confirming that the WORQ provides stable and reproducible results over time when administered to patients with chronic conditions like Osteoarthritis.

Factor Analysis

Initial factor analysis often seeks to determine the dimensional structure of the WORQ. Given its focus on a singular anatomical region (the knee) and a singular domain (functional difficulty), the scale is often found to be largely unidimensional. However, depending on the specific sample studied, factor analysis might reveal sub-factors differentiating between high-demand activities (e.g., kneeling, climbing) and low-demand activities (e.g., walking short distances).

Confirmatory Factor Analysis (CFA) is generally employed to confirm the structure identified during exploratory analysis, ensuring that the 13 items load appropriately onto the intended factor(s), thereby supporting the scoring methodology which aggregates items into a single, comprehensive difficulty score.

Instrument

Test Type: Patient Reported Outcome Measure (PROM)

Format: Self-administered Questionnaire (Vragenlijst)

Language Available: Dutch (Nederlandse versie)

Population Group: Clinical and General Population

Age Group: Adult (Volwassenen)

Population Details: Individuals suffering from disorders of the musculoskeletal system, specifically bone, joint, and cartilage disorders (Bot-, gewrichts-, kraakbeenaandoeningen), affecting the lower extremity, including those undergoing or having undergone joint replacement surgery.

Test Methodology: Patients score their perceived difficulty on 13 specific knee-loading activities experienced over the past week. A formula is used to normalize the total raw score to a range of 0 to 100.

Keywords

Function, Mobility, Activities, Lower Extremity, Knee Function, Orthopedics, Psychometric Properties, Disability, Rehabilitation Outcome

Authors

Author ORCID Identifier: N/A (Information not provided in source)

Affiliation Email addresses: N/A (Information not provided in source)

Correspondence Address: N/A (Information not provided in source)

Permissions & Fee and Test Year

The Dutch version of the WORQ was published by Kuijer PPFM in 2016. Users should consult the primary author or relevant institutional bodies for current information regarding required permissions, licensing agreements, and potential fees associated with the clinical or research application of the questionnaire.

Reference’s

The primary reference for the Dutch version of the WORQ is associated with the work of Kuijer PPFM (2016). For detailed information regarding the administration and scoring, the following documents are available:

• The explanatory form (Toelichtingsformulier) for the WORQ can be downloaded here: WORQ-form.pdf
• The measurement instrument (Meetinstrument) itself can be downloaded here: WORQ-meetinstr.pdf

Items of the Work, Osteoarthritis and joint-Replacement Questionnaire

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

The WORQ assesses 13 specific knee-loading activities. While the exact textual items are not provided in the source description, they pertain to activities related to general tasks, demands, mobility, and movement of the lower extremity, crucial for assessing work-related function in patients with knee conditions.