Psychometric properties of the Italian version of the Forgotten Joint Score in patients with total hip arthroplasty

Item-reduced Forgotten Joint Score provides adequate psychometric properties in ACLR patients

Purpose

The purpose of this study was to evaluate content validity, test-retest reliability, internal consistency, construct validity, responsiveness and floor/ceiling effects of Forgotten Joint Score (FJS) for assessing functions in activities of daily living (ADL) following anterior cruciate ligament reconstruction (ACLR) and perform an item reduction of FJS.

Methods

Swedish-speaking ACLR patients in one surgical clinic were eligible. Content validity was evaluated through patient responses and patient and expert clinician relevance ratings, omitting items with low relevance. Principal component factor analysis, Cronbach's ⍺, paired t test, correlations between FJS and Knee Injury and Osteoarthritis Outcome Score (KOOS), Cohen's d effect sizes (ESs) and standardized response mean (SRM) were used to evaluate internal consistency, test-retest reliability, construct validity and responsiveness. Floor/ceiling effects were calculated. FJS was expected to reveal one dominant factor, a Cronbach's ⍺ between 0.70 and 0.95, correlations >0.50 to all KOOS subscores, highest for ADL, moderate ES and SRM, floor/ceiling effects <15%.

Results

One hundred and seventy-six participants (103 for assessing internal consistency, construct validity, responsiveness and floor/ceiling effects; 73 for assessing test-retest reliability and content validity) were included. Item reduction yielded a nine-item FJS (FJS-9). FJS-12 and FJS-9 demonstrated sufficient content validity (95% confidence interval [CI], 2.5-3.1, respectively, 2.9-3.3). FJS-9 was found unidimensional, and FJS-12 was multidimensional. Cronbach's ⍺ was 0.94 for FJS, and the intraclass correlation coefficient > 0.90. FJS showed significant correlations >0.65 to all KOOS subscales, moderate ES and SRM > 0.50. No floor/ceiling effects were found.

Conclusion

FJS-9 demonstrated adequate validity for the evaluation of joint awareness in ACLR patients and can be a valuable tool to assess ADL and joint awareness.

Level of Eidence

Level III.

Psychometric properties of the Disability of Arm Shoulder and Hand (DASH) in subjects with frozen shoulder: a reliability and validity study

BACKGROUND

Frozen Shoulder (FS) is a painful condition characterized by severe pain and progressive restriction of shoulder movement, leading to functional impairment and reduced quality of life. While different Patient Reported Outcome Measurements (PROMs) tools exist for assessing shoulder diseases, few specific PROMs are validated for FS patients.

PURPOSE

This study aims to assess the psychometric properties of the Disability of Arm, Shoulder, and Hand (DASH) questionnaire in FS patients.

METHODS

One hundred and twenty-four subjects (mean ± SD age = 55.4 ± 7.9 years; 55.6% female) diagnosed with FS were included and completed the DASH questionnaire, the Numerical Pain Rating Scale (NPRS), the Shoulder Pain and Disability Index (SPADI), and the Short-Form Health Survey 36 (SF-36). Floor or ceiling effects were investigated. Structural validity was analysed through a unidimensional Confirmatory Factor Analysis (CFA), internal consistency through Cronbach's alpha, test-retest reliability through the Intraclass Correlation coefficient (ICC), measurement error through the Standard Error of Measurement (SEM), and the Minimum Detectable Change (MDC), and construct validity through the hypothesis testing with the correlation with the other outcome measures used.

RESULTS

No floor or ceiling effects were observed. CFA confirmed a one-factor structure after addressing local item dependency (Root Mean Square Error of Approximation = 0.055; Standardized Root Mean Square Residual = 0.077; Comparative Fit Index = 0.970; Tucker-Lewis Index = 0.968). Cronbach's alpha was high (= 0.951), and test-retest reliability was excellent (ICC = 0.999; 95% CI: 0.998-1.000). SEM was equal to 0.5 points, and MDC to 1.5 points. Construct validity was considered satisfactory as 80% of the a-priori hypotheses were met.

CONCLUSION

The DASH questionnaire demonstrated good psychometric properties in FS patients, supporting its use as a valuable tool for assessing the impact of FS in clinical and research settings.

Rasch analysis of the forgotten joint score in patients with total hip arthroplasty

OBJECTIVE

To assess the internal construct validity, including local independence, unidimensionality, monotonicity, and invariance, reliability, and targeting of the Forgotten Joint Score within the Rasch Measurement Theory framework.

DESIGN

Cross-sectional study.

PATIENTS

A total of 111 patients with total hip arthroplasty at least 3 months after surgery.

METHODS

The Forgotten Joint Score was submitted to each subject during their rehabilitative treatment in an Italian centre and then to Rasch analysis.

RESULTS

The base Rasch analysis showed a satisfactory fit to the model with strict unidimensionality and no differential item functioning. However, monotonicity (11 out of 12 items showed disordered thresholds) and local independence were  violated. After rescoring 10 items and creating 5 subtests to account for local dependence, the scale satisfied all the other Rasch model requirements (i.e. invariance, local independence, monotonicity, unidimensionality, and multi-group invariance), with reliability indexes (> 0.850) for measurement at the individual level and proper targeting. A raw-score-to-measure conversion table was provided.

CONCLUSION

After structural (i.e. collapsing items categories) and non-structural (i.e. creating subtests) strategies, the Forgotten Joint Score satisfied the measurement requirements of the Rasch model, and it can be used in patients with total hip arthroplasty in clinical and research settings.