Comparison of the University of California–Los Angeles Shoulder Scale and the Simple Shoulder Test With the Shoulder Pain and Disability Index: Single-Administration Reliability and Validity

Abstract

Background and Purpose. Shoulder scales are often used to evaluate treatment efficacy, yet little is known about the psychometric properties of these scales. Only one scale has undergone psychometric scrutiny: the Shoulder Pain and Disability Index (SPADI). This study compared 2 shoulder measures—the University of California-Los Angeles (UCLA) Shoulder Scale and the Simple Shoulder Test (SST)—with the SPADI. Subjects. One hundred ninety-two patients with shoulder disorders were recruited from one physician's office to complete the self-report sections of the 3 scales. Methods. Cronbach alpha values and standard errors of measurement (SEM) were calculated for each of the multi-item subscales. Validity was examined through calculation of correlation coefficients among the 3 scales. Factor analysis was completed to assess the underlying constructs of the SPADI and the SST. Results. Cronbach alpha values ranged from .85 to .95. The SEM values for the multi-item scales ranged from 4.75 to 11.65. Evidence for validity to reflect function was indicated by the correlation between the SST and the SPADI disability subscale. The factor analysis of the SPADI revealed loading on 1 factor, whereas the SST loaded on 2 factors. Conclusion and Discussion. All scales demonstrated good internal consistency, suggesting that all items for each scale measure the same construct. However, the SEMs for all scales were high. Factor loading was inconsistent, suggesting that patients may not distinguish between pain and function.

Measuring shoulder function: A systematic review of four questionnaires

“…Most of the studies that have evaluated the dimensional structure of the SPADI have suggested that it has 2 dimensions (7,45,47,48), with a majority of disability items loading on the first factor and a majority of pain items loading on the second. Conversely, Bumin et al (14) extracted 3 domains in the Turkish version of the SPADI, whereas Roddey et al (46) extracted only one factor. This suggests that the scale may have 1-3 dimensions, depending on the groups evaluated.…”

“…Although the SST claims to measure a single construct, it has been suggested that the SST is a 2-dimensional scale (46,47). According to Roddey and colleagues, the first dimension measures what patients can do with their shoulder and the second dimension measures the patient's comfort with their shoulder at rest (46). As for the ASES, factor analysis suggests that it evaluates 2 dimensions (pain and function) (47).…”

Measures of adult shoulder function: Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH) and Its Short Version (QuickDASH), Shoulder Pain and Disability Index (SPADI), American Shoulder and Elbow Surgeons (ASES) Society Standardized Shoulder Assessment Form, Constant (Murley) Score (CS), Simple Shoulder Test (SST), Oxford Shoulder Score (OSS), Shoulder Disability Questionnaire (SDQ), and Western Ontario Shoulder Instability Index (WOSI)

“…Very low and very high function were not precisely measured (39). The 2 subscores pain and function could not be supported by factor analysis (33, 38, 42).…”

“…Relevant settings (aims and analysis [references]) for the SPADI are as follows: Shoulder pain (development of the SPADI [30]) Shoulder instruments (important comparative reviews [7, 13]) Various upper extremity diagnoses (reliability, minimal detectable difference [MDD], minimum clinically important difference [MCID] [21]) Various shoulder diagnoses (validity [32]) Adhesive capsulitis (factor analysis [33]) Adhesive capsulitis (reliability, validity, responsiveness [20, 34]) Rotator cuff (reliability, validity [35]) Rotator cuff, local infiltration (MCID [36]) After shoulder arthroplasty (validity, MDC [6, 31]) Total shoulder arthroplasty (responsiveness [19]) Various shoulder surgery (reliability, responsiveness [37]) Orthopedic practice (validity, factor, MDC, MCID [38]) Orthopedic practice (Rasch, partial credit model [39]) Primary care (validity, responsiveness [40]) Outpatient physiotherapy (validity, responsiveness [41]) Community volunteers (factor analysis [42]) …”

Matrix Metalloproteinase Levels as a Marker for Rotator Cuff Tears

“…The correlation of the severity of pain and functional impairment was rated by the UCLA Shoulder Rating Scale, 19 which has demonstrated good internal consistency when compared with the gold-standard Shoulder Pain and Disability Index. 20 A score .27 is considered excellent, and a score ,27 is fair or poor. The score is derived from the patient's self-reported level of pain, upper-extremity function, and physician assessment of ROM.…”