Reproducibility: Reliability and agreement of short version of Western Ontario Rotator Cuff Index (Short-WORC) in patients with rotator cuff disorders

Neha Dewan; Joy C MacDermid; Norma MacIntyre; Ruby Grewal

doi:10.1016/j.jht.2015.11.007

Reproducibility: Reliability and agreement of short version of Western Ontario Rotator Cuff Index (Short-WORC) in patients with rotator cuff disorders

J Hand Ther. 2016 Jul-Sep;29(3):281-91. doi: 10.1016/j.jht.2015.11.007. Epub 2015 Dec 21.

Authors

Neha Dewan¹, Joy C MacDermid², Norma MacIntyre³, Ruby Grewal⁴

Affiliations

¹ School of Rehabilitation Sciences, McMaster University, Canada. Electronic address: dewann@mcmaster.ca.
² School of Rehabilitation Sciences, McMaster University, Canada; Hand and Upper Limb Center, St. Joseph's Hospital, London, ON, Canada; Department of Physical Therapy, University of Western Ontario, Canada; Department of Surgery, University of Western Ontario, Canada.
³ School of Rehabilitation Sciences, McMaster University, Canada; Queen's University, Kingston, ON, Canada.
⁴ Hand and Upper Limb Center, St. Joseph's Hospital, London, ON, Canada; Department of Surgery, University of Western Ontario, Canada.

PMID: 27496983
DOI: 10.1016/j.jht.2015.11.007

Abstract

Introduction: Recently, a shorter version of Western Ontario Rotator Cuff Index (Short-WORC) was proposed as a subset of 7 items from the original 21-item WORC. However, the reproducibility of the Short-WORC has not been established.

Purpose of the study: To determine reproducibility (reliability and agreement) of the Short-WORC among patients with rotator cuff disorders (RCDs).

Methods: Patients (n = 153) diagnosed with RCD completed the WORC at baseline and at 3 months post-operatively (n = 146). The Short-WORC was extracted from the full version of WORC. From this retrospective cohort, 43 patients were retested within 5 weeks, if they remained stable. Cronbach's alpha (α) and intra class correlation coefficients (ICC2,1) were used to assess internal consistency and test-retest reliability respectively. Standard error measurement (SEM), minimal detectable change (MDC90) and Bland Altman (BA) plots were used to assess agreement.

Results: No floor and ceiling effects were reported for either the Short-WORC or WORC. Cronbach's α were 0.84 and 0.90 at baseline and 0.89 and 0.95 at 3 month of follow up for Short-WORC and WORC respectively. The ICC2,1 were 0.89 and 0.91 for the Short-WORC and WORC respectively. The agreement parameters for the Short-WORC were: SEMagreement = 8.8, MDC90individual = 20.3, MDC90group = 5.1. We found substantial agreement between the two versions of WORC on BA plots with minimal (mean difference (d) <1) systematic differences between them. The limits of agreement (LOA) between two versions of WORC were similar across sessions and fell within range of -11.7 to 13.2 points at test and -14.7 to 14.7 points at retest.

Conclusion: Short-WORC and WORC demonstrates strong reproducibility and can be used for group and individual comparison of health-related quality of life (HRQoL) among patients with RCD. Wider LOA may be expected when using the Short-WORC for individual patient assessment. Reproducibility data is essential, but should be supplemented by validation of actual Short-WORC with samples representing the spectrum of RCD.

Level of evidence: N/A.

Keywords: Minimal detectable change; Quality of life; Reliability; Rotator cuff tear; Shoulder pain; Western Ontario Rotator Cuff Index.

MeSH terms

Adult
Aged
Databases, Factual
Disability Evaluation*
Female
Follow-Up Studies
Humans
Male
Middle Aged
Ontario
Orthopedic Procedures / methods
Pain Measurement
Quality of Life*
Range of Motion, Articular / physiology*
Reproducibility of Results
Retrospective Studies
Risk Assessment
Rotator Cuff / physiopathology
Rotator Cuff / surgery
Severity of Illness Index
Shoulder Impingement Syndrome / diagnosis*
Shoulder Impingement Syndrome / surgery
Shoulder Pain / diagnosis*
Shoulder Pain / surgery
Treatment Outcome