Responsiveness and clinically important differences of the Western Ontario Rotator Cuff (WORC) Index in surgical and non-surgical treatment groups with different follow-up periods: A systematic review and meta-analysis

Maryam Farzad; Hassan Jafari; Joy C MacDermid; Milad Ataeian

doi:10.1177/17585732241268631

Responsiveness and clinically important differences of the Western Ontario Rotator Cuff (WORC) Index in surgical and non-surgical treatment groups with different follow-up periods: A systematic review and meta-analysis

Shoulder Elbow. 2024 Aug 1:17585732241268631. doi: 10.1177/17585732241268631. Online ahead of print.

Authors

Maryam Farzad^{1

2}, Hassan Jafari³, Joy C MacDermid^{4

5}, Milad Ataeian⁶

Affiliations

¹ Hand and Upper Limb Center, St Joseph's Health Center, School of Physical Therapy, Department of Health and Rehabilitation Sciences, University of Western Ontario, London, Ontario, Canada.
² School of Occupational Therapy, the University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
³ Department of Biostatistics & Health Informatics, Institute of Psychiatry, Psychology& Neuroscience, King's College London, London, UK.
⁴ Physical Therapy and Surgery, Western University, London, Ontario, Canada.
⁵ Clinical Research Lab, Hand and Upper Limb Centre, St Joseph's Health Centre, London, Ontario, Canada.
⁶ School of Physical Therapy, Department of Health and Rehabilitation Sciences, University of Western Ontario, London, Ontario, Canada.

Abstract

Background: This study reviews and meta-analyzes the responsiveness and minimal clinically important difference (MCID) of the Western Ontario Rotator Cuff (WORC) Index for various patient populations and treatment durations.

Methods: A comprehensive search in PubMed, Embase, Web of Science, and CINAHL identified studies on the responsiveness or MCID of the WORC in shoulder conditions. Two authors independently screened articles. Study quality was appraised using COSMIN and GRADE guidelines. Responsiveness was evaluated using anchor-based MCID and distribution-based standardized mean differences (SMDs) computed with Hedges' g. A random-effect model addressed study variability, and heterogeneity was assessed with the chi-squared test and I² statistic.

Results: The 12 studies yielded high-quality evidence supporting the WORC's responsiveness. A meta-analysis of 1326 observations revealed a significant overall effect size (SMD) of 0.91 (95% CI: 0.56 to 1.26; p < 0.0001), with high heterogeneity (I² = 91.2%). Subgroup analyses showed larger effect sizes for long-term follow-ups (SMD = 1.28) and surgical treatments (SMD = 1.14). The average MCID was 17 for conservative treatments within six months, 26 for surgical procedures, and 29 for follow-ups over six months.

Conclusion: The WORC measures improvements in rotator cuff conditions, with varying MCID values for different treatments and durations.

Keywords: Western Ontario Rotator Cuff Index; meta-analysis; minimum clinically important difference; orthopedic research; patient-reported outcome measures; systematic review.

Publication types

Review