Comparing the Responsiveness of the Global Rating Scale With Legacy Knee Outcome Scores: A Delaware-Oslo Cohort Study

Jessica L. Johnson, James J. Irrgang, May Arna Risberg, Lynn Snyder-Mackler

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Background: The selection of patient-reported outcome measures (PROMs) is essential for obtaining meaningful information to treat a patient, determine a plan of care, and make clinical decisions; however, the process of selecting PROMs for clinical care is difficult, with the need to balance these multiple factors. Variation makes it difficult to compare data across providers and studies. Hypothesis/Purpose: The purpose was to determine the responsiveness of 4 PROMs via effect size and the presence of a ceiling effect in the 5 years after anterior cruciate ligament reconstruction (ACLR). We hypothesized that the single-item Global Rating Scale (GRS) would have an effect size and ceiling effect similar to the commonly used legacy PROMs. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Of the 300 participants, 218 had ACLR, completed postoperative progressive criterion-based rehabilitation early after surgery, and were followed for 5 years. We collected data based on the GRS, the Knee Outcome Survey–Activities of Daily Living Scale (KOS-ADLS), the International Knee Documentation Committee–Subjective Knee Form (IKDC-SKF), and the KOOS (Knee injury and Osteoarthritis Outcome Score) before and after training and at 6, 12, 24, and 60 months after ACLR. Results: The IKDC-SKF had the largest effect sizes and lowest ceiling effects. The GRS had a similar size and change in both effect size and ceiling effect when compared with the longer PROMs. The GRS and IKDC-SKF had a correlation of 0.72, and the GRS had a minimal detectable change of 2.9 or 4.8, depending on methodology. Conclusion: The GRS responded similarly to the IKDC-SKF, KOS-ADLS, and KOOS and was responsive to patient change. The ease of use and patient-specific nature of the question means that it may be appropriate to use the GRS in clinical care as a consistent measure throughout the course of rehabilitation.

Original languageEnglish (US)
Pages (from-to)1953-1960
Number of pages8
JournalAmerican Journal of Sports Medicine
Issue number8
StatePublished - Jul 1 2020

Bibliographical note

Funding Information:
The authors thank Aaron Boulton for biostatistics consultation. The authors thank all of the laboratory assistants and graduate students who have been a part of this longitudinal study, including David Logerstedt, Andrew Lynch, Mathew Failla, Ryan Zarzycki, Hege Grindem, H?vard Moksnes, Ingrid Eitzen, Karin Rydevik, and Marte Lund. The authors thank the University of Delaware Physical Therapy Clinic. The authors thank the Delaware Research Institute and Martha Callahan for assistance in participant recruitment, scheduling, and data management. The authors thank the Norwegian Sports Medicine Clinic (Nimi) for supporting the Norwegian Research Center for Active Rehabilitation with rehabilitation facilities and research staff, in particular research coordinator Kristin Bolstad.

Funding Information:
One or more of the authors has declared the following potential conflict of interest or source of funding: The Delaware-Oslo ACL Cohort Study is supported by grant R37 HD037985 from the National Institutes of Health. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Publisher Copyright:
© 2020 The Author(s).


  • ACL
  • knee
  • patient-reported outcome measures
  • rehabilitation


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