Factor Analysis of the KOOS Does Not Indicate the Existence of 5 Unique Subscales

• Published in: Journal of athletic training Vol. 52; no. 6; p. S286
• Main Authors: Howard, J S, Conley, C E Whale, Jacobs, C A, Lattermann, C
• Format: Journal Article
• Language: English
• Published: Dallas National Athletic Trainers Association 01-06-2017
• Subjects: Activities of daily living; Factor Analysis; Joint surgery; Maximum Likelihood Statistics; Outcome Measures; Outcomes of Treatment; Pain; Patients; Questionnaires
• ISSN: 1062-6050; 1938-162X

An abstract of a study by Howard et al determining the number of latent factors evaluated by the Knee Injury and Osteoarthritis Outcome Score (KOOS) is presented. Despite being reported as 5 separate subscale scores, the KOOS appears to evaluate two main factors "Pain and Function during ADLs" and "Function during Sports and Recreation." These results, documented among knee surgical patients, are in line with other recent adaptations of the KOOS (KOOS-JR and KOOS-PS) which were developed via item reduction of some, but not all subscales, and have been proposed for use in osteoarthritic and total knee arthroplasty patients. The results of this investigation indicate that item reduction of the full KOOS and the collapsing of subscales into no more than two domains may be warranted. Such a reduction has the potential to reduce both patient and clinician burden, while simplifying KOOS interpretation by eliminating redundant or non-discriminant questions.