The Application of Computerized Adaptive Testing to the International Knee Documentation Committee Subjective Knee Evaluation Form

Abstract

Background: Patient-reported outcome measures (PROMs) are commonly used to monitor functional outcomes for clinical and research purposes; unfortunately, many PROMs include redundant, burdensome questions for patients. The use of predictive models to implement computerized adaptive testing (CAT) offer a potential solution to reduce question burden in outcomes research. Purpose: To validate the usage of an appropriate CAT system to improve the efficiency of the International Knee Documentation Committee (IKDC) Subjective Knee Form. Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: Validation was based on electronically collected patient responses from 2 separate orthopaedic sports medicine clinics. Diagnoses included, but were not limited to, meniscal lesions, ligamentous injuries, and chondral defects. The CAT system was previously developed through analysis of an electronic knee PROM database that did not contain any of these cases. Results: A total of 2173 patient responses (1229 patients) were collected. The CAT model was able to reduce the question burden by a mean of 9.33 questions (45.1%). Higher CAT-predicted scores correlated strongly with higher actual scores (r = 0.99; intraclass correlation coefficient = 0.99). The mean difference between the CAT-predicted score and the actual PROM score was 0.48 of a point on a scale of 0 to 100. Conclusion: The use of CAT systems, in conjunction with electronic PROMs, can accurately predict outcome scores for IKDC PROMs, while dramatically decreasing the number of questionnaire items needed for any given patient. By decreasing questionnaire burden, clinicians and researchers can potentially increase patient participation and follow-up in both clinical assessments and research trials.