Objective performance tests assess aspects of function not captured by self-report in knee osteoarthritis

Area of Science:

• Orthopedics
• Rheumatology
• Geriatrics

Background:

• Knee osteoarthritis (OA) significantly impacts patient function, assessed through subjective reports and objective measures.
• Understanding the relationship between objective performance and self-reported function is crucial for comprehensive OA management and research.

Purpose of the Study:

• To investigate the association between objective physical performance tests and self-reported functional status in individuals with symptomatic and radiographic knee OA.

Main Methods:

• Analysis of baseline data from 101 participants (≥40 years) in the Osteoarthritis Registry of Biomarker and Imaging Trajectories (ORBIT) cohort.
• Utilized the Knee Injury and Osteoarthritis Outcome Score (KOOS) Pain and Activities of Daily Living (ADL) scales.
• Assessed objective function via timed single leg balance (SLB), 30-s sit-to-stand (30s STS), Timed-Up-and-Go (TUG), and 40-m fast-paced walk tests.
• Employed Pearson correlation coefficients and adjusted partial correlations to examine associations, controlling for confounders.

Main Results:

• Correlations between objective performance tests and self-report measures were weak to modest (absolute values ranging from 0.24 to 0.39 for KOOS ADL).
• Adjusted partial correlations showed similar trends to crude correlations, indicating robustness of findings.
• Mean performance values included SLB 20.1s, 30s STS 11.7 stands, TUG 9.4s, and 40m Walk 27.6s.

Conclusions:

• Self-reported function in knee OA patients demonstrates weak to modest correlation with objective functional assessments.
• Objective performance tests provide unique insights into physical function beyond subjective reports.
• Incorporating objective measures of functional status is recommended for future OA clinical trials.