New variables for measuring joint space width to evaluate knee osteoarthritis.

Area of Science:

• Radiology
• Orthopedics
• Medical Imaging Analysis

Background:

• Assessing radiographic features of knee osteoarthritis (OA), particularly joint space narrowing, is crucial for monitoring disease progression.
• Quantitative analysis of joint space narrowing can provide more precise evaluation of knee OA.
• Traditional methods may not fully capture the nuances of OA-related joint space changes and their impact on function.

Purpose of the Study:

• To quantitatively analyze joint space narrowing in knee OA using two novel variables: average joint space width (aJSW) and articulate angle (AA).
• To evaluate the relationship between aJSW, AA, knee function, and OA symptoms.
• To assess the utility of aJSW and AA as potential new metrics for knee OA assessment.

Main Methods:

• Two variables, aJSW and AA, were measured on X-ray films using a web-based radiology viewer (Cedara I-Reach™ 4.1.1).
• Measurements were performed on 50 knees from 41 patients with knee OA enrolled in the Shanghai OA Study.
• Kellgren-Lawrence (K-L) grade, Western Ontario and McMaster Universities OA Index (WOMAC) scores, and additional questionnaire data were collected and analyzed.

Main Results:

• aJSW showed significant correlations with K-L grade, WOMAC pain and disability scores, and various functional limitations including kneeling, sitting cross-legged, squatting, and defecating in a squatting position.
• AA demonstrated correlations with K-L grade, WOMAC disability, and defecating in a squatting position.
• K-L grade also correlated with functional limitations and WOMAC scores, but aJSW exhibited stronger associations with OA-related disabilities.

Conclusions:

• The average joint space width (aJSW) is a sensitive quantitative variable that closely correlates with knee OA symptoms and functional impairments.
• aJSW appears to be more sensitive in detecting knee OA-related disabilities compared to the Kellgren-Lawrence (K-L) grade and articulate angle (AA).
• aJSW represents a promising new variable for the quantitative evaluation and monitoring of knee osteoarthritis.