Minimum joint space width demonstrates higher inter-and intra-observer reliability than Kellgren-Lawrence grading in...

Area of Science:

• Radiology
• Orthopedics
• Medical Imaging Analysis

Background:

• Kellgren-Lawrence (KL) grading is a common method for assessing knee osteoarthritis severity.
• Assessing the reliability of radiographic interpretation is crucial for consistent clinical decision-making.
• Minimum joint space width (mJSW) offers a quantitative alternative for evaluating joint space narrowing.

Purpose of the Study:

• To systematically compare the inter- and intra-observer reliability of KL grading versus mJSW measurement on knee radiographs.
• To investigate factors influencing reliability, including rater type, radiographic view, and training.

Main Methods:

• Systematic review of studies reporting reliability for KL or mJSW on knee radiographs.
• Inclusion of data from PubMed/MEDLINE, Embase, Scopus, and Web of Science.
• Analysis of kappa (κ) and intraclass correlation coefficient (ICC) values, considering rater expertise, views, and atlas training.

Main Results:

• Twenty-four studies involving 10,394 radiographs were analyzed.
• mJSW demonstrated generally higher inter-observer reliability (mean ICC = 0.82) than KL grading (mean κ = 0.72).
• Expert raters and AI-assisted systems outperformed trainees; reliability improved with specific views and training.

Conclusions:

• Quantitative mJSW measurement generally exhibits superior reproducibility compared to KL grading for knee radiographs.
• Reliability is enhanced by rater expertise, standardized imaging protocols, structured training, and AI-assisted tools.
• mJSW should complement KL grading, especially with alignment measures, for improved consistency and clinical relevance in radiographic assessments.