Minimum joint space width demonstrates higher inter- and intra-observer reliability than Kellgren-Lawrence grading in knee osteoarthritis.
Monty S Khela, Tiana Lee, Kellen L Mulford et al.
✦ AI-curated · Sources linked
In 30 seconds
This Level III systematic review compared inter- and intra-observer reliability of Kellgren-Lawrence (KL) grading and minimum joint space width (mJSW) measurement on knee radiographs. It included 24 studies covering 10,394 radiographs. Inter-observer reliability was generally higher for mJSW than for KL grading: mean ICC = 0.82 ± 0.17 for mJSW versus mean κ = 0.72 ± 0.17 for KL. Similar trends were reported for intra-observer reliability. Expertise, semiflexed posteroanterior/Rosenberg views and atlas-guided training were associated with improved reliability; AI-assisted systems performed comparably to expert raters.
Key findings
- Inter-observer reliability was higher for mJSW (mean ICC = 0.82 ± 0.17) than for KL grading (mean κ = 0.72 ± 0.17).
- Experts and AI-assisted systems outperformed trainees/non-experts for both radiographic assessment metrics.
- Semiflexed posteroanterior/Rosenberg views and atlas-guided training were associated with improved reliability.
Why it matters
Radiographic assessment of knee osteoarthritis depends on reproducible interpretation. The review suggests that quantitative mJSW measurement may provide more consistent readings than ordinal KL grading, while rater expertise, imaging view and structured training also influence reliability. These findings help frame how radiographic measures and assessment methods may affect consistency across studies and clinical evaluations.
What to keep in mind
The review reports reliability across included studies, but the abstract does not provide pooled estimates or detail the variability in study methods and populations.