Do Not Throw Out the Radiographs! Radiographic Disease Severity as a Prognostic Biomarker for the Onset of Frequent...

To enable interventions aimed at preventing the onset of frequent knee osteoarthritis (OA) symptoms and their sequelae, effective screening methods are required. Conventional radiographs are accessible and inexpensive; consequently, they have the potential to identify those at high risk of developing symptoms. Thus, we aimed to determine whether radiographic severity is prognostic of frequent symptoms at 12- and 48-month follow-up visits.

We studied knees from participants of the Osteoarthritis Initiative without frequent symptoms at the baseline visit. Posteroanterior semiflexed knee radiographs were obtained at the baseline visit and scored for Kellgren-Lawrence (KL) grade (0-4). Frequent knee symptoms were defined by self-report at baseline, month 12, and month 48 follow-up visits. We conducted knee-based logistic regression, using generalized estimating equations to account for correlation between knees within a person, to assess if baseline KL grade was associated with incident frequent symptoms (at 12 and 48 months).

The study included 5653 knees (3407 participants). The incidence of frequent symptoms at 12 months by baseline KL grades were 12.4% (KL 0), 15.6% (KL 1), 18.6% (KL 2), 24.7% (KL 3), and 37.2% (KL 4). Relative to KL 0, the odds of frequent knee symptoms at 12 months were elevated for KL 1 (odds ratio [OR] 1.30, 95% CI 1.05-1.61), KL 2 (OR 1.61, 95% CI 1.32-1.96), KL 3 (OR 2.31, 95% CI 1.82-2.92), and KL 4 (OR 4.18, 95% CI 2.69-6.48). The results at 48 months were similar.

Radiographic OA severity should be considered a potential prognostic biomarker to identify individuals at high risk of developing knee symptoms.