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

Abstract

Objective: 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.

Methods: 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).

Results: 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.

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