gms | German Medical Science

Objectives: The primary aim of this study was to evaluate the inter- and intra-observer reliability of four commonly used radiological grading systems, using two different frontal radiographic views (AP and Rosenberg).

The secondary aim of this study was to compare the correlation of knee OA severity, as indicated by each grading scale, with patient reported outcome measures.

Methods: This study included 100 patients who had undergone both AP and Rosenberg X-ray views of the knee and evaluated using four radiological grading systems. These included Kellgren & Lawrence (K&L), International Knee Documentation Committee (IKDC), Ahlbäck and Fairbank. Evaluations were performed by two observers, independently, at two separate time points, 8 weeks apart. The data was then statistically analysed and inter- and intra-observer reliability calculated.

Results and Conclusion: A significant difference was found between AP and Rosenberg views for all four grading systems (p<0.001). Both inter- and intra-observer reliability was highest for IKDC (0.79 and 0.86 respectively) and lowest for Fairbank (0.20 and 0.27 respectively). No statistically significant correlation was found between any grading system and the Oxford knee score (OKS).

IKDC was found to be the most reliable grading system and Fairbank was the least. The Rosenberg view was overall more sensitive at detecting severe OA than the AP view. Radiological findings did not correlate with patient reported symptoms (OKS).