Arthroscopic validation of radiographic grading scales of osteoarthritis of the tibiofemoral joint

OBJECTIVE. The purpose of this study was to use the Kellgren-Lawrence, Ahlback, and Brandt grading scales to correlate radiographic grade of osteoarthritis with the actual degree of articular cartilage degeneration within the tibiofemoral joint in patients with chronic knee pain. SUBJECTS AND METHODS. The study group consisted of 125 patients with symptomatic osteoarthritis of the tibiofemoral joint. For all patients, standing anteroposterior radiographs of the knee were obtained before arthroscopic knee surgery. Each articular surface of the tibiofemoral joint was graded at arthroscopy. Two radiologists retrospectively reviewed the knee radiographs without knowledge of the arthroscopic findings to determine the presence and severity of osteoarthritis of the tibiofemoral joint using the Kellgren-Lawrence, Ahlback, and Brandt grading scales. Correlation coefficients describing the relation between grade of osteoarthritis and severity of articular cartilage degeneration were calculated for each grading scale. RESULTS. The correlation coefficients for the Kellgren-Lawrence, Ahlback, and Brandt grading scales were 0.49, 0.41, and 0.56, respectively. The differences between the correlation coefficients for the Kellgren-Lawrence and Ahlback grading scales and the correlation coefficients for the Brandt and Ahlback grading scales were statistically significant (p < 0.05). Many patients with no radiographic findings of osteoarthritis had significant articular cartilage degeneration within the tibiofemoral joint. CONCLUSION. The Kellgren-Lawrence and Brandt grading scales were equally effective in defining the presence of and estimating the severity of osteoarthritis of the tibiofemoral joint but had only a moderately strong correlation with the actual degree of articular cartilage degeneration.