Inter-observer reliability of the arthroscopic quantification of chondropathy of the knee

Background: Several scoring systems have been proposed in order to quantify the degree of cartilage damage observed by arthroscopy of the knee in patients with osteoarthritis. Objective: To evaluate the inter-observer reliability of five different scoring systems of arthroscopic evaluation for chondropathy in osteoarthritis of the knee and to evaluate the utility of a training session between different observations on these scoring systems. Methods: Videotapes of knee arthroscopies on five patients with osteoarthritis demonstrating different levels of severity of cartilage damage of the medial tibiofemoral compartment were analyzed by nine observers prior to (pre-training evaluation) and 2 months after a 6 h training session (post- training evaluation) by the following scoring systems: (1) cartilage deterioration by a 100 mm visual analogue scale (VAS), (2) overall assessment of degeneration in the entire medial compartment (cartilage, meniscus, osteophyte) using a 100 mm VAS, (3) French Society of Arthroscopy (SFA) Scoring System, (4) SFA Grading System, (5) American College of Rheumatology (ACR) Scoring System. Results: At the pre-training evaluation, the SFA grading system produced the highest coefficient of reliability (r = 0.94), the other systems recording levels of ≤ 0.80. At the post-training evaluation, the coefficient of reliability was r > 0.80 for four of the five scoring systems, with lack of improvement in the ACR Scoring System. Conclusion: There was an improved and acceptable inter-observer reliability for at least 2 months follow-up in four of five evaluated scoring systems of arthroscopically graded osteoarthritis of the knee following a training session. A scoring system using a 100 mm VAS may produce the best inter- observer reliability. These results show that scoring chondropathy is possible and demonstrate the importance of training in the analysis of articular cartilage breakdown.