Interobserver and Intra-Observer Reliability of a New Prognostic Classification for Foot and Ankle Diabetic Charcot Arthropathy

Abstract

Category: Diabetes; Ankle; Hindfoot; Midfoot/Forefoot; Other Introduction/Purpose: Diabetic Charcot arthropathy of foot and ankle is a devastating, progressive destruction of bone and joint integrity affecting one or more joints. Although several classification systems exist for Charcot arthropathy of foot and ankle depending on developmental stages or anatomic regions affected, the majority of these classifications are mainly descriptive, and none of these classifications specified the management or the outcome with relation to the classification stage. Recently, a new prognostic classification (Mansoura Classification) was published, however the reliability of such classification is still unknown. The aim of this study was to evaluate both interobserver and intra-observer reliability of Mansoura classification for foot and ankle Charcot arthropathy. Methods: Mansoura classification for foot and ankle Charcot arthropathy was presented to participants at an international foot and ankle course, then participants were given colored printed copy of the classification table (table 1) and diagrams. Thereafter, twenty cases of foot and ankle Charcot were presented to participants and they were asked to rate each case according to the classification. The level of experience of all the participants was collected and classified as less than 5 years, 5-10 years, 10-15 years, 15-20 years and more than 20 years. Furthermore, six raters who were specialized in foot and ankle surgery were asked to repeat the classification of the cases after three weeks from the initial evaluation. Kappa statistics was used to evaluate both interobserver and intra-observer reliability using STATA 14.2 program, and results were interpreted as 0.00-0.20 Slight, 0.21-0.40 Fair, 0.41-0.60 Moderate, 0.61-0.80 Substantial; and 0.81-1.00 Excellent. Results: Sixty-one participants with different level of experience completed the evaluation of the twenty cases of foot and ankle Charcot. The interobserver reliability for all participants was moderate (Kappa=0.5). Further analysis according to the level of experience based on the years of practice of orthopedic surgery showed similar moderate reliability (Kappa range 0.4 to 0.57). Intra-observer reliability was excellent for all six participants, Kappa range 0.81 to 0.93. Further analysis of the interobserver reliability of the former six raters who were specialized in foot and ankle surgery showed substantial reliability; Kappa=0.67. Conclusion: Mansoura classification for Charcot arthropathy of foot and ankle has an excellent intra-observer reliability. Although the overall interobserver reliability among orthopedic surgeons was moderate and comparable to other classifications, the interobserver reliability for orthopedic surgeons who were specialized in foot and ankle surgery was substantial. Therefore, Mansoura classification for foot and ankle Charcot has an acceptable reliability and could be promising in the evaluation and guiding the management of such cases.