Classification of articular cartilage lesions of the knee at arthroscopy.

Classification systems for articular cartilage lesions in the knee have been based primarily on the appearance and severity of damage to the articular cartilage. Each of these systems has deficiencies in the documentation of articular cartilage abnormalities. This article proposes a new classification system for articular cartilage lesions in the knee. This system incorporates multiple parameters such as appearance, depth of involvement, area, clinical stage, and location of the lesion. A four-sector-mapping system allowing precise documentation of the location of articular cartilage lesions in the femorotibial joint is proposed. One numerical category is used to assess severity of a chondral defect. The use of these categories allows the surgeon to accurately grade and locate damage to the articular cartilage and its relationship to other concomitant intra-articular abnormalities. The proposed classification system has proven advantageous in communicating complex findings.