For the grading of osteoarthritis in the knee, the
International Knee Documentation Committee (IKDC) system is regarded to have the most favorable combination of interobserver
precision and correlation to knee
arthroscopy findings. It was formed by a group of knee surgeons from Europe and America who met in 1987 to develop a standard form to measure results of knee ligament reconstructions. The
Ahlbäck system has been found to have comparable interobserver precision and arthroscopy correlation to the IKDC system, but most of the span of the Ahlbäck system focused at various degrees of bone defect or loss, and it is therefore less useful in early osteoarthritis. ==Other joints==