B 군에서 관절면을 침범한 7예는 B-1군으로, 관절면을 침범하지 않은 24예는 B-2군으로 나누었다.
Among Group B, 7 cases that invaded the intra-articular surface were classified as Group B-1 and 24 cases that did not invade the intra-articular surface were classified as Group B-2.