Fig. 6

A-B. Method used to measure the area of the subchondral bone affected by the giant cell tumor of the bone: (A) The width of epicondyle to middle of joint (A) and the width of affected subchondral area (a) were measured in the anteroposterior plane; (B) The whole width of joint (B) and the width of affected subchondral area (b) were measured in the lateral plane; (a × b/A × B) × 100 =% of the subchondral bone area affected by tumor