X-ray image characteristics and related measurements in the ankles of 118 adult patients with Kashin-Beck disease

Background Kashin-Beck disease (KBD) is a chronic, degenerative osteoarthropathy that causes severe skeletal deformation. Although many researchers have proven that almost all KBD patients who showed an increaseing proximo-distal gradient had radiographic abnormalities of the ankle, few detailed description of radiographic changes in the ankles of patients with KBD has been reported, especially for variable measurements of ankle changes. The purpose of this study was to demonstrate the radiographic characteristics of the ankles of adult KBD patients. Methods One hundred and eighteen adult KBD patients from september to October 2010 in Rongtang county in China were examined with lateral radiographs of the right ankle. The morphological abnormalities in the talus, calcaneus, navicular bone, distal tibia, and joint space were analyzed, and the calcaneus length, height, length-height ratio, tuber angle, front angle, plantar angle, and distal tibia anteroposterior (AP) length were measured using Riepert's method. Results Eighty-one patients (68.6%) had abnormal ankle radiographs; 72 (88.9%) patients had talus changes, 69 (85.2%) patients had calcaneus changes, 28 (34.6%) patients had navicular bone changes, and 48 (59.2%) patients had distal tibia changes. For 118 KBD patients, the average calcaneus length was 7.4 cm, height was 4.3 cm, and the length-height ratio was 1.7. The calcaneus tuber angle was 28.2°, front angle was 38.0° and the plantar angle was 74.2°. The distal tibia anteroposterior length was 4.05 cm. Compared with 50 normal adults (control group), significant differences were found for the calcaneus length, the calcaneus length-height ratio, and the distal tibia AP length. Conclusions Patients with KBD have characteristic abnormalities on ankle radiographs; talus depression and deformity, calcaneus shortening deformity, and distal tibia deformity with AP length widening were the most typical changes.