A study on atypical Kashin-Beck disease: an endemic ankle arthritis

Background To study the epidemiological characteristics of atypical Kashin-Beck disease cases without characteristic hand lesions such as interphalangeal joint enlargement and brachydactyly and the characteristics of ankle joint lesions. Methods We investigated Kashin-Beck in the endemic villages in Heilongjiang Province. The patients were judged according to the "Diagnosis of Kashin-Beck Disease" ( WS/T 207-2010). The severity of foot lesions was judged based on the changes of X-ray images. Residents of non-Kashin-Beck disease area were selected as normal controls in Jilin Province. Results A total of 119 residents over 40 years old were surveyed in a natural village in the non-endemic area. A total of 1190 residents over 40 years old were surveyed in 38 endemic areas of Kashin-Beck disease. A total of 710 patients with Kashin-Beck disease were detected, including 245 patients with grade I, 175 patients with grade II, 25 patients with grade III, and 265 atypical patients. Among all investigated patients, 92.0% (653/710) had ankle joint changes, and it was 80.0% (196/245) in grade I patients and 95.4% (167/175) in grade II. Varying degrees of ankle joint changes were found in both grade III and atypical patients. The grade of Kashin-Beck disease was correlated with the degree of ankle joint change (P < 0.001), and the correlation coefficient r(s) = 0.376. Atypical Kashin-Beck disease patients in mild and severe endemic area of Kashin-Beck disease were younger than those with typical Kashin-Beck disease. Conclusions We found a correlation between the degree of ankle joint change and the grade of Kashin-Beck disease. The higher the grade of Kashin-Beck disease, the more serious the change of the ankle joint.