In the records of the New York Orthopaedic Dispensary and Hospital there are the histories of twentythree cases of sacro-iliac tuberculosis treated by operative fusion. Until 1919 the therapy employed was conservative, with rest in bed, heliotherapy and supportive measures. After 1920 arthrodesis of the sacro-iliac joint was always the method of choice unless the condition of the patient was such that operation would be immediately dangerous. This study is limited to those cases in which treatment was by operation.
Of the twenty-three patients, thirteen were females and ten were males. The average age at onset was twenty-three years, with four patients younger than 15. The right side only was affected in 52 per cent (twelve patients). Both sides were affected in two patients.
It is felt that sacro-iliac tuberculosis is one of the rare forms of tuberculosis and usually indicates a widespread infection in the body. Seventy