One of the best procedures to prevent haemarthrosis in haemophilia has been radioactive synovectomy (synoviorthesis). Since the first report of radioactive synovectomy in haemophilia of Ahlberg in 1971, (7) many centers adopted this procedure as the one of choice to, through fibrosing the synovial membrane, prevent further haemarthrosis. Since 1976 we have performed 119 such radioactive synoviorthesis in 110 patients with age from 3 to 40 years with a mean of 10 years of age, 71 of these patients were under 12 years of age. The knees were injected in 71 cases, elbow in 29 cases, ankles in 16 and shoulders in 3 cases. The clinical results of this procedure gives an 80% of excellent results with no further bleeding. In case of failure a new injection can be given in the same joint at a 6 month interval, or an injection for the same purpose in other joint. One of the criticisms against this method is the possible chromosomal damage induced by the radioactive material. In our center, 4 studies have been made in order to see whether these changes, in case of appearance, are everlasting and all have demonstrated that chromosomal changes are reversible. The radioactive material used in the 2 first studies was 189 Au. In 1978, 354 metaphases were studied with 61 ruptures, 17.23%, (non premalign) and 6 structural changes -considered premalign-, 1.69%. Any number below 2% is considered non dangerous. A further study was done in 1982, in the same group of patients with a result of 21 ruptures, 3.34% and
