We previously reported the outcome of chromic phosphate-32(32 P) colloid synoviorthesis in 53 haemophilic patients with an average follow-up of 31 months. The purpose of the present study was the long-term follow-up of the same cohort on both clinical and radiographic features. Nine patients failed to attend the recall appointment. The mean follow-up for the remaining 44 patients (52 procedures) was 15 years (range, 14.6-15.5). The mean age at the time of reassessment was 31 years (range, 18-43). The haemarthrosis frequency was not statistically significant at the latest follow-up years compared with 31 months (0.8 vs 0.4 per week, P = .3). There was no significant change in the clinical severity of haemophilic arthropathy (P = .5). Most of the treated joints still are in stage III of Fernandez-Palazzi and Caviglia classification. There was a trend towards the radiologic deterioration of arthritis with nearly 50% of patients at Arnold-Hilgartner Stage V. 13% of patients underwent a total knee arthroplasty (TKA). The age at which the initial radiosynovectomy was performed was significantly higher in patients who had a TKA than those who had not (22 vs 15 years, P < .002). The bleeding control effect of 32P on the target joint remains over time; however, it did not appear to halt the progression of radiographic changes in haemophiliacs. It could delay the need for TKA if it performs at the right time. © 2019 John Wiley & Sons Ltd.