Two-year results of radiosynovectomy in knee-joints of hemophilic patients using locally developed P-32 colloid

Full text: The aim of this study was to assess the effects of radionuclide treatment of haemophilic arthropathy of knee joints refractory to conventional medical therapy with the locally developed P-32 colloidal suspension in Argentina, and compare the results with those of chemical synovectomy, and to assess the cost/ effective aspects of radiosynovectomy. It may be noted that other imported colloidal radiopharmaceuticals like Y-90 citrate, Re-186 sulfide or Er-160 citrate are expensive in Argentina. On the other hand we have the technology to prepare Ho-166 macro-aggregates in Argentina, but the radiopharmaceutical has not been approved for use on humans by the country's regulatory authorities. Radiosynovectomy was performed using P-32 colloid in 58 male hemophilic patients, ages ranging from 4-52 years. Nine patients had re-treatments either in the same or in the contralateral knee, making it a total of 67 procedures in the study. In adults, a dose of 37-74 mCi was used, while 33% of this dose was used in children between 2-6 years, 50% in children between 6-10 years and 75% in children between 10-16 years of age. Patients with Grades II and III arthropathies were included in the study. Informed consents from adults and from the parents of children were obtained. Patients with large Bakers cyst, grade IV arthropathy, infection in the skin around the joint area and bleeding at the time of the procedure were excluded from the study. Documentation clinical history and AHF therapy was done in all cases. All patients underwent three phase bone scans before therapy and after therapy at 1, 3 6, 9 and 12 months. If required, joint aspiration was carried out. P-32 Bremsstrahlung emission was used in the scintigraphies for early and late imaging to confirm the presence or absence of leakage. All patients were subjected to immobilization of the treated joints and relative rest for a period of 72 hours following therapy. There were no local or systemic adverse effects following treatment. No leakage of radioactivity was detected in any of our patients. Intraarticular Rifampicin procedure required frequent injections. The follow-up evaluation demonstrated significant improvement of joint motion, diminished knee volume and less requirement and frequency of the use of Anti-haemophilic Factors (AHF) in 80% of patients subjected to radiosynovectomy (54 /67 procedures), thus lowering treatment costs. Remission Indices (rate of change of lesion activity over time) calculated over the treated joints using sequential Tc-99m MDP soft tissue scintigraphy revealed significant reduction of lesion activity objectively. Overall it has been observed that one intra-articular knee radiosynovectomy procedure using P-32 colloid in patients with haemophilic arthropathy could provide relief from symptoms for a period of 3-6 months. We have found radiosynovectomy to be safe and cost-effective and recommend its use as an alternate therapeutic procedure where availability of AHF is difficult and expensive. (author)