Re-evaluating the need for hospitalization following synovectomy using Yttrium-90 silicate.

In 51 patients treated with Yttrium-90 (Y-90) synovectomy for rheumatoid (inflammatory) arthritis (IA) and OA of the knee we found that decreased retained knee activity (RKA) and increased extra-articular activity in lymph nodes and liver are more likely to be found in IA than OA and following bilateral knee injections. Joint inflammation, as assessed by radionuclide blood pool scan but not by SF white cell count, correlates with decreased RKA and increased activity in lymph nodes. Intra-articular steroid had no significant effect on retention or extra-articular uptake. Strict hospital immobilization improves RKA of Y-90 in IA but not in OA. Y-90 synovectomy in OA shows good RKA and low extra-articular uptake. We recommend strict immobilization following Y-90 synovectomy, particularly in IA patients and/or those with high joint blood flow.