Radiosynovectomy in the therapeutic management of arthritis

Abstract

Radiosynovectomy is a well-established therapy in arthritis and involves an intra-articular injection of small radioactive particles to treat a synovitis. In Europe, frequent indications are rheumatoid and poly-arthritis. Especially in Germany radiosynovectomy is the second common therapy in Nuclear Medicine with about 40,000-60,000 treated joints per year. In Spain, USA, Turkey, Argentines and Philippines the therapy is more use in hemophilic arthritis with excellent results. Especially in developing countries with low availability of clotting factors, the radiosynovectomy represent a cost effective therapeutic option for repeated bleedings in hemophilic arthropathy. The special focus in these countries is maintaining of mobility and work ability. Often only the knee and medium joints (ankle, elbow and shoulder) are treated using yttrium-90, rhenium-186 or phosphorus-32. However, in rheumatoid arthritis most common affected joints are the fingers. For the treatment in these small joints, erbium-169 is necessary. Unfortunately, erbium-169 is only available in Europe. Further indications for radiosynovectomy are osteoarthritis and the articular effusion after joint replacement. The reported response rates in rheumatoid and poly-arthritis range from 60% to 80% depends from the stage of previous arthrosis. The best effectiveness of therapy was observed in hemophilic arthritis with response rate of 90% and significant reducing of bleeding frequency. The therapy is well-tolerated with low rate of side effects. In respect of the specific uptake of particles in the synovia and short range of beta radiation, the radiation exposure outside the joint is very low. The radiosynovectomy has efforts in comparison to surgical synovectomy: it's a minor intervention with low costs; and simultaneous treatments of multiple joints or treatment in short intervals are possible. The presented paper summarized the published papers and reports our own experiences in >15,000 treated joints.

Keywords: Erbium-169; hemophilic arthritis; osteoarthritis; rhenium-186; rheumatoid arthritis; yttrium-90.

Figure 1

Typically in rheumatoid arthritis and poly-arthritis a proliferation of synovia with increasing numbers of macrophages was observed (publishing with approval by CicBio)

Figure 2

In radiosynovectomy small particles with a size >2 μm were applied intra-articular and have a homogeneous distribution in the joint cavity (publishing with approval by CicBio)

Figure 3

Within 2 days there is a complete uptake of radio-colloids in the synovia with phagocytosis in macrophages and other inflammatory cells (publishing with approval by CicBio)

Figure 4

Long-term the radiation leads to fibrosis of inflammatory synovia with reducing of effusion and hyperperfusion. Additional, a release of inflammatory enzymes is observed (publishing with approval by CicBio)

Figure 5

Typical blood pool phase of a patient suffer from rheumatoid arthritis. Sign of arthritis in left knee, both shoulders, left elbow, both wrist and metatarsophalangeal I, in these joints a radiosynovectomy is indicated. Additional tendovaginitis in the 5th finger of the right hand is appearing

Figure 6

Scan 2 h after technetium-99m-methylene diphosphonate of the same patients as Figure 5. Signs of arthrosis in all metacarpophalangeal's, but the blood pool phase is negative in these joints and so there is no indication for radiosynovectomy

Figure 7

Ultrasound of right knee in a patient with osteoarthritis and a large baker cyst's

Figure 8

Using of grasp-forceps for fixation of the injection needle during radiosynovectomy in knee to reduce the radiation exposure to finger pulp significantly