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Radiosynovectomy in Haemophilic Arthropathy

Musculoskeletal · 3 min read

In haemophilia, repeated bleeding into one joint inflames the synovium, and the inflamed synovium bleeds again. Radiosynovectomy (RSV) breaks this cycle: a β-emitting colloid injected into the joint scars the synovium from the inside. The World Federation of Hemophilia (WFH) recommends it in its 2020 guidelines as the first-line non-surgical synovectomy.

Why the joint keeps bleeding

  • Blood in the joint leaves iron in the synovium, and the iron drives inflammation (synovitis).
  • The inflamed synovium grows fragile new vessels, which bleed more easily.
  • One “target joint” bleeds again and again, most often the knee, ankle or elbow. Over years this destroys cartilage and bone: haemophilic arthropathy.
  • RSV scars the synovium and closes its capillaries, so the joint bleeds less.

When to offer it

SituationCriterion
Chronic synovitisLasting more than 3–6 months, confirmed on ultrasound or MRI
Recurrent bleeds3 or more bleeds into the joint in 6 months despite factor replacement (EANM); WFH uses 2 or more
TimingAs early as possible, before arthropathy is established
Patients with inhibitorsNot a barrier: RSV still works, and is especially useful because bleeds are harder to control

Inhibitors are antibodies that some patients make against the factor VIII or IX they are given. They develop in about a quarter to a third of people with severe haemophilia A, and fewer with haemophilia B. They neutralise factor concentrate, so it no longer stops bleeding. Inhibitors are never given as treatment; they are a complication that changes which drug covers the procedure.

Management in haemophilia

  1. Plan with the haematologist: every patient needs cover against bleeding from the needle puncture, so the haematologist writes the cover plan before the day.
  2. No inhibitors: give a dose of the missing factor intravenously just before the puncture, usually within the hour, so the level peaks during the injection. Haemophilia A gets factor VIII; haemophilia B gets factor IX. WFH advises one dose per injection.
  3. With inhibitors: the antibodies neutralise factor concentrate, so a factor dose would not stop a bleed. Give a bypassing agent instead, just before the puncture: recombinant factor VIIa, or aPCC (activated prothrombin complex concentrate). These start clotting by a route that skips factors VIII and IX. RSV itself works just as well in these patients; only the bleeding cover changes.
  4. On emicizumab: emicizumab is a weekly to monthly injection under the skin that prevents bleeds in haemophilia A, with or without inhibitors. It is an antibody that does the job of factor VIII by bringing factors IX and X together. It does not raise factor VIII levels, so the haematologist decides whether extra cover is needed for the puncture. aPCC is avoided alongside emicizumab because of a risk of clotting in small vessels (thrombotic microangiopathy).
  5. Choose the agent: 90Y for adult and adolescent knees; 186Re for ankles, elbows and younger children’s knees. There is no fixed activity for children; published series used half the adult activity.
  6. After the injection: splint the joint for about 48 h. EANM advises continuing intensified factor replacement for 3 months, because the healing synovium bleeds easily.
  7. Rehabilitation: return to activity gradually, with no heavy exercise or weight bearing straight away.
  8. If bleeds continue: repeat RSV after at least 6 months, up to 3 times; if it still fails, consider surgical synovectomy.

What to expect

OutcomeResult
Benefit70–90% of patients have fewer bleeds, less pain and better function
BleedsDown by about two-thirds in a 500-procedure series over 38 years
Surgery avoidedOnly about 6% later needed arthroscopic synovectomy or joint replacement
Best jointsAnkle, then elbow, then knee
Cancer riskNo increase seen in 2,412 treated patients

Fuller version, with activities by joint and the step-by-step checklist: Radiosynovectomy therapy guide.

Take home
  • RSV breaks the bleed → synovitis → bleed cycle by scarring the synovium. It is the first-line non-surgical synovectomy in haemophilia.
  • Offer it early: chronic synovitis, or 2–3 bleeds into one joint in 6 months despite factor replacement. Inhibitors are not a barrier.
  • Every patient needs cover for the puncture: factor just before the injection, or a bypassing agent if they have inhibitors. Repeat after 6 months if needed, up to 3 times.
Sources
  1. Kampen WU, Boddenberg-Pätzold B, Fischer M, et al. The EANM guideline for radiosynoviorthesis. Eur J Nucl Med Mol Imaging. 2022;49(2):681-708.
  2. Srivastava A, Santagostino E, Dougall A, et al. WFH guidelines for the management of hemophilia, 3rd edition. Haemophilia. 2020;26 Suppl 6:1-158.
  3. Rodriguez-Merchan EC, De la Corte-Rodriguez H, Jimenez-Yuste V. Radiosynovectomy in haemophilia: long-term results of 500 procedures performed in a 38-year period. Thromb Res. 2014;134(5):985-90.
  4. Rodriguez-Merchan EC. Radiosynovectomy in haemophilia. Blood Rev. 2019;35:1-6.
  5. Tena-Sanabria ME, Rojas-Sato YF, Castañeda-Resendiz JC, et al. Treatment with radiosynoviorthesis in hemophilic patients with and without inhibitor. BMC Pediatr. 2020;20(1):173.
  6. Infante-Rivard C, Rivard GE, Derome F, et al. A retrospective cohort study of cancer incidence among patients treated with radiosynoviorthesis. Haemophilia. 2012;18(5):805-9.
  7. Bieńkowski K, Kocemba M, Kunikowska J. Joints and needles: summary of radiosynoviorthesis. Reumatologia. 2025;63(3):174-81.
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