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AB0345 Osmic acid synovectomy; is there still a need for this treatment?
  1. C. Mercieca1,
  2. G. Bezzina2,
  3. A. A. Borg2
  1. 1Rheumatology, Bristol Royal Infirmary, Bristol, United Kingdom
  2. 2Rheumatology, Mater Dei Hospital, Birkirkara, Malta


Background Osmic acid synovectomy has been shown to be an effective and safe treatment for patients with chronic knee inflammatory arthritis unresponsive to intra-articular glucocortcoids and DMARDs. With the introduction of biologics and improvement in DMARD therapeutic strategies the utility of osmic synovectomy may be questioned.

Objectives To ascertain the efficacy, safety and quality of life in patients with inflammatory arthritis and inflammatory osteoarthritis in current practice

Methods This was a prospective study of patients who underwent osmic synovectomy of the knee in 2011-2012. All patients had knee effusions and had failed intra-articular glucocorticoid injections. Patients were assessed by a clinician and filled a number of questionnaires (Lequesne, WOMAC, pain scores visual analogue scale (VAS) at rest, weight bearing and on movement) at baseline, 1 month, 3 months and 6 months post-injection.

Results Twenty four patients (14 females, 10 males) were recruited. The mean age was 36 years (SD 13.4, range 34-82). Nine patients had rheumatoid arthritis (RA) (5 were on a biologic and DMARDs, 4 on DMARDs only), four had psoriatic arthritis (PsA) (all were on DMARDs and a biologic) and 11 had inflammatory osteoarthritis (OA). The median time of knee pain and swelling was 12 months (range 3-120). One patient had bilateral osmic acid synovectomy. Six patients had previously undergone the procedure, 3 of the same knee. No complications were reported

Mean VAS pain scores at baseline, 1 month and 6 months were as follows; at rest 46.9, 29.3, 21.5 (p=0.001), on weight bearing 62.1, 44.8, 40.4 (p=006) and on movement 54.4, 45.8, 32.2 (p=0.005). The WOMAC at baseline, 1 month and 6 months were; 52.2, 39.4 and 36.9 (p= 0.005) and Lequesne scores were 15.5, 12.4 and 9.4 (p=0.001). Patients with inflammatory arthritis showed a more significant improvement compared to those with OA. Knee swelling was present in 8 patients at 1 month and 10 patients at 6 months.

Conclusions Osmic acid synovectomy of the knee is a safe and efficacious therapy as evidenced by the marked response in pain, swelling and quality of life. The main advantages include the sustained fast acting response and a minimally invasive procedure which allows immediate initiation of rehabilitation. Despite the availability of more effective biologic therapy osmic acid synovectomy is still a useful adjuvant therapeutic option particularly in cases of monoarthritis or knee inflammatory arthritis resistant to intra-articular glucocorticoids, DMARDs and biologics. Its efficacy in inflammatory OA is also very useful and should be considered more often as a treatment option.

References Bessant R, Steuer A, Rigbi S, Gumpel M. Osmic acid revisited: factors that predict a favourable response. Rheumatology 2003;42:1036–1043

Disclosure of Interest None Declared

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