Canada - Hylan G-F 20 (Synvisc®) is an elastoviscous fluid containing hylan polymers, which are derivatives of hyaluronan (sodium hyaluronate). It is indicated for the treatment of pain caused by osteoarthritis of the knee in patients who have failed to respond adequately to conservative nonpharmacologic therapy and simple analgesics. Treatment involves intra-articular injection once a week for 3 weeks. The most commonly reported adverse incidents have been pain, swelling and effusion in the injected knee (1).

From March 1996 to January 2005, Health Canada received 31 reports of suspected incidents associated with Synvisc®; 23 were received in 2003-2004. In nine cases, the synovial fluid was not removed before each injection, and in five the course of injection was continued after the occurrence of adverse symptoms. Six of the 23 recent reports described patients who had pain, walking disability and knee swelling with or without effusion after the third injection of the first course. Two of these 23 patients were admitted to hospital.

The occurrence of post-injection effusion may be associated with the number of injections (1). There have been reports in the literature of pseudosepsis (2). In affected patients, pseudo-sepsis typically occurs after more than one injection. Sepsis or pseudogout should be ruled out. Mononuclear cells are present in the synovial fluid (2). Although the cause of pseudosepsis is not fully understood, there is increasing evidence to suggest an immunologic mechanism (2).

Health care professionals should be aware of these possible adverse incidents and encouraged to follow the labelled procedure, including aspiration of synovial fluid before each injection (1). Patients should be alerted of the occurrence of such events, and those who have severe inflammation of the joint after an injection should be fully evaluated (3).

Extracted from: Canadian Adverse Reaction Newsletter, Volume 15, Issue 2, April 2005.

References

1. Synvisc Hylan G-F 20 [prescribing information]Ridgefield (NJ): Genzyme Biosurgery. Revised 2004 Nov 15.

2. Goldberg VM, Coutts RD. Pseudoseptic reactions tohylan visco supplementation: diagnosis and treatment. Clin Orthop 2004;(419): 130-7.

3. Bernardeau C, Bucki B, Liote F. Acute arthritis after intra-articular hyaluronate injection: onset of effusions without crystal. Ann Rheum Dis 2001;60(5): 518-20.