The Changi General Hospital (CGH) carries out viscosupplementation for patients with knee osteoarthritis through intra-articular hyaluronic acid injections, using Synvisc or Synvisc-One (containing hylan G-F 20). Some patients on Synvisc are susceptible to flare or pseudoseptic reaction on repeated therapy. It was proposed to procure Synolis V-A intra-articular injection as an alternative for these patients.

A rapid health technology assessment was carried out on the following PICO elements: Population - Patients with knee osteoarthritis, Intervention - Synolis V-A, Comparator - Synvisc, Outcomes - Risk of flare reaction/pseudoseptic arthritis.

Based on a preliminary scan of the literature, a simple search was conducted for all publications on Synolis V-A, and for reviews on the risk of flare/pseudoseptic reaction with Synvisc.

No publications reporting on flare/pseudoseptic reactions with Synolis V-A were found. There are limited case series of patients treated with Synolis V-A, with most evidence coming from a prospective post-marketing surveillance case series, which showed reduced pain and functional impairment at 6 months. Adverse reactions were rare. CGH's own small trial of Synolis V-A did not show any flare reactions.

In contrast, flare/pseudoseptic reactions with Synvisc are an established phenomenon. A systematic review of randomized controlled trials documented one flare reaction among 381 patients (0.26 percent) in Synvisc compared to none in patients receiving other hyaluronan products. Small case series of patients on Synvisc showed incidences of flare reaction of 21 percent (in repeat treatment) to 27 percent. CGH's own experience is that flare occurs in 4.7 percent of patients on Synvisc.

It is reasonable for the hospital to stock an alternative for patients who show repeated flare reactions to Synvisc. The limited evidence base is not a barrier to using Synolis V-A as an alternative, given the local experience.