Severe Acute Localised Reactions after Intra-Articular Hyaluronic Acid Injections; a Narrative Review and Physician’s Guide to Incidence, Prevention, and Management of These Adverse Reactions.

BackgroundHyaluronic acids are commonly used in osteoarthritis. Whilst adverse events are infrequent, the most common is pain and swelling of the joint.MethodsA narrative review of the incidence and causes of SALR with insights into the prevention and management of SALR.ResultsSALR refers to the onset of acute arthralgia, associated swelling, erythema and motion restriction, after the intra-articular injection of HA. The onset of symptoms is between 4 hours and several days. SALR appear to be immunological responses to the HA and related to poor injection techniques.DiscussionThis literature review identifies that the incidence of SALR following intra-articular injection of HA is relatively low but is not rare. Thus, clinicians using intra-articular HA injections can expect to see patients with SALR and should be prepared to diagnose and treat SALR. The risk of SALR appears to be independent of the source of HA (avian or bacterial fermentation) and the use of crosslinking of the HA product.ConclusionIntra-articular HA injections are relatively common treatments for the symptoms of osteoarthritis, where primary interventions have been ineffective. Whilst the risk of complications from such injections is low, both mild and more severe acute localised reactions do occur. The reactions can be mitigated by the careful selection of injection portal and the use of ultrasound guidance. Once the differential diagnosis of septic arthritis is excluded, the management of a SALR will generally consist of reassurance and simple analgesia, with more severe cases requiring non-steroidal anti-inflammatory medication or intra-articular corticosteroids.What is known about this topicHyaluronic acids have been used in the management of osteoarthritis for over three decades. Whilst adverse events are infrequent, the most common is pain and swelling of the joint, which when severe are termed severe acute localised reactions (SALR) or pseudo-sepsis.What this study addsThis paper provides the injecting physician with a narrative review of the incidence and causes of SALR, insights into the prevention and a discussion of the management.How might this affect research practice or policy?This information will allow clinicians to mitigate the risks of triggering a SALR and provides a clear pathway for management if such an event occurs. Additionally, it informs the creation of specific policies around the use of HA injections.