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Steroid injections for OA may accelerate disease progression


Evelyn Lewin


16/10/2019 4:08:24 PM

A new paper outlines the risks of intra-articular corticosteroid injection and advocates for the prior use of imaging.

Examining knee
The paper’s authors believe doctors should think twice before opting for joint injection, saying that patients with no or mild OA on radiograph should be ‘closely scrutinised’.

Osteoarthritis (OA) commonly affects the hip and knee joints, and intra-articular corticosteroid injections are frequently performed as a treatment.
 
But the procedure is not without risks.
 
A new paper, which reviewed the outcomes of 459 injections, has identified four potential adverse events associated with this procedure:

  • accelerated OA progression in 6% of patients
  • subchondral insufficiency fractures in 0.9%
  • complications of osteonecrosis in 0.7%
  • rapid joint destruction, including bone loss, in 0.7%
Professor David Hunter is a rheumatology clinician researcher at the University of Sydney School of Medicine and co-Chair of the development working group for the RACGP’s Guideline for the management of knee and hip osteoarthritis.
 
He told newsGP he was not surprised by the first finding, saying the potential deleterious effects of corticosteroid injections are ‘an increasing area of concern and more clinicians should be aware of it’.
 
‘I think the more recent data that probably needs to be known, and that isn’t well known, is that corticosteroid injections do appear to accelerate the rate of progression [of OA] in people with pre-existing OA,’ he said.
 
In terms of the other documented adverse events, Professor Hunter said it can be hard to determine whether injections may lead to those outcomes, such as fractures, or whether such fractures were the underlying reason for a patient’s initial presentation of pain.
 
Either way, he believes it is imperative that GPs know the potential risks of such procedures, as they are ‘very widely used’ in clinical practice.
 
The authors of the paper presented reasons as to why they believe these injections can lead to such outcomes. For example, they noted that in vitro and animal research has found that corticosteroids can have negative effect on cartilage.
 
‘The action by which corticosteroids are chondrotoxic is complex, but it seems to affect cartilage proteins, especially aggrecan, type II collagen, and proteoglycan, by mediating protein production and breakdown,’ the authors explained.
 
In light of these results, the authors believe doctors should think twice before opting for joint injection, saying that patients with no or mild OA on radiograph should be ‘closely scrutinised’ before such treatment is given.
 
Professor Hunter agrees doctors should weigh up risks and benefits when considering this treatment. He said appropriate management of OA includes the use of analgesic agents like anti-inflammatories, along with heat, ice and potentially adjuvant physiotherapy.
 
But he still thinks there is a role for joint injection.
 
‘If you absolutely, positively need to, by all means consider a corticosteroid injection – but it’s not what we would typically do in the first instance in a flare of pain for knee OA,’ Professor Hunter said.

David-Hunter-Article.jpg
Professor David Hunter said the potential deleterious effects of corticosteroid injections are of ‘increasing concern and more clinicians should be aware of it’.

Another issue flagged by the paper is the role of imaging before performing such injections, with the authors advocating its use for a number of reasons.
 
‘Given the relative ease of performance and the low cost of radiography, there should be a low threshold to obtain radiographs before performing an intra-articular corticosteroid [IACS] injection, as the intervention may affect the disease course [ie it may result in accelerated progression],’ the authors wrote.
 
They also believe it is important to identify a subchondral insufficiency fracture before corticosteroid injection, as they state that glucocorticoids may inhibit the healing process of such a fracture.
 
Furthermore, they say performing such injections in the presence of a subchondral insufficiency fracture may worsen clinical function. That is because an injection could result in decreased joint pain, which may then lead to increased weight bearing ‘and possible acceleration of subchondral insufficiency fracture to joint collapse’.
 
However, current guidelines in Australia do not suggest radiological imaging prior to joint injection for OA.
 
According to the Guideline for the management of knee and hip osteoarthritis, which was updated in July 2018, OA is typically diagnosed clinically, and the role of imaging is ‘limited’ and ‘not needed’ but could be considered for atypical presentations.
 
Professor Hunter stands by these guidelines, saying he worries about the consequences of routinely imaging all patients pre-injection.
 
‘To do that routinely for everybody who presents with knee pain is going to cause a lot of unnecessary imaging and downstream interventions and their consequences,’ he said.
 
He believes the authors’ recommendations for imaging are ‘a little bit overblown’ and says GPs need to be ‘very cautious’ about its overuse.
 
‘Knee pain flares are a very common manifestation of osteoarthritis and if we image people every time they had a knee pain flare, it would add extraordinary expense and potentially have deleterious consequences in terms of unnecessary interventions,’ he said.
 
Instead of routine imaging, he believes doctors should rely on their clinical skills.
 
‘For a person who presents with an exacerbation of knee pain in the context of knee OA, flares are a very common problem, so use your diagnostic acumen,’ he said.
 
‘Take a good history, do a good examination [and] if you’re very worried about one of those other very rare events then by all means get imaging, but knee flares are a common part and parcel of a person having knee OA, so manage that appropriately.’

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