Radiologists are calling for greater scrutiny of corticosteroid injections to the knee and hip for pain relief from osteoarthritis after new study findings reveal the practice is associated with accelerated disease progression and collapse of the affected joint in some patients.
They say the procedure may be more dangerous than previously thought and are calling for an overhaul of the informed consent process and a greater use of diagnostic imaging to identify patients who may be at increased risk for a negative joint outcome after a corticosteroid injection.
The study led by radiologist Professor Ali Guermazi from the Boston University School of Medicine in the US reviewed 459 patients from a single centre who received an intra articular corticosteroid (IACS) injection in 2018 – 307 into the hip joint and 152 into the knee joint.
Patients received between one and three injections over the course of the year and most (72%) had moderately severe osteoarthritis (KL grade 3).
Following their audit, researchers say they identified four main adverse joint findings in patients after IACS injections.
A total of 36 patients (8%) had adverse outcomes – the most common, affecting 6% of patients, was rapidly progressive osteoarthritis (RPOA).
The condition is synonymous with rapid loss of joint space on radiographs beyond the expected rate, say the authors.
Subchondral insufficiency fracture (SIF), which researchers say is typically found in a weight-bearing area and may be associated with cartilage loss and meniscal tearing, affected 0.9% of patients.
Patients typically present with acute pain, which gradually worsens for weeks without an identifiable trauma, the authors explain.
Warning that IACS injection in the presence of a SIF could result in decreased joint pain, potentially leading to increased weight-bearing and possible acceleration of the fracture, the investigators say the procedure could result in the eventual collapse of the articular surface.
Meanwhile, complications of osteonecrosis and rapid joint destruction, including bone loss each affected 0.7% of patients respectively.
Investigators say the findings warrant far more radiologic investigation before an injection is recommended.
The risk of rapidly progressive osteoarthritis, the authors say, may be especially high in people with acute changes in pain not explained on radiography, undiagnosed insufficiency fracture, and people with no or only mild OA at radiography.
This group of patient characteristics should lead to ‘careful reconsideration’ of a planned IACS say the investigators.
Clinicians should also consider obtaining a repeat radiograph before each subsequent IACS injection to evaluate for progressive narrowing of the joint space and any interval changes in the articular surface that can indicate subchondral insufficiency fracture or type 1 or 2 RPOA, they added.
Discussing the findings with the limbic rheumatologist and leading osteoarthritis researcher Professor David Hunter from the University of Sydney agreed that evidence suggesting steroids accelerate disease progression is increasing.
“They actually may not be as safe as people originally thought and some recent studies suggest the injections do increase the risk of more rapid disease progression. Theoretically they do so because they are toxic to the chondrocytes themselves,” he explained.
While he supported recommendations to inform patients of the risk of disease progression in some high-risk patients, he cautioned against an increased reliance on imaging.
“Their call for imaging essentially would be in anybody who has an increased intensity in pain, which is part and parcel of osteoarthritis. The challenge is that we know that the higher order imaging that they’re advocating clinicians do, particularly MRIs, increases rates of unnecessary interventions, particularly surgery. So I would be very cautious about following guidance that we should be doing more imaging in these sorts of people.”
Instead, Professor Hunter says clinical judgement is key.
“If someone does come along with a rapid escalation of pain on the background of osteoarthritis the most likely reason that that’s occurred is because they have got a flair of their osteoarthritis – but don’t ignore the possibility that it could be an insufficiency fracture or osteochondral fracture and try to make sure that, at least from a clinical standpoint, you’ve considered that.”
“The concerns about the potential toxicity is real, but the conclusion that we should do imaging as a standard part of our workup in a person who presents with an exacerbation of symptoms needs to be taken with a grain of salt – this is a group of radiologists recommending this in a radiology journal and I would not advocate that we follow that guidance,” he concluded.
The study is published in Radiology