Reassurance over equine joint injections after human study raises concerns

A human study into commonly used steroid joint injections has indicated they may speed up the deterioration caused by osteoarthritis — but a top vet has reassured owners the same effects are not usually seen in horses.

A research team from Boston University discovered that corticosteroid treatments, previously thought to be safe, may be harmful to some patients, causing serious complications.

Feedback from a sample of patients injected in their hips or knees in 2018 revealed 8% suffered adverse affects — with 10% reporting problems after treatment in the hips and 4% in the knees.

Problems included accelerated progression of osteoarthritis and rapid destruction of joints.

In the journal Radiology, the study’s leading professor Ali Guermazi, chief of radiology at VA Boston Healthcare System, said the findings were serious enough that “critical considerations about the complications” should now become part of patient consent.

“We are now seeing these injections can be very harmful to the joints with serious complications such as osteonecrosis, subchondral insufficiency fracture and rapid progressive osteoarthritis,” he said. “Intra-articular corticosteroid injection should be seriously discussed for pros and cons.”

Corticosteroid injections are a very common treatment for horses suffering from joint pain, but orthopaedic surgeon and British Equine Veterinary Association (BEVA) council member Ollie Crowe suggested that horse owners need not be overly concerned.

He explained that joint disease varies enormously between species, and that while conditions such as traumatic arthritis occur in horses, diseases such as rheumatoid arthritis do not.

“Whilst all treatments have some associated risk, the complications reported following intra-articular corticosteroids in knee and hip osteoarthritis in people do not appear to be seen in horses,” he said.

“The evidence of collapse of the bone that supports cartilage has been shown not to occur in equine joints and the progressive deterioration of cartilage may be more a sign of progression of disease rather than an effect of the medication.”

He added that the sensitivity to drugs varies widely between species, but noted it was “interesting” that humans involved in the study were given a dose of 40mg triamcinolone as standard, which was 10 times the amount vets would normally administer to their patients.

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“Triamcinolone has also been shown to protect cartilage from some of the harmful effects of inflammation at the dose rates that we use in clinical cases,” he said, adding that the study also used steroid and anaesthetic combined, which has been shown to increase some of the toxic affects of steroids.

He added that another possible influence on the findings was that humans were likely to be treated when the disease is in a much later stage than when it is identified in equines, leading to a poorer outcome.

“In summary, while we need to be aware of the risks of the treatments and procedures that we perform, it is important to balance those against benefits. In horses, where applied to carefully diagnosed disease, especially in the early stages, joint medication can be an invaluable and relatively safe tool,” Mr Crowe said.

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