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19-04-2022 | Rheumatology | News | Article

Intramuscular glucocorticoid injection ‘considered effective’ for knee OA pain

Author: Laura Cowen

medwireNews: Intramuscular glucocorticoid injection is noninferior to intra-articular injection for reducing knee pain after 8 and 24 weeks in patients with knee osteoarthritis (OA), but may be inferior at 4 weeks, research shows.

In spite of this, Jos Runhaar (Erasmus MC University Medical Center Rotterdam, the Netherlands) and co-investigators say that the findings “suggest both types of injection should be considered effective strategies and that a shared decision-making process should take place between clinicians and patients with knee osteoarthritis when a glucocorticoid injection is indicated.”

The KIS trial involved 145 patients (mean age 67 years, 65% women) with symptomatic knee OA from 80 primary care general practices in the Netherlands.

They were randomly assigned to receive either an intramuscular (n=74) or intra-articular (n=71) injection of triamcinolone acetonide 40 mg; the intramuscular injection was given in the ipsilateral ventrogluteal region, while the intra-articular injection was administered to the knee joint.

In a per-protocol analysis, the researchers found that the mean KOOS pain score (range, 0–100; 0 indicates extreme pain) improved in both groups during the 24-week follow-up period, with the greatest improvements occurring 8 weeks after the intramuscular injection and 4 weeks after the intra-articular injection.

Furthermore, the mean improvements exceeded the minimal clinically important difference of 9.0 points for up to 12 weeks in each group.

At the primary analysis timepoint of 4 weeks, the mean KOOS pain score was 59.7 points in the intramuscular group and 64.7 points in the intra-articular group, giving an estimated mean difference of 3.4 points.

Runhaar and team report that this was not considered a noninferior difference because the lower limit of the 95% confidence interval exceeded the prespecified noninferiority margin.

By contrast, intramuscular injection was noninferior to intra-articular injection at both 8 and 24 weeks, with mean KOOS differences of 0.7 and 1.6 points between the two groups, respectively.

In addition, there was no significant difference between the two injection sites in the secondary outcomes of joint symptoms, function, stiffness, patient sport level, and quality of life during the 24-week follow-up period. In line with the pain results, intramuscular injection was most effective at 8 weeks, whereas intra-articular injection offered the greatest symptom relief after 4 weeks.

Thirty three percent of patients in the intramuscular group and 42% of those in the intra-articular group experienced adverse events (AEs), all of which were classified as nonserious.

The most common AEs were headache, occurring in 14% of the intramuscular group and 18% of the intra-articular group and hot flush, reported in 10% and 21%, respectively.

At 24 weeks, 6% of patients who received an intramuscular injection and 14% of those who received an intra-articular injection had received an additional intra-articular glucocorticoid injection.

Writing in JAMA Network Open, Runhaar and co-authors conclude: “This trial provides data for shared decision-making, taking into account the advantages and disadvantages of both types of injections.”

medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2022 Springer Healthcare Ltd, part of the Springer Nature Group

JAMA Netw Open 2022; 5: e224852

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