Studies have shown that intra-articular glucocorticoid injection treatment for knee synovitis has a better outcome in resting patients than in mobile patients. One reason for this observation might be that rest retards steroid resorption, causing an enhanced local treatment effect.
To study drug resorption and the impact on hormone production in the hypothalamic-pituitary-adrenal axis after intra-articular glucocorticoid administration, with and without postinjection rest.
Twenty patients with rheumatoid arthritis and knee synovitis were randomised to either 24 hour bed rest or normal activity after intra-articular glucocorticoid treatment with 20 mg triamcinolone hexacetonide (THA). Serum levels of THA, cortisol, and adrenocorticotropic hormone (ACTH) were followed during 2 weeks.
Short term and reversible decreases in serum cortisol and ACTH levels (p<0.001) were seen, without any significant differences between resting and mobile patients. The THA levels increased similarly in both groups, with the median serum peak seen after 8 hours.
Immobilisation does not appear to retard glucocorticoid resorption after intra-articular administration. Further studies are therefore needed to clarify the mechanism behind the beneficial effects of rest after intra-articular glucocorticoid treatment for knee synovitis.