The effect of local injection of methylprednisolone acetate on the hypothalamic-pituitary-adrenal axis among patients with greater trochanteric pain syndrome.

Greater trochanteric pain syndrome (GTPS) is a common clinical entity for which the most effective treatment is local corticosteroid injection (LCI). There are no studies on the effect of LCI among patients with GTPS on the hypothalamic-pituitary-adrenal axis. The present study recruited nonselected patients diagnosed with GTPS. After consenting, participants received low dose (1 μg) of adrenocorticotropin hormone (ACTH) stimulation test at 09:00. Immediately following the test, participants received a LCI of 80 mg of methylprednisolone acetate at the greater trochanteric region. The ACTH stimulation test was repeated 1, 2, 4, and 6 weeks following the LCI. Cortisol samples were obtained at just prior to (basal) and 30 min (post-stimulation) following every ACTH stimulation test. Serum cortisol levels of <500 μmol/l obtained 30 min following the ACTH stimulation test were considered evidence of secondary adrenal insufficiency. The study enrolled 22 patients, 21 of whom completed participation. There were 19 female participants (~90%), and mean age of all the participants was 55.2 ± 8.6 years. Four participants showed evidence of secondary adrenal insufficiency, which was observed only at weeks 1 and 2 following the LCI. Mean serum cortisol level among these four participants 30 min following the ACTH stimulation test was 354 μmol/l, with a range of 268-430 μmol/l. LCI of 80 mg of methylprednisolone acetate in the greater trochanteric area among patients with GTPS was associated with transient secondary adrenal insufficiency in ~20% of the patients, mainly 1 week following the injection.