Early Pain and Mobilization With Dexamethasone Versus Methylprednisolone Acetate in Adductor Canal Block for Knee Surgery: A Prospective Cohort Study

Abstract

Background. Dexamethasone phosphate is the most studied perineural corticosteroid, yet methylprednisolone acetate, a depot suspension, is also added to adductor canal blocks (ACB) without comparative evidence.

Objective. To compare early pain and mobilization after ACB with the two adjuvants.

Methods. Prospective single-center cohort, Malang, Indonesia (November 2024–April 2025). Fifty-three patients having knee surgery under spinal anesthesia received ACB with ropivacaine 0.5% 20 mL plus dexamethasone 10 mg (n=24) or methylprednisolone acetate 60 mg (n=29), chosen by the anesthesiologist. Outcomes were mobilization by 24 h (primary), Numerical Rating Scale (NRS) pain at 12, 24 and 48 h, and length of stay. Confounding was examined across all datasets consistent with the observed group-level margins.

Results. Mobilization by 24 h was 87.5% vs 62.1% (risk difference 25.4 points, 95% CI 1.5–45.3; Pearson p=0.037; Fisher p=0.059). Adjusted for age, surgery and sex, its odds ratio favored dexamethasone in 99–100% of datasets but reached significance in only 27–30%. Dexamethasone was associated with lower NRS at 12 h (2.71 vs 3.86; mean difference −1.15, −1.69 to −0.61) and 24 h (2.17 vs 3.24; −1.07, −1.41 to −0.73; both p<0.001), not at 48 h, and with less moderate pain at 12 h (8.3% vs 48.3%), significant in every age-adjusted model. Age distributions differed (exact p=0.006).

Conclusion. Earlier mobilization with dexamethasone was fragile and inseparable from age. Dexamethasone phosphate was associated with less pain than methylprednisolone acetate during the first 24 h; assessment was unblinded and rescue analgesia was not recorded. A randomized trial is required.