Perineural Dexamethasone Extends Pain Relief After Hip Replacement in Older Adults

Older adults undergoing total hip arthroplasty are particularly vulnerable to postoperative pain, opioid-related adverse effects, and metabolic disturbances after surgery. A randomized, double-blind trial now published in BMC Geriatrics by Tomasz Reysner, Bahadir Ciftci, Malgorzata Reysner and colleagues offers evidence relevant to that trade-off. The study compared two routes of administering the same dose of dexamethasone — a corticosteroid known to prolong the action of local anesthetics — as an adjunct to a pericapsular nerve group (PENG) block in patients aged 65 years or older scheduled for elective hip replacement under spinal anesthesia. The question was deceptively simple: does injecting the drug directly alongside the targeted nerves, rather than into a vein, keep the block working longer?

In the trial, all participants received a standardized regional anesthesia protocol including a PENG block with ropivacaine; the only difference between the two groups was whether 4 mg of preservative-free dexamethasone was added to the perineural injectate or given as 4 mg intravenously. This design isolated the effect of the route of administration on both analgesic duration and metabolic profile, since intravenous corticosteroid administration may increase postoperative glucose concentrations — a concern in older adults. The primary outcome was the time to the first rescue opioid analgesia within 48 hours after surgery.

The difference between the groups was striking. In the 60 participants included in the final analysis, the median time to first rescue opioid was 33.4 hours in the perineural dexamethasone group, with a 95% confidence interval extending from 15.8 hours to a value too high to estimate, compared with 12.3 hours (95% CI 11.4 to 13.2) in the intravenous group. Expressed as a hazard ratio, the likelihood of needing rescue opioids was 2.59 times higher in the intravenous group (95% CI 1.31 to 5.13; p = 0.0027).

Opioid consumption told the same story. Median 48-hour intravenous morphine-equivalent consumption was 0.4 mg (interquartile range 0.0 to 1.9) after perineural dexamethasone versus 2.4 mg (interquartile range 0.0 to 3.5) after the intravenous route. In practical terms, many patients who received the drug alongside the nerves needed little or no supplemental opioids at all during the first two days after hip replacement.

The metabolic findings, though exploratory, may prove to be the trial’s most consequential contribution. Because the study was powered for the analgesic endpoint, secondary analyses of glucose, inflammatory markers, motor function, and safety were prespecified but considered exploratory. Within that limitation, postoperative blood glucose concentrations were higher in the intravenous group, with an overall model-based mean difference of 22.29 mg/dL (95% CI 17.74 to 26.85) favoring the perineural route. For older surgical patients, a route of administration that delivers the same analgesic benefit while sparing the systemic metabolic profile could matter as much as the analgesia itself. The inflammatory markers neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio were also prespecified secondary outcomes in the trial.

Safety results were reassuring but bounded by the short follow-up. Motor function was comparable between the two groups, and no neurological complications or intervention-related adverse events were observed during the 48-hour follow-up period. The authors caution, appropriately, that the favorable glucose findings require confirmation in adequately powered studies.

The trial’s rigor is reflected in its prospective registration on ClinicalTrials.gov (NCT06789328, registered on 23 January 2025). The double-blind design, in which neither patients nor assessors knew which route of dexamethasone each participant received, strengthens confidence in the primary analgesic result. The standardized anesthesia protocol across both groups further supports the conclusion that the route of dexamethasone administration, rather than other factors, drove the observed difference in time to rescue analgesia.

Still, the core message stands on the primary endpoint alone: in older adults undergoing hip replacement, adding dexamethasone directly to the PENG block extended the median pain-free interval from 12.3 to 33.4 hours compared with giving the identical dose intravenously, while median opioid requirements over 48 hours remained very low in both groups. The sample size of 60 participants and the exploratory nature of the metabolic and safety analyses mean the findings should be interpreted with care.

If larger trials confirm the metabolic advantage, the choice of where to inject a corticosteroid adjunct could become a routine consideration in regional anesthesia protocols for older surgical patients — a small change in technique with the potential to reduce both opioid exposure and postoperative metabolic stress in a vulnerable population.

Subject of Research: Route of dexamethasone administration for PENG block analgesia in older adults undergoing total hip arthroplasty

Article Title: Time to first rescue opioid analgesia after perineural versus intravenous dexamethasone for PENG block in older adults undergoing total hip arthroplasty: a randomized double-blind trial

Article References: Reysner, T., Ciftci, B., Wieczorowska-Tobis, K., Perek, A., Marszałek–Buko, J., Pietraszek, P., Neumann-Podczaska, A., Mularski, A., & Reysner, M. (2026). Time to first rescue opioid analgesia after perineural versus intravenous dexamethasone for PENG block in older adults undergoing total hip arthroplasty: a randomized double-blind trial. BMC Geriatrics. https://doi.org/10.1186/s12877-026-08408-4

Image Credits: AI Generated

DOI: 10.1186/s12877-026-08408-4

Keywords: dexamethasone, PENG block, regional anesthesia, total hip arthroplasty, postoperative pain, opioid consumption, older adults, randomized trial, blood glucose, perineural, BMC Geriatrics, Time