Study finds intra-articular lidocaine cuts rescue opioid use in dogs

A newly published clinical trial reports that intra-articular lidocaine, given before shoulder arthroscopy in dogs, reduced the need for intraoperative rescue analgesia compared with saline, with or without the addition of adrenaline. The study, published June 30, 2026, in Frontiers in Veterinary Science, evaluated dogs undergoing arthroscopic treatment for shoulder osteochondritis dissecans at the University of Perugia in Italy. Both active-treatment groups outperformed control, and the lidocaine-plus-adrenaline group showed the longest delay before the first sufentanil bolus was required. (frontiersin.org)

The work builds on a long-running question in both human and veterinary arthroscopy: whether putting local anesthetic directly into the joint can meaningfully blunt perioperative pain without creating unacceptable safety tradeoffs. The authors note that intra-articular local anesthetics are widely reported in human arthroscopy, and that adrenaline is commonly used to help control bleeding and improve visualization. But, until now, its combined effect with lidocaine on perioperative pain had not been studied in dogs undergoing shoulder arthroscopy. (frontiersin.org)

In the new trial, 24 dogs contributed 27 joints, with three dogs treated bilaterally in separate surgical sessions. Cases were limited to shoulder osteochondritis dissecans without concurrent tendon or ligament injury, and dogs with severe osteoarthritis or marked synovitis were excluded. Joints were randomized to lidocaine alone, lidocaine plus adrenaline, or saline. The primary readout was intraoperative nociceptive response, assessed by hemodynamic changes that triggered IV sufentanil rescue if heart rate, respiratory rate, or systolic blood pressure rose more than 20% over baseline. Both lidocaine groups had significantly lower rescue opioid requirements than controls, with odds ratios for avoiding a sufentanil bolus of 6.28 for lidocaine alone and 8.45 for lidocaine plus adrenaline relative to saline. (frontiersin.org)

The timing data are also clinically relevant. In the control group, most rescue boluses clustered around trocar insertion, which the paper identifies as one of the most painful parts of the procedure. In contrast, dogs given lidocaine plus adrenaline did not require their first bolus until T10, later than the other groups. The authors interpret that pattern as evidence of a pre-emptive analgesic effect, while cautioning that the specific contribution of adrenaline remains uncertain because the study was not designed to directly measure joint residence time, bleeding control, or lidocaine pharmacokinetics in the shoulder. (frontiersin.org)

There wasn't much independent expert commentary available at publication, but the study does fit with prior canine literature from related arthroscopy settings. A 2015 paper on intra-articular lidocaine plus adrenaline in dogs undergoing elbow arthroscopy reported no signs of systemic toxicity and investigated plasma exposure specifically to address safety concerns. More recent veterinary literature has also explored other intra-articular analgesic combinations during canine arthroscopy, reinforcing that the concept is clinically active, even if protocols vary by joint, drug choice, timing, and study design. (sciencedirect.com)

Why it matters: For veterinary professionals, this paper strengthens the case for intra-articular lidocaine as a useful add-on in multimodal anesthesia for canine shoulder arthroscopy, particularly when trying to reduce intraoperative opioid rescue during predictable pain peaks. That said, the findings should be applied with restraint. This was a relatively small, single-center study, the experimental unit was the joint rather than strictly the dog, and postoperative pain was not assessed with validated scoring tools. The authors also explicitly flag the unresolved issue of potential chondrocyte toxicity, which has been described in human and comparative literature and remains a key consideration whenever intra-articular local anesthetics are discussed. In practical terms, the study is more supportive of selective protocol refinement than of a wholesale standard-of-care shift. (frontiersin.org)

Another point for clinicians is that adrenaline's role may extend beyond analgesia. The paper notes its vasoconstrictive properties could theoretically reduce systemic absorption of lidocaine and prolong local action, while human arthroscopy literature has used epinephrine to improve the surgical field by limiting bleeding. Still, those advantages remain inferential here, not directly proven in this canine shoulder cohort. For surgeons and anesthetists, that means lidocaine alone now has clearer support than saline, while lidocaine plus adrenaline remains promising but not yet fully differentiated on outcome data that matter most in practice. (frontiersin.org)

What to watch: The next developments to watch are larger controlled studies with validated postoperative pain scoring, longer follow-up on joint health, and more direct comparisons that test whether adrenaline adds meaningful clinical benefit beyond lidocaine alone in shoulder arthroscopy cases. (frontiersin.org)