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Adjunctive acupuncture improves postoperative pain control and early functional recovery after stifle joint surgery in dogs: a prospective randomized controlled clinical trial

This prospective randomized controlled trial demonstrates that adjunctive acupuncture, when combined with multimodal analgesia, significantly improves postoperative pain control and early functional recovery in dogs undergoing stifle joint surgery without causing adverse events.

Original authors: shuman Liu, Han Zhang, Zhihui Hao, Gebin Li, Kai Fan, Zhankui Yuan, Shuaiyu Wang

Published 2026-07-30

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CC BY 4.0

Original authors: shuman Liu, Han Zhang, Zhihui Hao, Gebin Li, Kai Fan, Zhankui Yuan, Shuaiyu Wang

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine the world of veterinary medicine as a high-stakes rescue mission. When a dog breaks a leg or needs a complex knee repair, the surgery is just the first step; the real challenge begins when the anesthesia wears off. Just like us, dogs feel pain, but they can't say, "Ouch, that hurts!" or ask for a specific kind of medicine. Instead, vets have to play detective, watching for subtle clues like whining, hiding, or refusing to walk. To solve this mystery, vets usually use a "team approach" called multimodal analgesia. Think of this like a superhero squad where different medicines (painkillers, anti-inflammatories, and nerve blockers) work together to tackle pain from every angle. But even with a whole team of drugs, sometimes the pain is still too loud, and the dog stays grumpy and stiff. This is where a very old, very different kind of healer enters the scene: acupuncture. For centuries, humans have used tiny needles to tap into the body's own energy pathways to stop pain. But does this ancient trick actually work for our four-legged friends, or is it just a nice story? That's the big question scientists at China Agricultural University decided to test.

The researchers set up a fair fight to see if adding acupuncture to the standard pain-killing squad could make a difference for dogs recovering from stifle (knee) surgery. They gathered 16 dogs who needed knee operations and split them into two teams. One team got the standard "superhero squad" of medicines. The other team got those same medicines plus a special treatment: a series of tiny, sterile needles placed in specific spots on their legs and backs, some of which were gently zapped with a tiny, safe electric current (electroacupuncture) to wake up the body's natural painkillers. The scientists then played the role of super-observers, checking the dogs' pain levels, how much they could bend their knees, and even their heart rates every few hours for three days after the surgery.

The results were pretty exciting for the acupuncture team. The dogs that got the needles were noticeably less in pain at specific times. When checked 12 hours and 48 hours after surgery, they scored much lower on the "pain scales" (specifically the CMPS-SF and CSU-CAPS scores) than the dogs who only got the drugs. It was like the acupuncture dogs were the calm, relaxed ones at a party, while the others were still a bit jittery. Even more interesting, when the vets gently moved the dogs' knees to see how much it hurt, the acupuncture dogs were much more tolerant just 3 hours after waking up. They also seemed to bounce back faster in terms of swelling; the change in their knee size from before surgery to 48 hours after was significantly better for the needle group. Their knees also started bending more freely by the 72-hour mark.

However, the story isn't a magic cure-all. The study found that the acupuncture didn't change how much the dogs limped, nor did it significantly change the levels of a specific pain-fighting chemical in their blood (beta-endorphin) in a way the scientists could prove with certainty. Also, only one dog in the acupuncture group needed extra "rescue" pain medicine, compared to the control group, but the difference wasn't statistically huge enough to say it was a guaranteed rule. The researchers also checked for side effects and found none; the needles were safe, and no dogs got hurt or sick from the treatment.

So, what's the takeaway? The study suggests that adding acupuncture to the standard pain management plan is a safe and helpful extra tool. It's not replacing the medicine, but rather acting like a secret weapon that helps the body feel better faster and move more easily in the first few days after surgery. While the scientists can't say it's a perfect solution for every single dog or that it works by a specific chemical mechanism they fully understand yet, the evidence points to a clear benefit: a little bit of ancient wisdom, combined with modern medicine, might just be the key to a happier, less painful recovery for our canine friends.

Technical Summary: Adjunctive Acupuncture for Postoperative Pain Control and Functional Recovery in Canine Stifle Surgery

Problem Statement
Postoperative pain management remains a significant challenge in veterinary orthopedic surgery, particularly for dogs undergoing stifle joint procedures (e.g., for patellar luxation or cranial cruciate ligament disease). Inadequate pain control can lead to delayed functional recovery, impaired mobility, and adverse neuroendocrine responses. While multimodal analgesia (combining opioids, NSAIDs, local anesthetics, etc.) is the current standard, it may not provide optimal relief and carries risks of adverse effects such as gastrointestinal disturbances and sedation. Although acupuncture has shown analgesic potential in human and veterinary medicine, high-quality prospective clinical evidence regarding its efficacy as an adjunctive therapy for postoperative pain in dogs is limited. Furthermore, objective biomarkers associated with acupuncture-mediated analgesia, such as serum $\beta$ -endorphin, have not been sufficiently investigated in this context.

Methodology
This study was designed as a prospective, randomized, controlled clinical trial conducted at the Veterinary Teaching Hospital of China Agricultural University between June 2021 and March 2022.

Subjects: Sixteen client-owned dogs (ASA status I–II) requiring unilateral stifle surgery were included in the final analysis (8 per group) after four exclusions.
Intervention:
- Control Group: Received a standardized multimodal analgesic regimen consisting of lidocaine constant-rate infusion, carprofen, gabapentin, and cryotherapy for 72 hours postoperatively.
- Acupuncture Group: Received the same multimodal regimen plus adjunctive acupuncture. Treatments were administered immediately after extubation and every 24 hours for 72 hours.
- Acupuncture Protocol: Specific acupoints (ST-34, SP-10, GB-34, KID-10, Baihui, ST-36, GV-14, KID-3, BL-23) were stimulated. Manual stimulation was used for most points, while Baihui and ST-36 received electroacupuncture (2/100 Hz dense-disperse wave, 0.5–1.5 mA) until mild muscle contraction was observed. Each session lasted 20 minutes.
Outcome Measures: Assessments were conducted at baseline (T0) and at 3, 6, 12, 24, 36, 48, 60, and 72 hours post-extubation.
- Primary Outcomes: Pain intensity via Glasgow Composite Measure Pain Scale–Short Form (CMPS-SF) and Colorado State University Canine Acute Pain Scale (CSU-CAPS).
- Secondary Outcomes: Joint manipulation scores, lameness scores, stifle circumference, range of motion (ROM), physiological variables (temperature, heart rate, respiratory rate, blood pressure), rescue analgesia requirements, and serum $\beta$ -endorphin concentrations (measured at T0 and T72).
Statistical Analysis: Data were analyzed using independent-samples t-tests or Mann–Whitney U tests for between-group comparisons at specific time points, and linear mixed-effects models for repeated measures.

Key Results

Pain Scores: Dogs in the acupuncture group exhibited significantly lower pain scores compared to controls at specific intervals:
- CMPS-SF: Significantly lower at 12 hours ( $P=0.050$ ) and 48 hours ( $P=0.038$ ).
- CSU-CAPS: Significantly lower at 24 hours ( $P=0.028$ ).
- Joint Manipulation: Significantly lower scores at 3 hours ( $P=0.010$ ), indicating reduced sensitivity to touch.
Functional Recovery:
- Stifle Circumference: The change in circumference from baseline to 48 hours (T48–T0) was significantly greater (indicating less swelling) in the acupuncture group ( $P=0.015$ ).
- Range of Motion (ROM): The change in ROM from baseline to 72 hours (T72–T0) was significantly greater in the acupuncture group ( $P=0.021$ ).
- Lameness: No significant differences were observed between groups at any time point.
Physiological Variables:
- Respiratory Rate: Significantly lower in the acupuncture group at 12 hours ( $P=0.002$ ) and 24 hours ( $P=0.050$ ).
- Blood Pressure: Significantly lower in the acupuncture group at 24 hours ( $P=0.015$ ).
- Temperature and Heart Rate: No significant differences were detected.
Biomarkers and Safety:
- $\beta$ -Endorphin: While serum $\beta$ -endorphin levels increased in both groups, the difference in the magnitude of increase between groups did not reach statistical significance ( $P=0.056$ ).
- Rescue Analgesia: Only one dog in the acupuncture group required rescue analgesia, compared to the control group (no specific count provided for controls, but the difference was not statistically significant).
- Adverse Events: No acupuncture-related adverse events were observed. Transient anesthesia-related complications occurred in both groups and resolved with supportive care.

Significance and Claims
The authors conclude that adjunctive acupuncture, when combined with a standardized multimodal analgesic protocol, improves postoperative pain control and selected indicators of early functional recovery in dogs undergoing stifle joint surgery. Specifically, the study demonstrates that acupuncture reduces pain scores during the critical early postoperative window (up to 48 hours) and facilitates better early recovery metrics, such as reduced joint swelling and improved range of motion.

The paper posits that acupuncture is a safe and effective complementary intervention for perioperative pain management in veterinary clinical practice. The observed reductions in respiratory rate and blood pressure in the acupuncture group are interpreted as consistent with reduced sympathetic activation and improved comfort. However, the authors remain modest regarding the mechanism, noting that the lack of statistical significance in $\beta$ -endorphin levels may be due to the small sample size and biological variability, and that circulating levels may not fully reflect central neurochemical changes.

The study acknowledges limitations, including the small sample size, the difficulty of complete blinding in acupuncture trials, heterogeneity in surgical procedures, and the short 72-hour observation period. Consequently, the authors suggest that while the findings are promising, larger-scale studies with standardized procedures and longer follow-up periods are necessary to fully clarify the role of acupuncture in canine postoperative rehabilitation.

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