Veterinarians sometimes apply medical-grade honey to infected, slow-healing postoperative, and necrotic topical wounds to support and accelerate the healing process. Researchers in the U.K. recently explored whether this approach could be used to manage intrasynovial sepsis after joint surgery.

For honey to be labeled and sold as medical-grade honey, it must undergo sterilization by gamma radiation (a form of electromagnetic radiation) to destroy potentially harmful microorganisms.

Medical-grade honey often contains manuka honey—made by honeybees that collect nectar from the manuka bush’s flowers—that inhibits bacterial growth and stimulates healing. Scientists have reported that bee defensin-1 (a protein type), long-chained sugar molecules, and honey’s other phenolic compounds (molecules produced by plants) further enhance its antimicrobial properties.

“While honey is relatively frequently used topically for wound treatment in horses, its use internally within joints, like in our study, is less common,” said Richard Coomer, MA, VetMB, CertES (soft tissue), Dipl. ECVS, MRCVS, RCVS & EBVS European specialist in equine surgery, of Cotts Equine Hospital, in Narberth.

Scientists have conducted extensive research on the antimicrobial properties of medical-grade honey in human joints, but Coomer said researchers still need to explore its use in veterinary medicine. Equine joint injuries are serious wounds practitioners often encounter, he added, and if not treated efficiently can lead to long-term pain and lameness, along with sepsis if the joint becomes infected.

He and his fellow researchers investigated the postoperative use of intrasynovial (applied within a joint structure) honey as an antimicrobial post-surgical treatment for synovial sepsis in three horses. Typically, veterinarians use antibiotics to treat sepsis within synovial structures, he said. The researchers placed medical-grade honey (containing manuka honey) directly within the synovial cavity after completing synovial sepsis surgery on the three horses.

“(This approach) was safe, no visible adverse effects were observed, and all three horses successfully recovered from their injuries and showed no signs of lameness in all three gaits,” said Coomer. “This was not a controlled study, and our findings do not show that honey better treats synovial sepsis than antibiotics. Therefore, we cannot conclude that placing medical-grade honey within the septic synovial structure is an alternative to conventional treatment.”

Medical-grade honey contains a mixture of novel antimicrobial compounds, he added, so there is no known microbial resistance to it in horses. Placing medical-grade honey directly within the synovial structure proved to be a safe adjunctive treatment in this study. “In clinics with high rates of antibiotic resistance, it could prove useful and should also provide a springboard for further prospective research with higher numbers of horses,” he said.  

The researchers concluded that the intrasynovial use of medical-grade honey in the three study horses was a beneficial secondary treatment after conventional surgery for septic arthritis. However, due to the small sample size, further research is needed to explore and assess the efficacy of medical-grade honey in equine articular cartilage.