Treatment of synovial sepsis is challenging in the best of circumstances. A Canadian study evaluated the use of medical-grade honey (MGH) following endoscopic or tenoscopic debridement and lavage to treat synovial sepsis in three horses [Terschuur, JA.; Coomer, RPC.; McKane, SA. Administration safety of medical-grade honey (MGH) in septic synovial structures in horses: 3 cases. The Canadian Journal of Veterinary Research 2023; 887, pp. 153-156].
Medical-grade honey is known for its antimicrobial and anti-inflammatory properties, particularly for use in wound care and second intention healing. It is believed that MGH causes bacterial desiccation by its high osmolarity, low pH and associated release of hydrogen peroxide. This study sought to evaluate its efficacy and biocompatibility in synovial structures. Honey was warmed prior to infusion to dissolve crystals.
One case involved digital flexor tendon sheath sepsis of the right hind limb of an 11-year-old Welsh pony mare. Following tenoscopic debridement, 10 ml of sterile Manuka honey was infused into the sheath with 200 mg of amikacin. Along with bandage changes every two to three days, the mare continued on procaine penicillin and gentamycin for five days. She returned to full work nine months later, qualifying for the Welsh National Championships.
A second case involved a 6-month-old Thoroughbred colt with a puncture wound into the radiocarpal joint. Arthroscopic lavage and debridement were performed, followed by infusion of 10 ml of sterile Manuka honey and 200 mg amikacin, and bandaging. At follow-up 18 months post-op, the colt did not demonstrate any lameness.
The third case centered on an 11-year-old Warmblood mare with a laceration over the lateral tarsometatarsal joint and a medial wound that communicated with the tarsal sheath. The mare presented with Grade 3 lameness (AAEP scale). Radiographs revealed a displaced, comminuted articular fracture of the head of the fourth metatarsal bone, which necessitated surgical removal. Both wounds were debrided and lavaged, medicated with 5 ml of sterile Manuka honey and bandaged. Both procaine penicillin and gentamycin were administered for three days post-op, yet microbial culture revealed resistant mixed organisms that finally responded to five days of enrofloxacin. At the two-year follow-up, the horse was still sound and in normal use and exercise.
Previous human studies have demonstrated that use of Manuka honey did not elicit antimicrobial resistance when exposing E. coli, MRSA, Pseudomonas, and S. epidermis to sub-lethal concentrations of the honey for as long as 28 days. Other studies have identified chrysin from honey that “attenuates NLRP3 inflammasome signaling that reduces synovitis and release of IL-1B, IL-18, substance p, and calcitonin gene-related peptide.” Further studies also demonstrated that quercetin from honey is useful to suppress inflammation while also inducing transforming and insulin-like growth factors to promote chondrogenesis.
The authors concluded that administration of sterile Manuka honey into inflamed synovial cavities is safe and did not elicit adverse effects on these three cases.
