Texas Equine Veterinary Association

www.texasequineva.com | 39 Synovial fluid analysis should include total WBC, total solids on refractometry, white blood cell differential and cytology, and synovial SAA. Any synovial structure that has parameters above normal should be treated as septic. BOX – NORMAL SYNOVIAL PARAMETERS TREATMENT Aer thorough exploration of the wound, the initial focus should be on treating and preventing synovial sepsis, infection of the collateral cartilages, or local cellulitis. Systemic antibiotics should be administered as one of the initial treatments. e sooner effective antimicrobials are on board, the more effective the therapy. Excede is not an effective choice for treating and preventing synovial sepsis. Broad-spectrum therapy that achieves high systemic and tissue levels is a better choice. Penicillin/ Gentamicin combination is the ideal therapy. Doxycycline/Metronidazole is an oral combination that can also be effective. In addition to systemic antimicrobials systemic anti-inflammatory drugs should be considered. A dose of phenylbutazone or flunixin is appropriate. Aer systemic therapy has been administered, treatment of the wound is next. Sharp debridement with a scalpel or tissue scissors can help remove contaminated tissue, however over aggressive debridement may limit the ability for primary wound closure or make a non-synovial injury a penetrating synovial injury. Heavy contamination can be addressed with wet-to-dry bandaging (frequently with a topical antimicrobial) and delayed primary closure. High tissue levels of antimicrobials can be achieved with a regional limb perfusion. Use of a dose dependent medication (Amikacin) with demonstrated efficacy against typical equine pathogens is preferred for intravenous regional limb perfusion. Local intra-synovial antimicrobial therapy is also common and recommended when distending synovial structures. When synovial structure involvement is identified, copious lavage is indicated. Ideally this lavage would be perfomed arthroscopically allowing for direct evaluation of joint cartilage, tendon sheath, or deep digital flexor tendon, as well as, identification of foreign bodies such as hair or dirt. When arthroscopy is not an option, through and through lavage with a pressure bag or pump can help to remove debris, inflammatory mediators, and dilute any additional infection. Non-synovial injuries should be attempted to close primarily. Light debridement and local anesthesia facilitate closure. A heavy bandage or foot cast can help to immobilize the repair and protect it from contamination in the local environment. Synovial injuries can be closed primarily post arthroscopy or if there is confidence all foreign material has been removed. Primary closure will reduce the healing time. When there is significant contamination, management of the wound as an open synovial structure is possible. Frequent lavage and repeat regional limb perfusion combined with systemic therapy and sterile bandaging can allow for the wound second intention wound healing. Punctures to the foot are difficult to bandage and protect well. A hospital plate shoe allows for a pad or aluminum plate that can be removed to allow access to the wound. Soaking of the foot in disinfectant (Clean-Trax) can reduce the microbial burden, but also desiccates the tissues. Use of medical maggots are an additional debridement strategy that can reduce the infected and necrotic tissue of foot injuries. FOLLOW-UP Depending on the structures involved, convalescent time can range from a couple weeks to several months. Standard hygiene practices are needed to prevent further contamination of the tissues, which can be challenging in the foot. Serial monitoring of the patient, synovial structures, and imaging, determine what therapies are needed and when exercise can resume. CONCLUSION Not all penetrating injuries to the foot are catastrophic. A 2018 study by Schiavo, et al (Vet Radiol Ultrasound. 2018 Nov) found that wounds with a lack of synovial sepsis carried a good prognosis with 60% returning to full athletic function and 40% sound but not yet back in work. In contrast, a 2014 study by Findley, et al (EVJ 2014 May) describes a lower prognosis with synovial penetration. In this study 44% of the horses were euthanized. 36% of horses returned to previous athletic levels. Aggressive treatment, soon aer injury is associated with better outcomes. Due to the development of new therapies, surgical techniques, and imaging, penetrating injuries to the foot can have an excellent outcome if treated early and appropriately. Patient presented with history of nail puncture to coronary band and mild lameness. Radiographs identified metallic foreign body fragments inside hoof capsule. CT imaging confirmed tract did not involve any synovial structures.

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