Vascularity evaluation of the equine tarsocrural and proximal intertarsal joint septum, and comparative analysis of two arthroscopic transection techniques.

OBJECTIVE: To evaluate vascularity of the synovial membrane covered septum (SMS) separating the tarsocrural (TC) and proximal intertarsal (PIT) joints (Part 1) and compare two methods of transection, electrosurgical or Ferris Smith rongeur (FS rongeur) (Part 2). STUDY DESIGN: Experimental study. SAMPLE POPULATION: Part 1, 10 SMS (n = 5 horses). Part 2, six horses (n = 12 tarsi). METHODS: In part 1, SMS harvested postmortem were each divided into eight regions of interest (ROIs), processed for histology, and immunostained with anti-α-actin antibody for blood vessel identification. Vascular density was calculated for each ROI. Data was compared within and between horses. In part 2, six horses underwent TC arthroscopy. Each limb was randomly assigned to undergo either electrosurgical or FS rongeur SMS transection. SMS transection and total operative time were recorded. Intraoperative hemorrhage was scored. Data was compared between both techniques. RESULTS: Significant interindividual variations in SMS vascular density were detected (p = .02), but there were no differences among ROIs. No differences in the transection time were detected between electrosurgery (4.83 ± 0.54 min) and FS rongeur (4.33 ± 0.67 min). No differences were found in intraoperative hemorrhage scores between techniques. CONCLUSION: Vascularity within the SMS varies among horses but not within its regions. Electrosurgical or FS rongeur transection of the medial SMS during tarsocrural arthroscopy is a rapid technique and improves surgical access to the dorsal compartment of the PIT.

Feasibility of a disposable canister-free negative-pressure wound therapy (NPWT) device for treating open wounds in horses.

BACKGROUND: Wounds are among the most common medical conditions affecting horses and have a major economic impact on the horse industry. Wound healing in horses is distinct to that documented in other species, and often results in delayed healing and extensive scarring, with compromised functional and aesthetic outcomes. To date, there is no conventional method objectively proven to accelerate healing or to successfully prevent complications associated with second intention healing. Several effects of Negative Pressure Wound Therapy (NPWT) may be particularly useful to the management of wounds in horses. However, cumbersome designs of classic NPWT devices render them unsuitable for equine practice. A new lightweight, portable and disposable unit of NPWT (PICO®), should facilitate the use of this modality by equine practitioners. The aim of this study was to evaluate the feasibility of using this canister-free system to treat experimental open wounds in horses. RESULTS: No difficulties were encountered with the application or maintenance of the PICO® system during the ex vivo experiment or during the preliminary in vivo experiment conducted on intact skin. All horses readily tolerated the PICO® but difficulties with adhesion and seal prevented the completion of the experimental wound study despite the use of many adjunctive adhesives. CONCLUSION: The current PICO® dressing design is not suitable to be used as a dressing for open wounds in horses though the device is well tolerated by equine patients. A dressing with a wider adhesive edge, a superior adhesive and a more flexible pad would likely be better adapted to enable its future use in equine practice.

Choosing the Best Approach to Wound Management and Closure.

This article aims to help the practitioner by providing the tools to decide which type of closure or healing is best in a given situation. An overview of the main criteria and the different approaches to wound closure is presented. Each wound must be considered as a unique problem that requires a clinician to take into account all of its characteristics and limits to determine the best management approach.

Micro-computed tomography reveals high-density mineralised protrusions and microstructural lesions in equine stifle joint articular cartilage.

BACKGROUND: Stifle osteoarthritis (OA) lesions are most common in the medial femorotibial (MFT) compartment. Their characterisation and mapping will inform equine veterinarians towards an accurate diagnosis of OA. OBJECTIVES: Investigate and map micro-CT (µCT) changes in the hyaline articular cartilage (HAC) in the medial femoral condyle (MFC) and medial tibial plateau (MTP). STUDY DESIGN: Ex vivo cadaveric. METHODS: Stifles (n = 7 OA and 17 control [CO]) were retrieved from a tissue bank. The MFC and MFT were imaged with µCT. Regions of interest (ROIs) were cranial (MFCcr; MTPcr) and caudal (MFCca; MTPca) sites. In each ROI, µCT images were scored for HAC fibrillation, surface mineralisation and for the presence of high-density mineralised protrusions (HDMP). The lesions were mapped, and site-matched histology was performed. RESULTS: The microstructure of healthy and abnormal HAC was discernible on µCT images and confirmed with histology. HAC fibrillation was more prevalent (p = 0.019) in the MFCcr of the OA group (n = 7/7, 100%) when compared with the CO group (n = 7/17, 41%). Score 1 HAC surface mineralisation was more prevalent (p = 0.038) in the OA MFCca (n = 4/7, 57%) when compared with the CO group (n = 2/17, 12%). HDMP were heterogenous and hyperdense mineralised material protruding into the HAC and were more frequent (p = 0.033) in MFCs (n = 12/24, 50%) compared with MTPs (n = 5/24, 20%). Score 3 HDMPs were also more prevalent (p = 0.003) in the MFCcr (n = 7/24, 29%) compared with MFCca (n = 0/24, 0%) and in MFCs (n = 7/24, 29%) compared with MTPs (n = 3/24, 12.5%) (p = 0.046). MAIN LIMITATIONS: Clinical history was not available for all specimens. CONCLUSIONS: Equine HDMP and HAC surface mineralisation are imaged for the first time in the MFT joint. HAC fibrillation and erosion and HDMP are more frequent in the cranial aspect of the MFC. µCT images of OA in equine stifle joints provide a novel perspective of lesions and improve understanding of OA.

Use of next generation sequencing to investigate the microbiota of experimentally induced wounds and the effect of bandaging in horses.

OBJECTIVES: To use next generation sequencing to characterize the microbiota of horses during healing of skin wounds in two anatomical locations (body and limb) known to present different healing patterns; and to investigate the impact of bandaging on bacterial communities of skin wounds located on the limbs of horses. METHODS: Full-thickness skin wounds were created on the distal extremity of both thoracic limbs and on one lateral mid-thoracic wall of four healthy horses. Limb wounds were randomly assigned to bandaging or not. A full-thickness sample was collected with a biopsy punch from intact thorax and limb skin (T0) and from the margin of one wound per site (thorax, unbandaged limb, bandaged limb) 1 week (T1) and 2 weeks (T2) postoperatively, and at full healing (T3). Thoracic skin samples obtained from three healthy horses were included in the analysis as controls. RESULTS: Anatomic location (thorax vs. limb) significantly influenced bacterial composition of equine skin and healing wounds. Fusobacterium and Actinobacillus were strongly associated with limb wounds during the initial phases of healing. Bandaging had a significant impact on the microbiota during the healing process. The skin microbiota after healing was more similar to samples from controls, demonstrating the resilience and stability of the environment. CONCLUSIONS: Equine skin microbiota is a rich and stable environment that is disturbed by wounding, but returns to its previous stage after full healing. Anatomic location significantly influences bacterial composition of the equine skin during wound healing. Bandaging has a significant impact on the skin microbiota of horses during the healing process. Results of this study provide new insight for a better understanding of the contribution of bacteria to wound healing in horses and may facilitate the future development of therapeutic strategies using commensal bacteria.