Marion duPont Scott Equine Medical Center

Therapeutic shoeing for horses is used to affect the palmar angle (PA) of the distal phalanx. These changes may influence the strain on the distal interphalangeal joint collateral ligaments (DIJCLs). This cadaveric study aimed to assess DIJCL strain under varying loads and PA adjustments. Using 26 cadaver forelimbs, eight optical markers were placed on one DIJCL for strain measurement under five different loads (1000-5000 newtons) at a neutral PA, followed by PA increases of 2°, 4°, and 6° and decreases of -2° and -4°. The results indicate that increases in PA corresponded to significantly higher strain in the distal and mid distal portions, while 2° and 4° decreases in PA significantly reduced the strain in the proximal regions of the DIJCLs. Limitations include potential discrepancies between a cadaver and live biomechanics. This study concludes that increased PA increases distal DIJCL strain, while decreased PA decreases proximal strain. Further research is recommended to evaluate the practical implications of these findings in DIJCL injuries in horses.

The recent availability of standing computed tomography (CT) for equine paranasal sinus disease has enhanced diagnosis and enabled more targeted surgery compared to radiography and sinoscopy. To date, there have been no studies which have critically evaluated the benefit of preoperative CT versus radiography and sinoscopy on complications and outcome in horses undergoing sinus trephination. Retrospective study. A total of 229 equids. The medical records of equids (229) presented for sinusitis treated via trephination that had CT, radiography and/or sinoscopy at time of surgery between 2009 and 2022 were reviewed. Outcome and complications were evaluated for six different pre- and intraoperative imaging modalities. The six groups did not differ in demographics or disease category, though equids with less weight (p = .0179) and shorter disease duration (p = .0075) were more likely to have radiography and sinoscopy based surgical planning. Short-term postoperative complications occurred in 30.1% and were higher in groups using preoperative CT imaging (p = .01), with hemorrhage being the most common surgical complication. Following initial trephination surgery, 57.0% (127/223) of cases resolved and there was no difference between the imaging groups. Final resolution after follow-up medical or surgical treatment increased to 94.6% (211/223) and was not different between the imaging groups or between primary or secondary sinusitis. Additional nasal fenestrations to improve sinonasal drainage, maxillary septal bulla fenestrations and trephinations to treat nasal conchal bullae were made in the CT groups. CT provided additional diagnostic information and enabled different surgical approaches but did not improve resolution in this study population.

Although the external conformation of wild horse hooves has been proposed as an ideal model for domesticated modern horses, histological signs of laminitis have been reported among them. With the hypothesis that the lamellar tissue of horses of Iberian origin raised in semi-feral is healthier than those raised in an intensive management system (stall confinement and high-calorie diet intake), the objective was to compare their lamellar tissues. Lamellar tissue samples were taken from the forelimb hoof of eight domesticated Mangalarga Marchador (MM) horses and from six semi-feral Marajoara (MJ) and Puruca (MP) horses. Primary epidermal lamella (PEL) and secondary epidermal lamella (SEL) were measured (length and width) in several regions, and their shapes were morphologically classified into different types. Breed groups were compared using analysis of variance, followed by Tukey or Dunn tests (P<0.05). Early signs of laminitis such as abnormal keratinization of the abaxial primary dermal lamella, tapered tips of the axial PELs, pointed tips of the SEL, nuclei condensation, and abnormal spatial orientation of the secondary epidermal basal cells (SELBC), were seen only in MM horses. MP horses had a greater interface of epidermis/dermis contact than MJ horses and more rounded nuclei in the round SELBC than MM horses. In agreement with the study hypothesis, semi-feral MJ and MP horses' lamellae were classified as healthier than MM horses, which showed early signs of endocrinopathic laminitis.

SummaryThis case report describes the treatment and outcome of a 3.5‐month‐old lame foal, with a history of pneumonia associated withRhodococcus equi. Clinical examination identified osteomyelitis of the scapulohumeral joint. The unusual location of theRhodococcus equiosteomyelitis unresponsive to prevention and adequate treatment led to euthanasia of the patient. Post‐mortem findings confirmed bronchopneumonia due toRhodococcus equias well as the osteomyelitis of the scapulohumeral joint. This case highlights thatRhodococcus equishould be considered as a pathogen in extrapulmonary locations such as septic arthritis and osteomyelitis in foals with history of bronchopneumonia. Early and aggressive treatment should be considered.

SummaryA 27‐year‐old Thoroughbred mare presented for computed tomography (CT) of the head following a 3‐month history of facial swelling at the infraorbital foramen, unilateral self‐mutilation and head‐shaking. StandingCTimaging showed soft tissue attenuation surrounding the infraorbital canal, with extensive bony lysis of the canal and maxillary bone at the infraorbital foramen. The mare was subjected to euthanasia, and post‐mortem examination revealed a proliferative tan soft tissue mass overlying the infraorbital nerve. A histopathological diagnosis of pleomorphic sarcoma with giant cells was made. Immunohistochemical analysis failed to fully elucidate the mesenchymal cell of origin of the sarcoma. Pleomorphic sarcoma with giant cells involving the infraorbital canal of the horse has not been previously described. This case highlights chronic subtle behavioural changes attributable to this neoplasm prior to the development of clinical signs and the utility of advanced imaging in the diagnosis.

Determining the need for surgery for a horse with colic is often an emergency. Because making a specific diagnosis frequently is not possible, clinical signs are the most useful indications to categorize the disease process. The most helpful signs and clinical values include pain severity, heart rate, peritoneal fluid protein and cell count, peritoneal lactate, rectal examination, auscultation of intestinal movement, and degree of shock. Lack of response to analgesics and unrelenting pain by itself are reasons to explore the abdomen surgically. When there is uncertainty about the need for surgery, surgery is usually necessary.

Surgical colic in the foal can be difficult to distinguish from medical colic but requires prompt intervention for optimal outcomes. Small intestinal strangulating obstruction is the most common surgical finding in neonates, while findings in older foals more closely mimic those found in adult horses. Specific techniques for repairing gastrointestinal lesions that are more common in foals than in adults (e.g., gastric outflow obstruction) are discussed. Although postoperative survival has improved, prognosis for surgical colic in foals remains poorer than in adults, partly owing to the presence of concurrent systemic diseases and partly to the predisposition of the foal to form intra-abdominal adhesions.

To report clinical findings and outcomes for 55 dogs with supraspinatus tendinopathy (ST) treated with adipose-derived progenitor cells and platelet-rich plasma (ADPC-PRP) therapy. Medical records of client-owned dogs diagnosed with ST that were treated with ADPC-PRP combination therapy were reviewed from 2006 to 2013. Data collected included signalment, medical history, limb involvement, prior treatments, physical and orthopedic examination, objective temporospatial gait analysis findings, diagnostic imaging results (radiography, magnetic resonance imaging, musculoskeletal ultrasonography), arthroscopy findings, and outcome. Following ultrasound-guided injection of ADPC-PRP, objective gait analysis was available on 25 of the 55 dogs at 90 days post ADPC-PRP therapy. Following treatment, a significant increase in total pressure index percentage (TPI%) was noted in the injured (treated) forelimb at 90 days post treatment (p = 0.036). At 90 days following treatment, 88% of cases had no significant difference in TPI% of the injured limb to the contralateral limb. The remaining 12% of cases had significantly improved (p = 0.036). Bilateral shoulder diagnostic musculoskeletal ultrasound revealed a significant reduction in tendon size (CSA) in the treated tendon at 90 days following treatment when compared to the initial CSA (p = 0.005). All cases showed significant improvement in fiber pattern of the affected supraspinatus tendon by the ultrasound shoulder pathology rating scale. These findings suggest that ADPC-PRP therapy should be considered for dogs with ST.

&lt;p&gt;&lt;strong&gt;Objective:&lt;/strong&gt; To report clinical findings and treatments for dogs with supraspinatus tendinopathy (ST).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; ST is a term used to describe tears, calcifying tendinopathy, tendinosis and/or injuries in and around the tendon of the supraspinatus muscle, and is a cause of forelimb lameness, especially in sporting and performance dogs.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Evidentiary value: &lt;/strong&gt;This is a retrospective study of 327 dogs diagnosed with ST.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Medical records (2006 to 2013) were reviewed for history, signalment, prior treatments, physical examination findings, diagnostic imaging and arthroscopic findings, concurrent shoulder and elbow pathologies, and treatments performed.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Dogs aged 4 months to 14 years (average 6.5 years; median 6 years) were diagnosed with ST. Performance and sporting dogs were 39.4% of the population, with 58.1% of them being agility dogs. Pain was elicited on palpation of the supraspinatus tendon in 49.3% of dogs. Shoulder radiographs in 283 dogs showed mineralisation in 13% of cases. MRI of the shoulder was performed in 31 cases and revealed findings indicative of ST, including hyperintensity of signal on T1 weighted image (or “spin-lattice”) and Short T1 Inversion Recovery (STIR) sequences of the supraspinatus tendon at its insertion on the greater tubercle and mineralisation of the supraspinatus tendon. Common ultrasonographic findings included increased tendon size (76%), irregular fibre pattern (74%), and non-homogeneous echogenicity (92.5%). The most common findings on shoulder arthroscopy were supraspinatus bulge (82.2%) and subscapularis pathology (62.4%). Elbow pathology was recorded in 54.5% of dogs. Treatment outcomes showed 74.6% of dogs failed to respond to non-steroidal anti-inflammatory drugs (NSAID) and 40.8% failed to respond to rehabilitation. &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; These findings suggest concurrent shoulder and/or elbow pathology is not uncommon in dogs with ST. Further, ST often fails to respond to NSAID therapy and rehabilitation therapy. &lt;/p&gt;&lt;strong&gt;Application:&lt;/strong&gt; Other treatments such as regenerative medicine should be considered. Future studies are still needed to assess the use and efficacy of regenerative medicine for ST.

Tendon bioreactors combine cells, scaffold, and mechanical stimulation to drive tissue neogenesis ex vivo. Faithful recapitulation of the native tendon microenvironment is essential for stimulating graft maturation or modeling tendon biology. As the mediator between cells and mechanical stimulation, the properties of a scaffold constitute perhaps the most essential elements in a bioreactor system. One method of achieving native scaffold properties is to process tendon allograft in a manner that removes cells without modifying structure and function: "decellularization." This chapter describes (1) production of tendon scaffolds derived from native extracellular matrix, (2) preparation of cell-laden scaffolds prior to bioreactor culture, and (3) tissue processing post-harvest for gene expression analysis. These methods may be applied for a variety of applications including graft production, cell priming prior to transplantation and basic investigations of tendon cell biology.