Case Description—A 4-month-old Standardbred colt was examined because of a fractured right calcaneus of 8 days' duration with increased distraction of the fracture fragment evident on sequential radiographs.
Clinical Findings—The foal was severely lame with diffuse periarticular tarsal swelling. Radiographically, a complete, displaced long oblique fracture of the right calcaneal body was evident. Because the fracture gap was increasing with time and lameness remained severe, despite medical management, surgical repair was recommended.
Treatment and Outcome—The foal was anesthetized, and minimally invasive fracture reduction and internal fixation were achieved by use of two 4.5-mm cortical screws placed in lag fashion via stab incisions over the lateral aspect of the calcaneus. External coaptation with a Robert-Jones bandage only was used after surgery. The foal recovered well and the fracture healed appropriately, but at 8 weeks following surgery, tenosynovitis of the tarsal sheath had developed. This was attributed to the tip of the distal screw encroaching on the sheath. The screw was removed under anesthesia and the tarsal sheath drained. The tenosynovitis resolved with rest and bandaging. Fourteen months after surgery, the colt was free of lameness.
Clinical Relevance—Findings suggested that a minimally invasive internal fixation technique for treatment of a calcaneus fracture in horses may be successful and may be associated with decreased morbidity, compared with the use of open reduction and plate fixation.
To describe the antimicrobial susceptibility patterns of the most commonly isolated bacteria cultured from synovial fluid samples from horses with suspected septic synovitis treated at an equine referral hospital between May 1, 2008, and September 24, 2017.
131 synovial fluid samples from 108 client-owned horses.
A retrospective medical record search was conducted to identify horses with suspected septic synovitis and results of synovial fluid bacterial culture and antimicrobial susceptibility testing. Data collected included signalment, known or suspected origin of synovial contamination, synovial structures affected, antimicrobial treatment, and results of synovial fluid cytologic evaluation and bacterial culture and susceptibility testing. Horses were grouped as adults (≥ 6 months old) or foals (< 6 months old).
Results of bacterial culture were positive for 34 of 70 (49%) and 18 of 61 (30%) samples from 68 adult horses and 40 foals, respectively. Gram-positive bacteria were more common in adult horses, whereas gram-negative bacteria were more common in foals. No multidrug-resistant microorganisms were identified. For adult horses, 92% (23/25) of gram-positive isolates tested with penicillin and gentamicin were susceptible to the combination. For foals, 94% (15/16) of isolates tested with penicillin, gentamicin, or both had susceptibility to 1 or both antimicrobials.
CONCLUSIONS AND CLINICAL RELEVANCE
Periodic review of bacterial profiles and antimicrobial susceptibility in horses with septic synovitis can help to detect early changes in bacterial pressure and antimicrobial resistance. Findings suggested that in the geographic area we serve, a combination of penicillin and gentamicin would be an effective empirical antimicrobial treatment for most horses with septic synovitis while results of bacterial culture and susceptibility are pending.
CASE DESCRIPTION 4 horses were examined because of signs of chronic hind limb lameness.
CLINICAL FINDINGS 3 horses had a history of lameness for > 6 months; specific duration was unknown for 1 horse. On initial evaluation, grade 3 to 4 (on a scale from 1 to 5) hind limb lameness was present in all 4 horses. Radiography of the stifle joint of the affected limb revealed medial femoral condyle subchondral lucencies or subchondral cystic lesions (SCLs) in all 4 horses, medial femorotibial osteoarthritis in 3 horses, and medial tibial condyle SCLs in 3 horses.
TREATMENT AND OUTCOME 2 horses were treated medically (stall rest and oral NSAID administration), and 2 horses were treated surgically by means of medial femoral transcondylar lag screw placement through the medial femoral condyle SCLs. The 2 horses treated medically did not improve and were euthanized. Necropsy confirmed the presence of medial femoral condyle and medial tibial condyle SCLs. Surgical treatment did not resolve the lameness in 1 horse with SCLs in the medial tibial condyle and medial femoral condyle, and euthanasia was performed 150 days after surgery. In the second horse, a medial tibial condyle SCL was evident on radiographs obtained 3 months after surgery; however, this was not addressed surgically, and signs of lameness resolved 11 months after surgery.
CLINICAL RELEVANCE Results of this small case series suggested that SCLs in the medial tibial condyle can occur in association with SCLs of the medial femoral condyle, with a poor prognosis for return to athletic function in affected horses. Further investigation is indicated.
Case Description—2 horses were examined for chronic nasal discharge secondary to unilateral guttural pouch mycosis.
Clinical Findings—Initial endoscopic examination of both horses confirmed the presence of a fungal plaque on the dorsomedial aspect of the medial compartment of the guttural pouch (auditory tube diverticulum) involving the internal carotid artery (ICA). No signs of hemorrhage or neurologic deficits were present at admission.
Treatment and Outcome—Transarterial stainless steel coil embolization of the affected ICA was performed under general anesthesia, with fluoroscopic guidance. During treatment, an aberrant branch of the ICA, or a proposed bifid ICA, that anastomosed with the caudal cerebellar artery was identified. Occlusion of the distal (noncardiac) side of the aberrant branch was performed in both horses because of potential mycotic involvement at that level. Following treatment, resolution of the mycotic infection was observed in both horses; however, 1 horse developed neurologic signs compatible with unilateral caudal cerebellar artery ischemia on recovery from anesthesia; these signs resolved over the following 2 months.
Clinical Relevance—Findings highlighted variability of the anatomy of the ICA in 2 horses that was identified during treatment for guttural pouch mycosis and identified caudal cerebellar artery infarction as a potential complication of treatment. Because of the size and pathway of both arterial branches, we suggest that the term bifurcation of the ICA is more appropriate than aberrant branching, as has been previously described in the literature. The information in this report may be of value to clinicians performing procedures involving the vasculature of the head and neck in horses.