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EQUINE VETERINARY EDUCATION / AE / SEPTEMBER 2017
Case Report
Spontaneous hoof capsule loss following lacerations of the equine distal limb
P. Ruzickova*, P. Trencart and S. Laverty D
epartement de Sciences Cliniques, Facult Qu Keywords: horse; hoof loss; laceration
Summary In this article, 3 cases of an infrequent complication of lower limb trauma that presented as a cellulitis and deteriorating comfort a few days after lower limb laceration are described. All 3 horses sloughed the hoof capsule 10 days after initial trauma to that particular limb. Development of subsequent cellulitis/lymphangitis contributed to deterioration of distal limb perfusion. The exact pathophysiological mechanisms remain unknown but clinicians should be aware of this unusual but major complication following limb trauma.
Introduction
The equine hoof capsule, encompassing the wall, sole, heels and frog, is an epidermal tissue attached to the distal phalanx by a highly organised intermeshed network of primary and secondary lamellae. The lamellar blood supply arises from the lateral and medial digital arteries (K€
onig and
Liebich 2014) and they also furnish branches to the hoof cartilages, coronary band, digital cushion and end in the terminal arch and solar surface vessels. Partial traumatic avulsions of the hoof wall are common
and if synovial structures are not involved usually have a good prognosis for regrowth of a functional hoof (Janicek et al. 2005). Complete loss of the hoof capsule due to trauma, on the other hand, has a poor prognosis for return to normal function. There are few case reports of complete traumatic hoof capsule loss in the veterinary literature in the last 50 years and all involve single cases (Jackson 1969; Stanek and Brkic 1981; de Gresti et al. 2008). Although prolonged inadequate perfusion of the distal
limb has briefly been mentioned as a cause of hoof capsule slough (Floyd and Mansmann 2007), we were unable to find any detailed descriptions addressing this condition in the English veterinary literature. The case series reported herein is novel as it provides the first detailed clinical description of 3 horses that sloughed the hoof capsule subsequent to trauma of that particular limb.
Case selection
Medical records of all horses examined at our institution between 2000 and 2013 were searched. Horses that suffered from spontaneous hoof capsule loss following an ipsilateral distal limb laceration were included in the study. Horses with laminitis or traumatic avulsion of the hoof capsule were excluded. A total of 3 horses met the inclusion criteria.
© 2016 EVJ Ltd
Case 1 A 2-year-old Friesian filly was referred to the Veterinary Teaching Hospital at the University of Montreal having fallen into a deep ditch where she remained trapped, despite struggling to free herself, until rescued. The owner and referring veterinarian did not observe any haemorrhage indicative of vessel trauma. On presentation, a 3/5 lameness (AAEP lameness scale [Anon 1991]) was present in the left hindlimb. Skin lacerations and exposed bone were present at the dorsomedial aspect of the metatarsus and lateral aspect of the fetlock of the left hindlimb (Fig 1a). Clinical examination of the wound by digital palpation while wearing sterile gloves and gentle probing with a sterile long thin metal probe revealed a communication with the metatarsophalangeal joint. A simple fracture of the distal MtII was diagnosed on radiographic examination. Arthrocentesis of the metatarsophalangeal joint was performed. The synovial fluid total protein was 46 g/l and the WBC 5.83 9 109/l with 94% neutrophils. Escherichia coli was cultured from the synovial fluid and was sensitive to enrofloxacin, chloramphenicol and amikacin. The wounds were debrided, the metatarsophalangeal joint lavaged arthroscopically and wounds sutured under general anaesthesia. Amikacin (Amyglide-V)1 (500 mg) was injected intra-articularly at the end of the surgical procedure. The mare developed an expanding cellulitis in the left
hindlimb on Day 6 post-operatively. Broad spectrum intravenous (i.v.) antibiotics (penicillin [Penicillin G Sodium]2 22,000 iu/kg bwt i.v. q. 6 h, gentamicin (Gentocin)3 (6.6 mg/kg bwt i.v. q. 24 h) were administered for the first 12 days but therapy was changed to oral enrofloxacin4 (7.5 mg/kg bwt per os q. 24 h) based on sensitivity testing. Enrofloxacin4 was administered for 6 days. Regional limb perfusions (1 g amikacin)1 were also performed in the saphenous vein on Days 3, 5, 7 and 9 post-operatively. No problems were identified in the perfused vein apart from minor swelling. Phenylbutazone5 (2.2 mg/kg bwt per os q. 24 h) was administered during the entire hospitalisation period (23 days).
Throughout hospitalisation the mare exhibited only minor
discomfort on the affected limb. Unexpectedly, on the 10th day after admission, the hoof capsule sloughed. Necrotic dermal lamellae and the distal phalanx were visible (Fig 1b).
Standing surgical debridement of the necrotic lamellar
tissue and daily bandage changes were performed. The mare developed an episode of mild colic that resolved with medical therapy (water and mineral oil administered by
ede M edecine V erinaire, Universit et
ebec, Canada. *Corresponding author email:
pavlina.ruzickova@
umontreal.ca
e de Montr eal, St Hyacinthe,
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