HORSES with fractures, particularly of the long bones, are infrequently encountered. When a fracture does occur, however, a highly charged situation can arise.
It is very important that any animal with a fracture is dealt with correctly to ensure that the minimum of suffering occurs. A fracture that may be amenable to treatment must be handled with great care to protect the bone and surrounding soft tissues during examination and transportation to a treatment centre.
A fracture that cannot, at present, be treated successfully should be recognised early to allow expedient euthanasia rather than unnecessary transportation.
Coaptation is a mainstay of equine fracture management in the field. It will relieve pain and prevent further injury; however, it is essential that it is correctly applied. A fracture that could be treated may become irreparable if poorly supported.
Classification of fractures
It is important that a fracture is correctly classified to allow the right treatment decisions to be made, particularly if it is to be described to another vet over the telephone.
Incomplete fractures involve only part of the circumference of the bone (only one cortex on radiography) whilst complete fractures involve the entire circumference of the bone (two cortices on radiography) and therefore divide the bone into more than one piece.
Simple fractures divide the bone into two pieces and have only one fracture line whereas comminuted fractures have two or more connecting fracture lines and divide the bone into more than two pieces.
If the skin overlying the fracture is intact then it is described as closed whereas if the skin is broken it is open. An articular fracture crosses the articular surface of a joint.
A clinical examination of the patient should be performed to allow concurrent injuries or complications such as blood loss to be recognised. Several of the larger vessels are found in close association with bone and may be lacerated by sharp fracture fragments. Internal haemorrhage can occur, particularly with pelvic fractures where damage to the iliac vessels may have rapidly fatal consequences.
A horse that has suffered a complete simple or comminuted fracture of a long bone will, in the majority of cases, present with a nonweight-bearing, sudden onset lameness accompanied by signs of distress such as sweating, tachycardia and tachypnoea.
On examination of the affected limb, instability, swelling, crepitus and pain on palpation of the injury site may be recognised. Fractures that are incomplete or involve a bone not directly involved in weight-bearing may result in a less severe lameness and few localising clinical signs.
In such cases manipulation of the limb, including flexion, extension and rotation at all levels, may provoke a response that allows identification of the fracture site. Nerve blocking can be dangerous since a positive block will allow weight bearing on the injury, which could aggravate a fracture with catastrophic results.
Some non-displaced fractures of the diaphysis of the radius and tibia do not show the clinical signs that are normally associated with a fracture to a long bone. Some horses will be only mildly lame and others may show few clinical signs at all.
This type of injury is relatively common as there is little soft tissue to cover the medial aspect of the radius and tibia; therefore, they are particularly vulnerable to trauma.
If a non-displaced radial or tibial fracture is suspected then radiography may be helpful but soon after the initial injury fracture lines may be difficult to recognise. Scintigraphy is useful in identifying these fractures but does require transportation to a hospital facility, which is not practical in every situation.
The main differential diagnoses for a severe lameness in a horse are foot abscess, solar bruise or septic arthritis. It is important to rule out these differential diagnoses (particularly a lesion of the foot) which are more frequently encountered in general equine practice than fractures.
Injured horses may be fractious and difficult to handle and in such cases sedation may be necessary to allow an animal to be properly assessed. The alpha-2 agents xylazine, detomidine and romifidine, with or without butorphanol, can be very useful. A nose twitch may be beneficial in some circumstances but care should be taken to prevent the horse moving violently during tightening, thereby leading to further injury.
Bandaging and splinting
The coaptation applied to a fractured or potentially fractured limb should prevent further bone or soft tissue injury, stabilise the limb allowing ambulation and transportation and prevent further contamination of an open fracture.
The support that is placed on the limb must be sufficient to allow transportation to a facility suitable for assessment and treatment.
Robert Jones Bandage
The Robert Jones Bandage (RJB) is the mainstay for the coaptation of an injured horse limb in a field situation, though in several cases of fracture stabilisation it is insufficient on its own.
A RJB properly applied will require a substantial quantity of materials as well as time and effort. Forafull-limb RJB, 10 rolls of cotton wool and 20 conforming bandages will be necessary.
The limb is wrapped in an even single layer of cotton wool that is compressed by a firm conforming layer. That first layer is followed by successive layers each of a single layer of cotton wool compressed by conforming bandages until the dressing is three times the thickness of the limb that it covers.
The first two layers should be firmly wrapped but by the third layer the conforming bandage should be pulled as hard as possible. The final layer of the dressing should be protected by elastic adhesive tape. When flicked by a finger, the final bandage should sound like a ripe melon and the person who applied it should be sweating.
Splints can greatly improve the support provided by a RJB. Splints may be applied to all aspects of the limb and may be made from wood, PVC or metal, depending on the situation encountered.
Splints should be secured with tightly wrapped non-elastic tape and over the toe; in particular the tape must be thick enough to not wear or tear.
Table 1 details the arrangement of splints necessary for specific regions of the limb. As a rule, two splints should be incorporated into a RJB in two right-angle planes, extending from the hoof to the joint proximal to the fracture in at least one plane.
If the radius or tibia is to be protected, then a padded lateral splint extending above the dressing so that it is in contact with the shoulder or rump should be used. If the ulna, humerus or scapula is affected, then although the fracture itself cannot be supported the horse will find it easier to ambulate if the carpus is braced in extension by a caudal splint.
Commercial splints made from aluminium or plastic are available for the coaptation of the lower limb. They are rapidly and easily applied. The most popular are the Kimsey and Monkey splints, both of which align the dorsal bone cortices.
If on examination a fracture is identified that is definitely untreatable, then it is important that euthanasia is performed as soon as possible and that unnecessary transportation is avoided.
New surgical implants and techniques are constantly being developed to allow the repair of previously irreparable fractures.
At the time of writing, fractures that cannot be treated include open, comminuted fractures with severe tissue damage, complete fractures of the femur, complete fractures of the humerus in an adult horse over 300kg and complete fractures of the tibia in an adult horse over 300kg.
If in doubt, first aid should be administered and a recognised specialist should be contacted for advice.
Bramlage, L. R. (1983) Current concepts of emergency first aid treatment and transportation of equine fracture patients. Comp cont. Educ. Pract. Vet. 5: S564-574.
Walmsley, J. P. (1993) First aid splinting for the fracture patient. Equine Vet. Educ. 5 (1): 61-63.