Types of Fractures

• A fracture is a disruption of the continuing of a bone and the exact nature may be safely determined only by radiography.

• Palpation may be informative but it may also cause pain and may damage the haematoma and fibrin bridge which is important in giving the fragment a start toward healing. An accurate clinical history may support diagnosis of the fractures.

• Radiography of fracture is used to determine the:

• Types of fracture

• Damage to surrounding soft tissues and joints.

• The accuracy of reduction, to determined the progress of healing.

• To correctly determine the exact relationship of the fracture fragment.

• Radiographs must be made in at least two planes Informative radiographs must be made in at least to include one adjacent joint and preferably both the proximal and distal joints to permit evaluation for possible rotation of the fracture fragments or other types of misalignment.

• An animal suspected of having a fracture must be handled with care and consideration. A preliminary survey film made closed to the severity of fracture.

• For more positive definition a second set of radiograph can be made after the animal has been recovered from shock and prior to surgical immobilization of the fragments. Restrain for proper positioning may require for used of anesthesia to overcome pain and muscular spasm.

• The following items on the radiograph must be noted carefully, as they influence the choice of immobilization device and helping estimating the rate of healing of fracture:-

• Type and extent of the fracture.

• Alignment of fragments.

• Degree of end to end apposition of fragments.

• Extent of shorting of the bone due to overriding of fragments.

• Torsion or twisting of the fragments.

• Soft tissues between fracture fragments.

• Following reduction of the fracture, additional radiographic examinations are essential to determine the degree of reduction and to determine the rate of healing. It is not possible to specify the exact interval for the follow up radiographic examinations because the rate of healing of fractures depends on several factors:-

• The type of original fracture.

• The bone involved.

• The age of the animal.

• Nutritional level of the animal.

• Degree of reduction.

• The amount of motion at the fracture site.

• The presence of infection.

• The kind of immobilization device utilized.

• Two or three weeks might be considered an average length of time between radiographic examination to determine the rate of fracture healing.

• Radiography of fractures

• Fractures are readily classified into several categories on the basis of their objective radiographic appearance. Any of several types of fractures may be compound.

• Description of fractures as compound implies only a complication of a primary fractures by the presence of an external wound rather than a separate fracture type.

• The finding of a small amount of air either subcutaneously or within the fascial planes indicating that the skin is broken and the fracture is an open or compound.

• Simple fractures

• A simple fracture that is non comminuted appears on the radiograph as a radiolucent line or zone in an otherwise normal appearing bone. The bones on either side of the radiolucent zone are considered fragments; the fracture line may be oblique, spiral and transverse (skin intact) (Figure 1) .

• Comminuted fractures

• Beside the major fracture line comminuted fractures have one or more similar secondary fracture line that create a number of additional  fragments. The secondary fractures may have occurred at the time of original injury or later owing to stress (gun shot wound)   (Figures  2, 3, 4, 5) .

• Multiple fractures

• When two or more complete fracture lines involve the shaft of a single bone. Multiple fracture are differentiated from comminuted fracture by the greater size of the segment of bone between the two fracture line. The difference between comminuted and multiple fractures is not always great (Figure 6) .

• Avulsion fractures 

• These are two types:

• A fragment of bone may be avulsed by tearing of a ligamentous, tendinous or muscular attachment to bone. The freed bone fragment is deposited in the neighboring soft tissues, leaving a roughened irregular defect on the adjacent bone indicating the origin of the fragment. The avulsion of the extensor process of the 3^rd phalanx of the horse is one of the best example of such fracture.

• The second type of avulsion fracture occur in young  animals prior to skeletal maturation and consists of avulsion of developing  secondary center of ossification e.g. shift of the ossification center for the tibial crest and proximal tibial epiphysis.

• Chip fractures

• Chip fractures are similar in many ways to avulsion fractures. however chip fracture commonly originate from the tip of an articular surface. The fragment may separate from its point of origin or may remain closely fit into the detect created by the carpal bones and the anterior aspect of the proximal lip of the first phalanx are often involved with chip fractures

• Saucer fractures

• Fractures producing a bone fragment with a saucer shape are referred to as saucer fractures such a fracture commonly originates from the midshaft of long bones such as the equine metacarpal / tarsal bones following direct trauma. Soft tissues injury is easily noted on the radiograph and the fragment may be separated from the shaft of the bone. The fragment is composed primarily of cortical bone and the possibility of sequestrum through loss of its blood supply is great.

• Fracture of the margin of 3^rd phalanx of a horse may be saucer fractures and oblique view may be required to identify the fracture line if separation of the fragment is not great.

• Incomplete fractures

• Incomplete fractures in which the fractures line does not extend entirely though the bone are rare in animals, probably because of the lack of protection given to the injured bone following the initial injury.

• If a fracture were incomplete the animal possibly would attempt to use the limb and complete the fracture. If fracture will remain incomplete there would be little or no angular deformity and little or no displacement and healing could occur without knowledge of the fracture such a fracture would be difficult to identify radiographically until resolution of bone had occurred at the fracture site.

• Greenstick fractures

• Greenstick fractures are not common animals, occurring almost solely in younger animals with more resilient bone due to incomplete calcification.

• Failure to recognize this type of fracture may be due to the animal not limping severely or long enough to be brought for treatment. Radiographically a radiolucent fracture line extends through one cortex and the opposite cortex remains intact and the bone is partially bent and partially broken.

• Impacted fractures

• Impacted fractures are rare when found they present as a complete or incomplete fractures with secondary impaction of the fragment with radiopaque fracture lines because of the impaction.