Bone fractures are one of the most common reasons for seeking veterinary care. Frequent causes of injuries with bone fractures are car accidents, active play with other animals, fights, gunshot wounds, and in cats, catotrauma (falling from a height).

A bone fracture is a complete or partial violation of bone integrity under a load that exceeds the strength of the injured skeletal area.

Symptoms indicating that an animal has a broken bone:

1. After the injury, an acute pain syndrome is noted; the animal vocalizes (whines).

2. There is a loss of support function - the animal ceases to rely on the limb.

3. Deformity of the free segment of the limb can be observed or unnatural mobility outside the joint can be noted.

4. Swelling at the fracture site may be noted.

As first aid after an injury, you should try to fix the injured limb by applying a fixation bandage. If it is impossible to apply a fixing bandage, it is enough to restrict the animal's movement by closing the animal in a carrier or in an enclosure.

When providing first aid, it is necessary to keep in mind personal safety, as the animal may feel pain and may bite the person providing the aid. For further diagnosis and treatment, it is necessary to visit a clinic.

To diagnose bone fractures, X-ray radiography is mainly used. This method provides information about the type of fracture, the presence of fragments and their displacement.

Photo 0. X-ray of a forearm fracture.

 

Computed tomography is also used to diagnose fractures and plan surgical treatment. CT scan is an indispensable diagnostic method for fractures of the spine, pelvic bones, and skull bones (Photo 1, Photo 2).

Photo 1. CT scan of the dog's skull. Red arrows indicate fractures of the mandible.

Photo 2. CT scan of the pelvic bones.
Red arrows indicate multiple fractures of the pelvis and ilium - sacral dislocation

To choose the right treatment method, it is necessary to classify a specific pearl.

Fractures can be:

1. Traumatic (caused by a load on the bone that exceeds its strength).

2. Pathological - appear when bone strength is lost due to a disease. These include fractures due to:
- Bone tumors (Photo 3, Photo 4).
- Alimentary hyperparathyroidism (Photo 5).
- Disorders of ossification processes (Photo 6).

 

Photo 3. X-ray of the right humerus. Pathologic fracture as a result of tumor lesion is indicated by a white arrow.

Photo 4. X-ray of the bones of the forearm and wrist of the right limb. Pathologic fracture due to tumor lesion is indicated by white arrows.

Photo 5. Radiograph of the pelvic bones and pelvic limbs shows a diffuse decrease in bone density, white arrows indicate fractures of the ilium, femur and tibia due to alimentary hyperparathyroidism.

Photo 6. Fracture of the medial condyle of the humerus in a French bulldog. Arrows indicate the medial condyle.

Connection of the fracture with the environment.

Depending on the communication of the fracture site with the environment, it is divided into closed and open. In a closed fracture, the integrity of the skin is preserved, and it does not communicate with the environment.

In case of an open fracture, the fracture site is exposed to the outside (Photo 7).

Photo 7. Opening of the forearm bone fracture.

By the number of fragments

1. Simple - the fracture line divides the bone into two fragments

- Transverse - crosses the bone at an angle to the longitudinal axis of no more than 30 degrees (A)

- Oblique - the angle of intersection of the longitudinal axis of the bone is more than 30 degrees (B)

- Spiral - a special case of oblique fracture, in which the fracture line curves around the diaphysis (C)

2. Wedge-shaped - a multi-fragment fracture with partial contact between the main fragments after reduction. (D)
3. Fragmented - has one or more completely separated fragments of intermediate size (E)
4. Multiple or segmental fracture - the bone is broken into three or more segments, the fracture line does not meet at a common point.

 

Fractures of the proximal and distal zones of the metaphysis (growth zones) are classified separately; these fractures are typical for young growing animals. Fractures of the proximal and distal parts of long bones are characterized in more detail by the Salter-Harris classification system, which divides fractures of the growth zone into 6 types.

• Type I. Fractures extending through the growth zone
• Type II. A fracture that goes through the growth zone and part of the metaphysis.
• Type III. A fracture that goes through the pineal gland and the growth zone, and is mostly intra-articular.
• Type IV. An intra-articular fracture that goes through the epiphysis, across the growth zone, and through the metaphysis.
• Type V. A fracture that destroys the growth zone, which is not detected radiographically, but manifests itself in a few weeks when growth stops.
• Type VI. The fracture is characterized by partial closure of the growth zone due to damage to a part of the growth zone

 

After examination, radiography and classification of the fracture, the doctor will choose the best method of treatment for a particular fracture.

Treatment methods can be:

• Conservative and surgical.

Conservative methods of treatment include immobilizing bandages, splints, and longitudinal casts. In addition, for some fractures (fractures with alimentary hyperparathyroidism, subperiosteal fractures without displacement of fragments), cage restraint can be used.

Operative methods involve fixation of fragments with the help of various metal structures.

The main criteria for choosing a fixation method.

• Intra-articular fractures always require anatomical repositioning between fragmentary compression to preserve the articular surface and joint function.
• Fractures in the growth zone require anatomical repositioning and fixation without compression to prevent impaired bone growth. It is necessary to remove the implants after fusion.
• For diaphyseal fractures with the possibility of restoring the cortical tube (transverse, oblique, wedge-shaped fractures), absolute stability methods are used after repositioning.

Basic principles of absolute stability:

1. Anatomical repositioning

2. Interfragmentary compression.

3. Early support on the operated limb.

For fractures that cannot be reconstructed, methods that do not require precise repositioning and interfragmentary compression are used. It is sufficient to fixate the proximal and distal bone fragments. It is necessary to preserve the correct angular and axial parameters of the bone (Figure B).

1. Functional repositioning

2. Neutral fixation

3. Early support on the operated limb

The main methods of osteosynthesis.

Intramedullary - used to fix the fracture with pins and rods inserted into the intramedullary canal. The method provides relative stability, resists displacement (axial) and bending loads, but does not resist rotational forces - bone fragments can rotate on the spokes. This method is rarely used in mono mode, but can be used as an additional fixation together with external fixators and plates.

Photo 8. An example of combining intramedullary osteosynthesis with bone osteosynthesis.

Osteosynthesis with screws.

Different screws are used to fix fractures. With the help of screws installed according to the compression principle (compression of bone fragments is ensured), absolute stability can be achieved. This method is extremely rarely used in mono mode, but can be used as an additional fixation or to create interfragmentary compression (Photos 9-10).

Photo 9. The use of a tightening screw for fixation of the iliac sacral joint is indicated by a white arrow.

Photo 10. Use of a Herbert screw for fixation of a fracture of the lateral humerus. The direction is indicated by a white arrow.

 

Osteosynthesis with the help of pins and wire.

The method of fixation of fractures with the use of Zug - gurtung (tensile forces for compression). It is used for fixation of avulsion fractures of the greater trochanter of the femur, tibia tuberosity, ankles, heel bone, and ulnar tuberosity. The method provides interfragmentary compression, which in turn creates favorable conditions for fracture healing. (Photos 11 - 12)

Photo 11. Fixation of the ulnar tuberosity osteotomy using the Zug-gurtung method. Indicated by a white arrow

Photo 12. Fixing a large spit using the Zug-gurtung method. Indicated by a white arrow.

 

Osteosynthesis - a plate is used to fix the fracture, which is fixed to the bone with screws. It can be used both for the treatment of simple transverse fractures, ensuring compliance with the principles of absolute stability (fixation and interfragmentary compression), and for the treatment of complex fractures that cannot be reconstructed, in which case the plate provides conditional stability of bone fragments (Photos 13, 14, 15). Limitations for this type of osteosynthesis are infection in the fracture area, open fractures, and the inability to place 3 screws in each fragment.

. Photo 13. Fixation of mandibular branches fracture by means of bone osteosynthesis

 

. Photo 14. Fixation of the forearm bone fracture by means of bone osteosynthesis.

Photo 15: Fixation of a forearm bone fracture with bone osteosynthesis.

 

Extrafocal osteosynthesis.

For this type of fracture fixation, external fixation devices (EFDs) of various designs (linear and ring) are used (Fig. 1). An external fixation device is a system of spokes or pins that pass through the skin, through soft tissues and bone outside the fracture area, and systems by which they are rigidly fixed to each other from the outside (Photos 16, 17, 18, 19).

Indications for extrafocal osteosynthesis:

1. Fractures that do not require absolute stability

2. Open, gunshot, infection, complex fractures.

3. Fractures in dwarf dogs with minimal distal fragment size (it is impossible to use nailing osteosynthesis).

4. Treatment of nonunion fractures using compression and distraction devices.

5. If necessary, perform a permanent or temporary arthrodesis.

Main types of external fixators:

  

Figure 1. Main types of external fixators.

Photo 16: Fixation of an open compound fracture of the forearm bones using a type 5 ring external fixation apparatus (Ilizarov apparatus)external fixation apparatus type 5 (Ilizarov apparatus)

Photo 17: Fixation of a simple transverse fracture of the forearm bones using an external fixation apparatus type 2.

Photo 18. Fixation of a fracture of the mandibular branches using an external fixation apparatus type 1a.

Photo 19: Fixation of a simple transverse fracture of the forearm bones using an external fixation apparatus type 2.