Fracture description and radiographic assessment of healing

• What are the different types of fracture classification?

  Articular vs non-articular

  Diaphyseal, metaphyseal and epiphyseal.

  Description of the fracture transverse/oblique or of a major fragment e.g. butterfly.

  Physeal fractures

  Closed vs open

  Simple vs comminuted

  Avulsion fractures

  Cause e.g. traumatic vs pathological
• Articular vs non-articular fractures

  Simply put this means that the fracture either involves a joint surface (articular) or does not.

  This distinction is important considerations in how the fracture is managed and the complications that might arise.

  Articular fracture e.g. fracture to the femoral head, these fractures always end up with an arthritic joint.
• Diaphyseal, metaphyseal and epiphyseal fractures

  This is a classification of the anatomical location of the fracture.

  Diaphysis is the shaft of the bone - the correct is thick and bone is strong.

  Metaphysis is the transition from the physis or growth plate to the diaphysis - the cortices are thinner, there is much cancellous bone and reduced volume to the medullary cavity. The bone is generally softer and the implants don’t grasp as well.

  Epiphysis is the end of the bone which is covered in articular cartilage making up the joint.
• What are physeal fractures?

  This is a classification for those fractures through the growth plate or physis. The classification is called the Salter Harris system
• What are the types in the Salter Harris system?

  Type 1 - just involving the physis.

  Type 2 - physeak fracture and including a small amount of the metaphysis.

  Type 3 - physeal fracture with a small portion of the epiphysis.

  Type 4 - fracture through the physis and includes a section of the metaphysis and epiphysis.

  Type 5 non-displateced compression of the physis on one side. This can give rise to premature closure of the growth and angular limb deformities.
• Physeal fracture of the tibial plateau

  This is a relatively common fracture seen in Border and West Highland white terriers. If untreated the tibial plateau remains at a greater angle and puts extra strain on the cranial cruciate ligament. It is a combination of a physeal fracture to the tibial plateau and tibial tuberosity.

  
• Fracture of the capital physis

  This is a typical fracture that occurs in the young male cat, particularly the Burmese. Repair is within 2 or 3 k wires and weight bearing compresses the fracture.

  Healing can be poor and either the femoral head or neck ostectomy or total hip replacement might be required to manage this condition.
• Distal femoral physeal fracture

  This is a common fracture, this case is minimally displaced but some will cause the diaphysis to lie within the medial quadriceps. Repair is by cross pins.
• What are the types of open fracture?

  Type I - small wound (<1cm), little contamination. Treat as a closed fracture.

  Type II - extensive wound (>1cm) communicating with the fracture.

  • All comminuted fractures irrespective of wound size are classified as type II.

  Type III - very extensive soft tissue damage and fractured bones are seen protruding through the skin.
• Simple vs comminuted fractures

  Simple fracture consist of two fragment.

  Comminuted fracture consist of at least 3 fragments.

  Segmental fracture is the comminuted fracture where the fractures do not interact.

  The fixation applied is determined by the degree of comminution.

  
• Avulsion fracture

  This is a description of a particular fracture type when a distractive force results in the fracture and also tends to bring about a loss of reduction.

  Reduction is when the fracture bone is reconstructed.

  Reduction is followed by fixation which aims to maintain the reduction to allow healing.
• What are traumatic fractures?

  A traumatic fracture is associated with a trauma.

  The most common trauma is RTAs but includes falls from heights, particularly in young puppies dropped by their owner and gunshot injuries. Lateral condylar fractures in french bulldogs due to the weakness there.
• What are pathological fractures?

  Pathological fractures originate from a weakening of the bone by a pathological process.

  Examples of this are neoplasia when very minor trauma will result in a limb fracture (always be aware of this in the older dog) or Humeral intercondylar fissure or slipped capital physis in certain feline breeds or folding fractures in nutritional hyperparathyroidism (poorly mineralised skeleton that is prone to fractures).
• Bone healing - radiography

  Bone healing can be assessed and monitored radiographically.

  This is an important means of determining how well the healing process is doing. This is secondary to the clinical improvement in the use of the limb shown by the patient.

  Radiographic changes at the fracture site show a standard progression, the changes seen are altered by whether the healing is primary or secondary.
• What is primary bone healing?

  Primary is when there is bone to bone healing. This required intimate contact of the bone ends, preferably under compression. It requires application of a bone plate and extensive dissection and manipulation of soft tissues. It is generally accompanied by early use of the limb.
• What is secondary bone healing?

  Secondary is where there is intervening callus information, this does not required accurate reduction of the fracture e.g. application of an external fixator without manipulation of the fracture itself or adopting a look but do not touch approach (LBDT) or minimally invasive plate osteosynthesis (MIPO) when a plate is placed through subcutaneous tunnels.