Page 440 - WSAVA2018
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 25-28 September, 2018 | Singapore
A. Piras1
1Specialist in Veterinary Surgery, Ravenna, Italy
Comminuted Fractures New Strategies that Simplify Treatment of this Challenging Fractures
Alessandro Piras
DVM - Specialist in Veterinary Surgery
Comminuted fractures can be especially challenging
due to the complexity of the fracture fragments and concomitant soft tissue injury. Careful consideration should be given to decision-making prior to onset of fracture repair. Factors that should be considered include mechanical, biological and postoperative compliance. Complex fractures that are treated with a mechanically sound repair often leave the surgeon pondering what could have possibly gone wrong when a “perfect”
repair fails. Often times, the answer lies in the neglect
of the biological or postoperative compliance factors. Neurologic function should always be assessed because complex fractures are often associated with high-
energy trauma that also can injure the brachial plexus
or peripheral nerves of the forelimb. This lecture will focus on presentation of clinical cases involving complex fractures of the forelimb and hindlimb, with an emphasis on the decision-making process. A variety of fracture repair techniques will be discussed including interlocking nails, plate-rod construct and linear external fixators.
Minimally-invasive surgical approaches reduce pain and minimize trauma to the soft tissues. Biological factors important for fracture healing are preserved, enhancing the body’s ability for indirect bone healing. The technique can be used with all fracture types, but is particularly useful for stabilization of comminuted fractures. This type of bone healing is also referred
to as secondary bone healing, spontaneous bone healing and callus healing. Stabilization of fractures using the principles of biologic fracture management is performed with the same type of implant systems used with traditional fracture repair, including externally and internally applied devices.
Fracture Management
Comminuted fractures of the extremities can be challenging. It is always a race between a fracture healing and an implant failing. Steps can be taken to tip the scale in the direction of early fracture healing. These steps include:
1. Minimally invasive surgical approach
2. Preservation of soft tissue attachments to bone fragments
3. Use of cancellous bone grafts
4. Rigid method of fracture stabilization
5. Early return to function
It is always important to obtain an accurate history prior to stabilizing fractures. A complete physical exam and appropriate diagnostic tests should be performed. Pathologic fractures are more likely to be seen in
the geriatric dog and cat and should be identified preoperatively to ensure proper client education and communication
Indirect Bone Healing
Biological fracture management utilizes indirect fracture reduction to preserve the soft tissue envelope at the expense of anatomic reduction. Indirect bone healing occurs as a result. Indirect bone healing consists of three elements: first the formation of granulation tissue at the fracture site, second is fracture gap widening due to resorption of the bone ends and third is the new bone formation involving generation of a bone callus. Less disruption of the vascular supply to bone fragments is achieved through minimal handling of the fragments, promoting early callus formation.2,3,6,7 Indirect bone healing is first associated with the formation of fibrous connective tissue and cartilage callus between the fragments.4 Indirect bone healing occurs due to instability at the fracture
site and is partially regulated by fragment gap strain.4 Interfragmentary strain is a ratio of change in the gap width to the total width prior to physiological loading.1,5 A study of the “interfragmentary strain hypothesis” using ovine osteotomy models demonstrated that the initial stages of indirect bone healing occur earlier and more extensively between gaps with lower shear strain.1 Management
of a non-reducible diaphyseal fracture with an implant system that does not utilize anatomical reconstruction and creation of subsequent small fracture gaps avoids high interfragmentary strain, favouring bone healing.
Implant Systems
External and internal implant systems can be used
to achieve bone healing using biological fracture management. Examples of external devices when used in an appropriate manner include casts, splints, linear external fixators and circular fixators. Internal devices commonly used for this application include the plate- rod system, interlocking nail and bone plates. Other implant systems can also be used for biologic fracture management as long as the soft tissue envelope is preserved at the fracture site. Whatever implant system is used, its application must be possible with minimal or no handling of the comminuted fracture fragments.
External Fixator
External fixators provide rigid stabilization and can be

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