Fractures In Pets
Written by Shula Berg BVSc CertAVP(GSAS) GPAdvCert(SASTS) MRCVS
Clinically reviewed by Elizabeth McLennan-Green BVM&S CertAVP(SAM) MRCVS
Table of Contents
- Overview
- Diagnosis
- Treatment
- Complications
- Outlook
What is a fracture?
A fracture means a break in a bone. This can be a major bone, such as the femur (thigh bone), to a tiny bone in the foot. Most fractures happen suddenly, due to a traumatic incident such as being hit by a car or falling from a height. Some fractures, however, can be caused by relatively minor force, especially in young animals whose bones are softer. Sometimes an underlying disease process can cause the bones to become weaker, and a resulting break is known as a pathological fracture.
Fractures of the main bones will cause non-weight-bearing lameness, and the leg may be obviously at a strange angle. Fractures of smaller bones may cause intermittent, or milder lameness.
How are fractures diagnosed?
Although examination may be very suggestive, fractures can only be diagnosed using radiographs (x-rays). At least two images are taken at 90° to each other to get a clear view of the configuration of the fracture. Sometimes the un-injured limb is also imaged for comparison, or to measure what size implants are needed.
If the fracture happened during a major trauma, such as a car accident, we must be sure there are no other injuries, as these can be more serious than a broken leg. In these patients, imaging may include the chest, abdomen or pelvis. Additional tests, such as blood tests, may also be needed to assess for damage.
How are fractures treated?
The most important factor for successful bone healing is immobilisation of the fragments. This allows delicate new cells to form, bridging the gap between the broken bones and, eventually, remodelling into strong bone. If the fragment ends are moving in relation to each other, these cells can’t successfully connect the two ends, and healing will not occur.
Fractures are described as simple or complex. A simple fracture is a “clean break”, and re-aligning the fracture ends will allow the limb to support weight. A complex fracture often involves multiple fragments of bone. These are harder to repair, and will require implants to carry more of the weight.
Broadly speaking, there are two ways to treat fractures; external coaptation or surgical stabilisation. One or both of these techniques may be used in an individual. Managing fractures can be very involved, and surgery can be technically challenging. Referral to a specialist surgeon, or a vet with a strong interest in orthopaedics, may be advised.
External coaptation
This means immobilising the fracture from the outside, using a dressing or cast. It provides less controlled immobilisation compared to surgery, so is only suitable for certain types of fractures. It is often used in very young animals who heal quickly.
The main advantage of external stabilisation is the avoidance of surgery. Depending on the case it can be, but is not always, cheaper. Complications can occur with bandaging, especially rubs and pressure sores. It is essential that the dressing is kept clean and dry, replaced at regular intervals, and monitored for signs of slipping. Some animals will require sedation for every dressing change to ensure they don’t wriggle.
Surgical stabilisation
Surgical stabilisation uses metal implants to hold the fractured bone stable. This can be internal (usually plates and screws) or external (a frame known as an “ex-fix”), along with a combination of pins and/or wires. Some fracture types are only suited to one of these options, while for others the surgeon will decide the best method.
Internal fixation often remains inside the patient for life, even after bone has healed. Occasionally, however, these fixings will need removing.
External fixation will need to be taken off, a process which may be done in stages. Depending on the location and type of fracture, surgery will ideally be performed within five days of injury.
What complications can occur with fractures?
As with any major surgery, complications can occur. The following complications can occur after fracture repair:
Infection
Superficial infections around the wound are easily treated, and can usually be prevented by keeping the buster collar on your pet. Deep infections involving the bone or implants are uncommon, but can be serious and may require surgery to resolve.
Failure to heal (non-union)
Sometimes, despite our best efforts, bone does not heal or heals much slower than expected. This may be due to damage sustained at the time of the injury, or other factors. Occasionally, further surgery may be required.
Poor alignment (mal-union)
This is where the bone heals, but not in a normal position. This is much more common in fractures managed with dressings than those treated surgically. Mild deformities are not usually a functional problem.
Implant failure
Although there are guidelines for which size implant should be used in which size of animal, it is often a judgement call. Too strong an implant can slow down healing by protecting the fracture, however, too weak an implant can lead to failure (bending or breaking of a plate for example). This most commonly happens due to something called cyclical loading, when repeated stress on the metal eventually leads to it giving way. It is one of the reasons why it is so important to rest your pet properly after surgery.
What is the outlook for pets with fractures?
In general, the long-term prognosis after a fracture is excellent. There are many factors that affect healing – being young and fit and having a simple break often lead to rapid healing. On the other hand, animals who are older, overweight or in poor health, and fractures which involve multiple pieces of bone, are more likely to heal slowly. If a fracture develops a non-union or significant mal-union, repeat surgery could be needed or amputation of the limb may need to be considered.
Two categories of fracture are known to carry a slightly more guarded prognosis; these are open fractures, in which the bone has pierced the skin leaving it open to infection, and articular fractures, in which the break involves a joint surface. These types of fractures are more complicated to treat.
Some animals will recover very quickly, whilst others take longer. Despite the bone healing, some pets are more willing than others to trust the previously broken leg. Using the limb less than normal can cause the muscles to get weaker, and your pet may benefit from physiotherapy or hydrotherapy in the recovery period. Every pet recovers differently, and your vet will be happy to discuss this in more detail with you.
Disclaimer
Please note that the content made available on this webpage is for general information purposes only. Whilst we try to ensure that at the time of writing all material is up to date and reflects industry standards, we make no representation, warranties or guarantees that the information made available is up to date, accurate or complete. Any reliance placed by yourselves is done so at your own risk.
Page last reviewed: 27th March 2024
Next review due: 27th March 2026