Femur fracture

The thigh bone between the hip joint above and knee joint below is called the femur. Fractures of the femur are the most common ones seen in veterinary practice and usually result from blunt trauma (such as a car accident). There are many types of fractures, ranging from ones that involve the joints, to ones that break across the cartilaginous growth plate and others that involve the shaft or middle of the bone. Traditionally, many femur fractures are repaired using a smooth pin down the centre of the bone called an IM pin. Be careful as the complication rates using an IM pin are high. Use of a plate and screws is far superior. The screws are threaded and engage the bone so that implant loosening is not a likely. More recently a device called an interlocking nail has become available for both cats and dogs. This implant is the ‘gold standard’ in human orthopaedics and can be use for fenmur fractures in animals too.

Pelvic fracture

The pelvis can be thought of as a rectangular box of bone connecting the spine to the back legs. It holds all of the important muscles for locomation and allows weight to be transferred from the legs to the spine. Fractures of the pelvic bones (ileum, ischium, pubis, sacrum) are common after blunt trauma such as a car accident. The reasons for your local vet to refer you to a specialist surgeon would include: severe pain, involvement of the hip joint, breaks on the left and right sides and collapse of a segment of bone causing narrowing of the pelvis. Some minor fractures can be effectively managed with cage rest for 6 weeks. Surgical repair should be performed by an experienced vet who has ample time and advanced equipment. There are a range of implants that are used to repair these breaks as you can see below. The outcome should be very good and pets should enjoy a relatively normal pain-free life after pelvic fracture surgery. The chest and abdomen should also be checked (x-rays, ultrasound, CT scan) for additional injuries if you know your pet has been hit by a car at high speed.

Radius/Ulna Fracture

The two bones in the forearm are called the radius and ulna. They act together to share the load between the elbow above and the wrist below. There are several different fracture patterns that can develop in dogs and cats. The most common injury is a transverse break across the width of the bone creating two equal halves. It has been shown that use of splints and casts for these fractures leads to a high rate of problems such as rub sores and bone healing complications. The goal of surgery is to quickly restore skeletal strength and promote early return to fuction. The plates and screws used do not rust or corrode. Internal implants like these are permanent and do not require removal. The benefit of having internal implants is that they are well tolerated by animals and there is nothing to chew at on the outside of the leg. Sometimes temporary external frames are required to span a highly broken section of bone. These frames can be applied closed without having to surgically approach the bone inside. The frames permit walking and getting wet.

Tibia fracture

The shin bone is called the tibia and connects the knee to the foot. It has a small second bone attached called the fibula. There are many types of tibia fractures that can all be repaired to restore full athletic function. Starting from the top of the bone we commonly see growth plate fractures that are repaired using parallel pins. Often we can align and place these pins closed using a special machine called an image intensifier (fluoroscopy unit) to show where the implants are during surgery. This ensures excellent implant placement. The middle of the bone can break and this requires stabilisation using a bone plate and screws. It is important to ensure the plate is long enough and well positioned on the bone surface (contoured). Growth plate fractures at the bottom of the tibia are repaired using pins and fluoroscopy as described above. Finally dislocated ankles (most common in cats) can be fixed using a temporary supportive bandage or frame (circular ring external fixator).

Humerus fracture

The upper arm bone in the front leg is called the humerus. This bone has an unusual shape and fractures are more difficult to repair than the other bones in the legs. If the centre of the bone breaks we typically repair the fracture using a contoured plate and screws made of stainless steel. These implants are stiff and function to hold the two bone segments rigidly while the bone heals back to normal strength. Sometimes, if there are many large fragments, we place wire around the outside of the bone first and then insert a large smooth pin down the inside of the canal (interlocking nail). Smaller breeds can develop a joint fracture after being dropped by children, we call this a humeral condyle fracture. The ideal reair for this one uses a compression screw and pin as shown in the sketch. Again, due to the irregular surfaces of this bone, it is very important to have an experienced vet perform this surgery.

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