Puppies and kittens have growth plates at the end of the femur bone from which the bone grows. Growth plates are susceptible to developing fractures in immature animals. One such growth plate located at the bottom of the femur bone is called the distal femoral physis.
Signs and diagnosis
This type of fracture usually occurs in dogs and cats that are less than one year of age. The most common cause of a femoral fracture is trauma such as being struck by a motorized vehicle or taking a fall. Affected pets will bear minimal to no weight on the fractured limb. The lower part of the thigh, near the knee will be swollen, painful to touch and may be crepitant (crunchy) when the knee is flexed and extended. The diagnosis of this type of fracture is made with X-rays of the limb.
Distal femoral physeal fractures always require surgery for a successful outcome. Without surgery the pet will usually develop a stiff limb that has poor function. This type of fracture is also not amenable to a splint or cast. Surgery should be done as soon as possible, so that the broken end of the bone does not get worn down, thus preventing the fracture from fitting together properly. In addition, chronic fractures may be very difficult to put back together, as the tissues around the bones become permanently contracted. Surgical repair of a distal femoral physeal fracture requires an incision located on the outer side of the lower thigh and knee. The bones are realigned and two pins are inserted to keep the fracture in place.
Primary repair of the fracture has been reported to be successful in 93% of the cases; whereas, no surgery will result in persistent lameness and a poorly functioning limb. Uncommon complications include infection, breakage of the pins, migration of the pins (requiring removal or replacement of the pins), and collapse of the fracture site.
For more information on this subject, speak to the veterinarian who is treating your pet.