The bone between the hip and the knee joint is called the femur. Growth plates are susceptible to developing fractures in immature animals. The sciatic nerve runs along the backside of the femur bone and may be injured by a sharp broken femur bone.
The most common cause of a femoral fracture is trauma such as being struck by a vehicle. Gun shot injuries not only will fracture the bone, but also will result in a dirty open wound. This could potentially result in infection and delayed healing of the bone. Also, if the fractured bone is sharp, it may penetrate through the skin and result in infection of the bone.
If the pet sustains a fracture without any known trauma, there may be an underlying disease that has weakened the bone, such as nutritional deficiencies. Foods that have too much phosphorus and too little calcium, or too much vitamin A, will make the bones weak. Some animals have an inherited collagen defect that weakens the bones resulting in bone fractures with minimal trauma. Bone cancer also can weaken the bone and predispose the pet to a spontaneous fracture.
For most fractures of the femur, a bone plate and series of screws are used to stabilize the fracture. This treatment provides the least aftercare for the client and a successful outcome in most cases. The metal implants can be removed one year after surgery in mature dogs and sooner in puppies. Femur fractures cannot be casted or successfully splinted. Either of these treatments will usually result in a failure of the bone to heal or inappropriate healing (misaligned bone).
Surgical repair of a fractured femur with a plate and screws offers multiple benefits over other treatments. These include a faster recovery; earlier use of the limb after surgery; a better chance to return to athletic activity; less risk of a second surgery being required; and better range of motion of the joints above and below the fracture. Uncommon complications include infection, non-healing of the fractures, breakage of the metal plate, osteoporosis of the bone, bone cancer induced by metal implants, and sciatic nerve damage.