Complications

What are the potential complications of this fracture?

Both the injury and its treatment may have features that complicate recovery. The general complications of fractures are described in more detail in Patient's Guide to Fractures. These include fat embolism, blood clots, neuro-vascular injury, compartment syndrome, nonunion and malunion. Here we will discuss the complications that are particularly related to knee fractures.

Infection

After an open fracture or surgery the skin, the body's first line of defense against infection is breached. Open fractures must be thoroughly cleansed and all dead and contaminated tissue removed. Antibiotics are given by intravenous injection. The risk of infection after this treatment varies according to the severity of the injury from 5% to 30% for severely contaminated wounds with compromised blood supply. The risk of infection in the surgical site after a fracture operation is about 2%.

In the case of knee fractures infection may involve the knee joint and this can cause major consequences. Unlike bone the joint surface does not re-grow. If the natural joint surface is damaged by infection that damage is permanent. Special precautions such as drainage are often taken to make sure that pus does not build up under pressure in the knee joint.

The signs of infection in a wound include increasing pain and tenderness. The wound margins are red and the wound may drain pus. The complication will be treated aggressively with further surgery to open up the wound and remove infected tissue, irrigation of the joint and drainage. In some situations an infected wound will be packed with beads containing antibiotics to create a high local concentration of the drug.

The fixation usually remains in place; an infected nonunion is even more of a problem. In most cases this treatment is successful in suppressing or eliminating the infection and allowing the fracture to heal. Once it has healed the fixation can be removed and this usually results in complete healing of the infection. In a small proportion of cases infection may persist and flare up again in the future.

Post traumatic osteoarthritis

If the joint surface is damaged, crushed or fragmented by the injury, full recovery of a smooth normal joint cannot be expected. Unlike bone, joint surface does not re-grow to fill in any gaps caused by the injury. In some fractures it may prove impossible to move all the fracture fragments back into place and keep them there until healing has occurred.

Irregularity of the joint or damage to the surface will cause increased wear-and-tear arthritis of the knee. This post traumatic osteoarthritis may develop quickly or can develop years or decades after the fracture. The symptoms are aching pain, swelling of the joint and loss of the full range of movement. The joint margins are tender and there may be a grinding sensation in the knee. One side of the knee may wear down faster causing angular deformity of the knee and a sensation of laxity.

The first line of treatment of osteoarthritis of the knee joint is medication to reduce the symptoms and allow you to function fully. Sometimes braces are used to shift weight-bearing from the most injured part of the joint. For end-stage post traumatic osteoarthritis, a total knee replacement is a successful treatment.