Complications

What are the potential complications of this fracture?

In this guide we will discuss the complications that significantly affect the management of ankle fractures. For details of other potential problems please see A Patient's Guide to Adult Fractures. We describe complications not because they are common but because the management of your ankle fracture is focused on avoiding them. For example, it may seem strange to be encouraged to move your ankle while it is still sore and swollen; but this helps avoid complications like compartment syndrome or subsequent stiffness.

Related Document: A Patient's Guide to Adult Fractures

Compartment Syndrome

When the swelling inside the muscles of the leg reaches a critical point the blood supply to the muscles gets cut off and the muscle tissue dies. This is rare but it can happen with cast treatment of ankle fractures especially if the cast gets too tight. The main symptom of this condition is unremitting pain that does not respond to medication. The pain is made worse by moving or stretching the ankle or even the toes. If it is diagnosed quickly and treated urgently by surgery to release the pressure, this problem recovers well. However if parts of the muscle die there will be some long term impairments of the muscle function. The nursing observations to check your foot, wiggle your toes and make sure all is well are done with this complication in mind.

Malunion

Healing of the fracture in an incorrect position is quite common when an ankle fracture is treated nonoperatively. The ankle mortise may end up wider than it should be, there may be changes in the rotation of the ankle mortise or irregularities in the joint surface. The significance of these problems depends on the age and expectations of the patient. In a young patient there is concern that malunion would predispose to premature wear of the joint (post traumatic osteoarthritis). It is rare for a healed fracture to be operated on to correct malunion; in most cases the likelihood of malunion is identified earlier before the fracture heals.

It is not uncommon for patients who were initially treated in a cast to have surgery when follow up shows that the fragments are going to heal in an incorrect position. The main purpose of close follow up of an ankle fracture is to detect this complication and correct it early.

Nonunion

Nonunion of a medial malleolus fragment is more common than the fibula. There is often some bony reaction around the nonunion site not just a persistent gap.

Failure of one or other of the ankle fractures to heal is not common. When present it leads to persistent pain and tenderness at the nonunion site. This is normally treated successfully with surgery for open reduction, bone grafting and fixation. The delay in healing may make full recovery of strength and range of motion more difficult.

Post Traumatic Osteoarthritis

Premature wearing out of the ankle joint does occur after ankle fracture. In most cases this is because the injury itself caused damage to the joint surface of the talus or tibia or both. After healing of the fracture the patient has persistent aching and stiffness. X-rays show loss of the joint surface and the development of spurs and loose bodies in the joint.

Most people can manage this problem with medication and a small loss of activity. In a small proportion of cases it is severe enough to require surgical treatment. At present the standard treatment is fusion of the ankle joint to prevent all movement between the talus and the tibia; the possibility of using a total ankle replacement operation in this situation is being investigated.

Infection

Surgical site infections occur in approximately two percent of operations performed under modern conditions. Because surgery is done for a high proportion of ankle fractures it follows that a few of these procedures will go on to get infected. It is more common with Pilon fractures because of more extensive soft tissue damage and greater exposure of the bones. The wounds remain red, swollen, and tender for longer than normal and may discharge pus. Infection is determined by culturing bacteria from the surgical site.

Treatment for infection will include long courses of antibiotics. It may also include further surgery to drain the wound and redo the fixation. The hardware is usually remains until the fracture heals. It is then removed to help eliminate the infection. With aggressive treatment of infection this situation may heal with no long term problems. However, in a small proportion it is difficult to get rid of the infection.

Hardware Failure

The surgical implants used to hold the fracture fragments in position after surgery are made of metal and subject to metal fatigue. As you know, if you repeatedly bend a piece of wire it will quite quickly break. If you load the metal implants holding your fracture together by putting weight on your injured ankle you run the risk of causing metal fatigue in the plates, screws or wires. It may not hurt to put weight on the ankle right up to the moment when your fixation hardware fails. The the fracture comes apart and you may be back to square one with recovery. If this happens you may need repeat surgery. If the fracture fragments have remained in good position you’re ankle may need to be immobilized in a cast. There is a higher risk of malunion and nonunion with hardware failure and a higher risk of surgical site infections with a second operation. When you are asked not to bear weight, it is not a frivolous request.