Complications

What are the potential complications of this fracture?

Complications are events which make the process of healing from a fracture more lengthy or difficult, or which may compromise that process. Some of the activities that patients are urged to do following a fracture, such as moving the injured part early even though it hurts, may seem meaningless or even cruel. They are intended to reduce the risk of complications.

This section on complications goes into detail not because the complications themselves are common, but because avoiding the complication is one of the foci of treatment. A full account of the complications of fracture healing is presented in the Patient's Guide to Fractures in General.

Venous Thrombo Embolism (VTE)

Following an injury, the body activates the blood-clotting mechanism, circulation in the blood vessels may be slowed by swelling and the patient may be immobilized, reducing circulation even more. This combination may result in blood clots forming in the veins of the legs and the pelvic region. These clots themselves reduce the speed of blood flow in the veins so more clot may form. If the clot continues to grow and extends up into the large veins of the thigh and pelvis there is a risk that parts of the clot may break off, float up in the veins and lodge in the lungs. This is called embolism and can be very dangerous, affecting the blood flow to the lung.

VTE is a feared complication of pelvic fractures because the severity of the injury makes clotting of the pelvic veins more likely and there is often a need for bed rest. As early as possible, patients are encouraged to move their legs to improve circulation. Early in the recovery from a pelvic fracture patients are mobilized to sit in a chair or get up on crutches. Anti-coagulant medication may also be used if there is evidence of a blood clot or a very high risk.

The treatment of established VTE generally involves long term anti-coagulation medication. In selected cases it may be necessary to insert a filter into the venous system to stop clots from getting as far as the lung.

Nonunion

It is rare for the bone to fail to heal but movement may persist at the site of injury to the posterior ligaments in the sacroiliac complex or the pubic symphysis. This situation may result in pain on weight-bearing, a feeling of instability or upward shift of the pelvis. Operation or re-operation to fuse the unstable joint may be required.

Malunion

A situation in which the pelvic ring heals with persistent and symptomatic deformity is called malunion. The distortion may result in one leg being shorter than the other or one half of the pelvis being rotated. This result may be accepted although it is not optimal. Operating on the pelvis to restore the normal shape is a difficult, complex procedure. It may be preferable to use a shoe lift to even up an leg length discrepancy.

Malunion of the acetabulum is also a serious problem when it results in an uneven joint surface. Further surgery is often recommended in this situation. An attempt may be made to take down a healing fracture and make the inside of the hip socket smooth. Alternatively, after healing, a hip replacement operation or a hip fusion may be done to make the leg comfortable and functional.

Nerve Injury

The nerves that pass over the sacrum as they exit from the spine may be injured when the pelvic ring is fractured. It is important to establish the existence and extent of this component of the injury at the beginning. Loss of sensation in groin or incontinence may be quite difficult to establish in an unconscious patient with a catheter in place. Later, these impairments may be significant long term issues. If the nerves are stretched there is a good chance of recovery; if they are torn the outlook is less optimistic.

Heterotopic ossification (HO)

Pelvic fractures are often accompanied by massive bleeding and injuries to the muscles of the region. Normally this blood clots and eventually forms scar tissue. For reasons unknown, bone may develop in the scar tissue. Because this bone formation (bone formation is referred to as ossification) is out of place, it is known as heterotopic ossification. It is common after pelvic fractures and even more common if they are treated surgically.

Early in the recovery period the wounded area may be swollen, tender and feel hard and "woody". Within 6 weeks of injury X-rays show bone forming in the tissue. Although little is known about the fundamental reasons for this problem, it is clearly an inflammatory process. If one attempts to perform surgery at an early stage and remove the HO, it creates yet more inflammation and bone formation.

The best ways to limit HO are to use anti-inflammatory medication or radiation. Because of the potential side effects from these treatments they are not used as preventative measures (or prophyllaxis) in all cases but may be used once the diagnosis is established or suspected.

The bony lumps that form in the tissues may not cause symptoms. If they do, it is best to wait 18 months for the inflammatory process to settle completely before undertaking surgery to remove the heterotopic bone.

Infection

Contamination of the fracture, either at the time of the original injury or at surgery may result in bacterial infection. The wound tends to be swollen, red and more tender than normal. The patient runs a temperature and pus may drain from the wound. Culture of the pus or blood cultures may show up the bacteria that causes the problem.

High doses of antibiotics are needed for a long time when a surgical site infection (SSI) is present. It frequently requires further surgery to remove dead and contaminated tissue and drain the wound so pressure does not build up. It may be necessary to remove or revise (change) the implants if they are infected; more often they are left in place until the bone has healed because a stable fracture is more resistant to infection than an unstable one. The wound may require repeated surgery to wash out the infected material. Antibiotic beads or pellets can be used to maintain a high local concentration of drug in the wound. This combination of measures is usually successful in suppressing or eliminating the infection.

Once the fracture has healed the implants may be removed to eliminate foreign material in the wound and allow the body's defenses to clear up all the bacteria. SSI is a feared complication which requires prolonged treatment and more surgery, but the outcome is usually satisfactory.

Post Traumatic Arthritis

When the hip socket (acetabulum) is involved in the fracture, the joint surface may be crushed or fragmented. It may be impossible to restore the joint surface to smoothness. The medium and long term result of this may be premature wearing out of the hip joint. The remaining joint surface is worn away and the hip becomes painful and stiff. Avoidance of this outcome is the intent of surgery on acetabular fractures but it is not always successful.

The length of time a damaged hip joint will be functional after an acetabular fracture is unpredictable. The symptoms may be controlled by anti-inflammatory or pain medication for many years. The indications for further surgery to treat post traumatic arthritis are unbearable or relentlessly progressive symptoms, particularly of pain and loss of mobility. In a young person with a heavy job, consideration may be given to fusing the hip joint which gives a painless, strong and durable result. In other circumstances a hip replacement may be offered as this gives predictably good results as long as it is not over-loaded.