Complications

What are the potential complications of this fracture?

When the treatment of a fracture encounters a problem the case is described as "complicated". Most of the general complications that can affect a fractured femur are considered in some detail in Patient's Guide to Fractures. Here we focus on the problems that are specifically relevant to fractured thigh bones.

Malunion

When the bone heals with shortening, rotation or angulation it is said to be malunited. Before it heals it could be described as "malaligned" but this may be correctable. Once a bridge of bone has formed across the fracture the position of the fragments is set and will not change without surgery or re-fracture. This complication is very common where traction is the main method of treatment. It can occur with surgical treatment; fixing the fracture with malrotation is particularly common. The result of shortening is a permanent limp with one leg shorter than the other. If the fracture is malrotated the feet don't point in the correct direction and this also affects gait. If the fracture heals with an angle this tends to put uneven stress on the nearby joints and can lead to post-traumatic arthritis in the long term. There is often a combination of malalignments.

Malunion is only treatable by surgery to cut through the bone, re-align it in the correct position, and fix it. This is a major operation and needs careful consideration. In some situations it may be best to accept the problem and leave it alone.

Nonunion

This means that the healing process has failed and bone has not formed in the gap between the fracture fragments. Normally there is some x-ray evidence of bridging bone formation by three months. Healing is said to be delayed if there are no signs by then. However, healing can still occur without further intervention. Nonunion is the state when (in the opinion of the treating doctor) healing will not occur without intervention. It is often a difficult decision and may require CT scans to confirm the presence of a gap between the fracture fragments. This gap has scar tissue in it but no bone. The symptoms of a non-union of a thigh bone are pain made worse by bearing weight or stressing the leg. In extreme cases there is detectable movement at the non-union site.

Nonunion is more common with non-operative (traction) treatment of the injury but can occur after surgical fixation especially if there is a large gap between the fragments or an infection. If the fracture was initially treated nonoperatively the first line of treatment would be surgery to hold the fracture immobile. Usually this would be supplemented by bone graft or other material implanted to stimulate bone growth. If the bone has been treated with a locked IM rod the first line of treatment might be to remove the locking screws and allow the weight of the patient to compress the fracture site. This often improves the healing process. Alternatively the rod may be removed and replaced with a larger one, with or without bone grafting. The surgical treatment of non-union is a controversial issue and will vary according to the case. Non-union is usually an intolerable problem and treatment continues until the bone heals.

Infection

An infected fracture occurs when bacteria seed to the fracture site and start to grow in the blood clot near the injury. This happens most commonly with open fractures because of contamination. It also occurs after surgery because the skin barrier is breached. Very rarely bacteria spread in the blood stream to the fracture site and cause an infection in a closed fracture which has not been operated on. When the bacteria invade the bone (osteomyelitis) they are difficult to eliminate. Avoiding infection is the major reason for non-operative treatment. The infection rate following surgery may be as high as 2% in modern hospitals and a good deal higher in developing medical systems. Infection in a fracture is difficult to deal with and may affect the long term outcome. As a result surgeons were very hesitant to operate on fractures. Nowadays the benefit from surgery (straight bones, rapid healing and recovery of function) is considered to outweigh the risks of infection. There have been advances in the prevention of infection and in its treatment. Antibiotics are routinely used during and after most operations on fractures.

An infection in a fracture usually declares itself as increasing pain, swelling and tenderness at the site of surgery. Drainage of pus from the wound makes the diagnosis certain. The treatment is long term antibiotics to supplement the body's defenses and surgery to remove dead and contaminated tissue to give the defense a better chance. This operation is called debridement and may be followed by packing the wound with beads containing antibiotics. It may also be necessary to remove or change the hardware which is keeping the fracture still. Generally speaking, the treatment of infection is successful in suppressing it and allowing the bone to heal. However, the infection may arise again after many years, if it is not completely eliminated.

Venous Thrombo-Embolism (VTE)

After an injury nature activates the clotting system of the body to stop the bleeding. This may have the effect of causing blood to clot in the veins, especially if the circulation is sluggish and the limb is immobile. Clots in the deep veins (Deep Vein Thrombosis, DVT) may cause symptoms of pain, swelling and purple discoloration. However, quite often the condition does not show symptoms. The most dangerous situation is when the clots in the veins break off and travel in the blood stream to the lungs. This is called Pulmonary Embolism and may cut off the blood supply to the lung with fatal consequences.

VTE is relatively rare in thigh bone fractures treated operatively. It is made less likely by early mobilization of the patient after surgery. However, the nurses and doctors keep a careful watch for signs and symptoms. Treatment of the problem involves using medications that reduce the tendency of the blood to clot. These "blood-thinners" may be continued for months after the complication has been discovered. If it recurs then they may continue for life. More rarely, a filter is placed surgically in the main vein leading up to the heart to prevent any clots from getting to the lungs. Blood-thinners have their own set of associated complications so they are not used as a routine.

Compartment Syndrome

This is not common following a thigh bone fracture. Pressure builds up in the muscle compartments of the thigh resulting in severe, unrelenting pain made worse by active and passive movement. The treatment is to operate to relieve the pressure by decompressing the muscle compartments. If this problem is diagnosed and treated early the outcome is satisfactory.

[LINK: A Patient's Guide to Fractures]

Stiffness

Thigh bone fractures are accompanied by a great deal of damage to the surrounding muscles. If these muscles scar down to the bone as they heal they will not allow normal movement of the knee. When the treatment consisted of long periods of immobilization in traction or in a cast this type of stiffness was common. Extensive surgery was undertaken to free up the limb after everything had healed. Where the fracture can be stabilized by surgery, movement of the knee in the recovery period should prevent this complication.

Post Traumatic Arthritis

This is not common following isolated thigh bone fractures as the joints are not directly affected. If there is significant malunion or stiffness there may be a risk of arthritis in the long term.

Associated Injuries

Because it takes a lot of force to break a thigh bone it is not unusual for there to be more than one break in the leg. This may be obvious like a broken shin bone or it may be difficult to distinguish from the shaft fracture, like a hip fracture. Fractures of the knee cap are quite commonly associated, as are fractures and dislocations of the hip socket. Fractures of the bones of the foot may also occur with thigh bone fractures and may be inconspicuous enough to be missed in the initial assessment.