Fractures of the Talus

The talus is a critical bone of the ankle joint. It connects the leg and the foot. The talus is involved in multiple planes of movement. It joins (articulates) the ankle joint and is responsible for the upward and downward movement (dorsiflexion and plantarflexion) of the ankle. In addition, it joins the heel bone (the calcaneus) where it is responsible for the majority of the inward and outward movement (inversion and eversion) of the foot. Injuries of the talus may therefore effect both the ankle and subtalar joint and affect multiple planes of movement of the foot and ankle. These injuries range from relatively minor chips or fragments that are broken off the edges of the talus to very serious fractures that can be quite devastating.

The goal of treating fractures of the talus is to maximize the movement of the ankle and subtalar joints, restore the anatomic dimensions of the bone and prevent arthritis of either of the above joints. This is not easy because of the magnitude of the fracture that commonly occurs in the most serious injuries. Arthritis may develop, or even worse, there may be a loss of blood supply to the bone. This loss of blood supply is one of the more devastating problems associated with fractures of the talus. In order for the bone to survive and heal after a fracture, it needs blood circulation. One of the problems commonly associated with certain severe fractures of the talus is that the blood circulation to this bone is damaged, leading to partial death of the bone (called avascular necrosis). Not all fractures of the talus lead to the development avascular necrosis. However, if this does occur it is commonly associated with the development of arthritis of both the ankle and/or the subtalar joint, as well as the collapse of the bone.

Treatment of fractures of the talus is quite varied. This ranges from immobilization of the foot in a cast or boot to surgery. If surgery is performed it is usually done with incisions and then the bone is put back together with a procedure called open reduction and internal fixation. Pins and/or screws are used to reduce and hold the bone in place.

Recovery after fractures of the talus can be prolonged. Walking and weight bearing on the foot cannot occur for eight to twelve weeks. Once the bone is healed, however, exercise and physical therapy is initiated to maximize the function of the ankle. If avascular necrosis of the bone occurs then one has to be more careful with the type of exercise and activities that are initiated. Walking and exercise are still permitted. There are surgical procedures that can be performed if avascular necrosis develops to try to improve the blood circulation to the talus bone.

Problems after talus fractures

Fractures of the talus can be quite devastating. These are difficult fractures to treat, and even with good correction and fixation of the fracture, numerous complications can occur. Some of these are as a result of deformity, some from arthritis, and some occurring when the blood supply to the talus bone is damaged.

1. Ankle arthritis. Arthritis of the ankle can occur. The ankle joint moves in the up and down direction, and if arthritis of the ankle occurs, this will affect the ability of the ankle to move. Take a look at the section on arthritis of the ankle, where you can read about a more complete discussion of the problem.
   
   
2. Subtalar arthritis. The joint underneath the talus bone is called the subtalar joint. This is the joint which joins the talus to the heel bone called the calcaneus, and is responsible for the in and out movement of the back of the foot. This movement is called inversion and eversion. If arthritis of the subtalar joint occurs, then there will be more pain on in and out movement of the foot than the up and down movement. If arthritis of the subtalar joint occurs, then the most common operation to correct this is a fusion (gluing together) of the subtalar joint. This operation results in correction of the pain in the back of the foot, but the foot is stiffer, and little if any in and outward movement of the foot remains. Provided that the bone is healthy, the fusion is not too complicated. Unfortunately, the talus can collapse in size, and if this occurs, then special types of bone graft need to be used to correct the deformity and make sure that healing occurs without losing more height of the back of the foot.
   
   
3. Deformity of the foot. One of the problems with fractures of the talus, is that in addition to the main fracture, there are often additional smaller fractures on the inside of the bone. When the fracture is fixed, it can be difficult to reposition the bone correctly, and deformity occurs. Typically, the foot turns inward, and what happens is that more weight is placed on the outside of the foot, which can be terribly painful. Some doctors have tried to correct the deformity by cutting the talus bone and inserting a bone graft, but this rarely works, and pain and stiffness of the foot and ankle continues. The only reliable way to correct this deformity (called a varus deformity) is to fuse three joints in the back of the foot. This operation is called a triple arthrodesis.
   
   
4. Avascular necrosis of the talus (AVN). The talus bone as every other bone depends on a blood supply to remain alive. When the talus is fractured, this blood supply can be torn, leading to death of the talus. This dead bone can be total, and include the entire talus, or patchy, without much destruction to the bone.

Avascular necrosis of the talus

In these images, are the very typical appearance of the bone associated with AVN of the talus. These are not an XR but an MRI, which is the most useful imaging test to diagnose AVN. Note the presence of the white or black irregular shadows in the middle of the talus, which is the dead bone.

This is a typical fracture of the talus. The fracture line is irregular, but there is not very much displacement of the two pieces of the fractured bone. This is called a minimally displaced fracture, and although AVN could develop, it is less likely.                 These are also examples of a fracture of the talus with very little displacement. The development of AVN is unlikely in these fractures.                   On the left, is an XR of a talus with fracture where the main part of the talus in the back (called the body of the talus) is dislocated. The same applies to the picture on the right, which is a CAT scan where the fracture is very displaced. In both these fractures, the development of AVN is more likely.                 In this fracture the entire body of the talus has dislocated out of the back of the ankle, and AVN develops in 100% of these fractures.

The fracture on the left has been treated with screws. Although the fracture has healed and the talus is in very good position, AVN has developed. Note the overall color of the talus bone in the front (which is normal, compared to the white color of the bone in the back, which is diagnostic of AVN.

The care of the limb after any fracture in the foot and ankle is based upon the premise that a limited amount of standing, walking and bearing weight on the foot is permissible. This makes sense, since pressure on the fracture with walking before the fracture has healed will lead to a shift in the bones resulting in a non-union, or a malunion. This has particular relevance with the fracture of the talus where one is concerned about the development of AVN, since the surgeon is understandably concerned about the consequences of bone healing if AVN occurs. If AVN does occur, the talus can break up into small pieces, fragment and collapse. This is not however predictable. The majority of fractures which develop AVN do not go on to collapse, and the AVN is limited to small segments of the talus.

Orthopedic surgeons were understandably concerned about the development of AVN, and as such limited the patient from walking on the leg at all, worrying about the possibility that AVN would progress and lead to collapse of the bone. In fact, this has never been demonstrated to be necessary, and once the fracture has healed, bearing of weight on the leg is actually permissible. There is no evidence to suggest that the patient has to remain off the foot using crutches for an indefinite period of time to prevent the talus from collapsing further. The foot may need to be protected, using a boot or a brace, and certain activities with impact on the leg may need to be restricted, but walking should be acceptable. Once collapse of the talus occurs, then problems begin, including arthritis and deformity. These are very difficult to correct surgically, but with newer reconstructive treatments available have been very successful.

This is an example of a very severe form of AVN of the talus. Most of the talus is white, the shape of the talus has changed, since it has collapsed, and there is very little cartilage space left in either the ankle or the subtalar joints, indicating severe arthritis. The arthritis and the AVN was treated as is shown in the pictures below by removing the screws which were inserted to fix the original talus fracture, and then by inserting screws into the back of the joints of the foot to fuse the joints together. This operation is called a triple arthrodesis.

A triple arthrodesis has been performed here. This operation only corrects some aspects of the problem, the arthritis of the hindfoot and the deformity. It does not correct the arthritis of the ankle, which still remains.

This patient was treated for AVN of the talus with a triple arthrodesis, seen on the left XR, and then followed four months later with a total ankle replacement seen in the right hand two pictures. The ability to perform a total ankle replacement depends to some extent on the quality of the talus bone, and the severity of the AVN.                 Severe AVN in this patient was associated with collapse of the talus, and arthritis of both the ankle and the subtalar joints. Traditional treatment has been to fuse both the ankle and the subtalar joints. The problem with fusion, is that there is limited blood supply into the talus, and the success of the fusion is not always that good.                   The patient above was treated with a subtalar fusion with a specialized bone graft inserted into the subtalar joint, in order to lift up and elevate the height of the back of the foot. 5 months later, once the first surgery was done successfully, a total ankle replacement was performed. Look at the right hand picture, and you will see that the screws from the fusion and the fracture have been removed and the ankle replacement inserted.                 This is the range of up and down motion (called dorsiflexion and plantarflexion) of the ankle following the total ankle replacement after a fracture of the talus associated with AVN.

The problem with AVN of the talus, is that blood supply does not simply return, and there are very few ways to improve the circulation to the talus. Below is a list of some alternative ways we are able to treat this condition.

1. Fusion of the ankle. This has been a treatment recommended but of course glues together the ankle and limits the up and down range of motion permanently. The fusion is not easy to accomplish, and the success rate of this type of surgery can be unpredictable.
   
   
2. Total ankle replacement. Total ankle replacement is now an accepted treatment for ankle arthritis, but cannot always be performed if AVN is present. The ankle replacement must have a good bone to sit on, and if the AVN is extensive, it cannot be performed. However, as illustrated here, if a fusion of the subtalar joint is performed first, there is often sufficient bone underneath the talus then to support the ankle prosthesis.
   
   
3. Drilling of the talus. There is a lot of evidence that by creating a hole with either a drill or a device that looks like a kitchen tool used to core an apple, that we can increase the blood supply to the talus. The drilling creates little holes and channels that allow tiny little blood vessels to grow and improve the blood supply to the talus.
   
   
4. Muscle flap. All muscle has a blood supply to it in order to stay alive. We have developed an operation which moves a small muscle on the side of the outside of the foot into the talus. This is a new procedure, and with the short term follow up of these patients, the results seem to be good.
   
   
5. Free vascularized bone graft. It is possible to take a tiny blood vessel attached to a piece of bone and using the microscope, to transplant this into the talus.