Types

Calcaneus

The calcaneus, or heel bone, is the most frequently fractured tarsal bone, accounting for 2% of all fractures seen in adults and more than 60% of tarsal fractures.

Avulsion fractures (3%) can occur by over-pull of the heelcord (achilles tendon) usually during a major effort in sports or jumping. It can be the result of fatigue failure with multiple repetitive effort.

A fracture occurring into the joint between the talus and the calcaneus(70%) is one of the most serious foot fractures. It is caused by axial over-loading, driving the talus (ankle bone) down into the heel bone. Motor vehicle accidents and falls from ladders are common causes. There is quite a high risk of other injuries with fractures of the other heel, fractures of the spine and injuries to the kidney all being quite common. Disruption of the heel pad is also common and compartment syndrome of the foot can occur. Because it makes a major weight bearing joint surface irregular, this injury may be treated by surgery to restore the joint to smoothness.

A fracture may also that does not involve the joint. This fracture is caused in a different way. A direct blow to the side of the heel or trapping and twisting the heel may cause a fracture which does not go into the joint. Most often these can be treated without surgery.

A fracture of the anterior calcaneus process is a rare fracture that can be caused either by avulsion of the attachment of a ligament when the foot is twisted inwards or by compression when the foot is twisted outwards.

A portion of the calcaneus that juts out to support the talus is called the sustentaculum. It may be broken in an accident in which the foot is twisted inwards while bearing a significant amount of weight.

Talus

A fracture of the head of the talus accounts for 5 to 10 percent of all fractures of the talus. This fracture is caused by a compressive force when the foot is pointed downwards. The fracture enters the joint between the talus and the navicular. If it is displaced it is often treated by surgery (ORIF), becasue it involves a joint surface.

A fracture of the neck of the talus is a serious injury. This fracture passes transversely across the talus and isolates the part of the bone that forms the ankle joint. Forces that bend the foot up beyond its limit are responsible for this pattern of fracture. Open fractures are common. There is a high incidence of avascular necrosis of the dome of the talus. Avascular necrosis is a condition where the blood supply to a bone is damaged. This results in death of the area of bone that is normally supplied by the blood vessels that are injured. Over time, this bone may collapse causing severe damage to the joint and post traumatic arthritis.

The lateral process is a small bump of bone on the outside of the talus which is the attachment of ligaments of the ankle joint and the subtalar joint. Severe twisting forces to these joints may tear the ligament (ankle sprain) or pull off the piece of bone (lateral process fracture). The treatment and outcome of this fracture depends on how much of the nearby joint surfaces are damaged.

The posterior process of the talus may be fractured. Either the inner (medial) or outer (lateral) side of the back of the talus may be broken off when the ankle is severely twisted. Ligaments of the ankle and subtalar joints attach here. The surface of the joint with the heel-bone may be damaged.

A fracture of the joint surface of the talus is called an osteochondral fracture. In some ankle sprains a portion of the joint surface of the talus can become separated from the rest. This is difficult to see on x-ray. In some cases the fragment will heal if the joint is immobilized. In others it may need to be removed.

Navicular

A cortical avulsion fracture may be caused by over-pull of muscle or ligament attachments. These injuries occur when the foot is twisted. Normally, they heal without intervention except for resting the foot. However, if the fragment is displaced 1 cm or more it is advisable to operate to replace it and fix it back in position.

A navicular tuberosity fracture is also an avulsion fracture caused by over-pull of the tibiallis posterior muscle. This is a powerful muscle that inverts (turns the foot inward) the foots and maintains the arch. Surgery is often required to replace and fix the fragment.

Fractures of the navicular body often pass through the joints with the talus, the cuneiform or both. If there is any displacement they need to be treated surgically with ORIF.

A stress fracture of the navicular is a relatively common fatigue failure fracture in athletes and military recruits who undertake repetitive training exercises that load the foot. Diagnosis is often delayed because these fractures do not initially show up on X-ray. Simply resting the foot for several weeks is usually successful treatment.

Cuboid

A isolated fracture of the Cuboid is relatively uncommon. The bone is more often broken when a major force injures the midfoot and fractures the cuneiforms or the talus and/or the navicular as well. Treatment depends on the overall situation.

The nutcracker injury results from a force pushing the foot outwards and crushing the cuboid between the calcaneus and the 4th & 5th Metatarsals. If the cuboid is badly crushed the outer border of the foot will be distorted even after the bone heals. In some cases the length of the cuboid can be restored by an open operation to reduce and fix the fracture then supplement the crushed bone with bone graft.

Medial Cuneiform, Intermediate Cuneiform, Lateral Cuneiform

Isolated fractures of these bone are quite rare but may occur from direct impact – dropping something on the foot. More commonly, fractures to these bones occurs in association with fractures of other bones of the midfoot and hindfoot. An injury that disrupts the tarsometatarsal joint often also causes fracture of one or more cuneiform bones.

One relatively common injury occur at the tarsometatarsal (Lisfranc’s) joint. Partial or complete dislocation with or without fractures of one or more of the metatarsals is called a Lisfranc Dislocation. It is caused by axial loading the foot when standing on tiptoe or by impact or twisting the mid-foot. It is sometimes difficult to diagnose on standard x-rays. Stress views of the mid-foot show that the joint between the 2nd metatarsal and the cuneiforms is disrupted. This is an unstable injury which often requires operative treatment.

1st – 4th Metatarsals

Injuries of these metatarsals usually occur as fractures of the neck region, shaft fractures or stress fractures. Neck fractures often affect more than one metatarsal bone and are caused by dropping a weight on the instep, kicking or loading when on tiptoe. Even though the fractures may be quite displaced they usually heal without intervention and cause no significant long term problems.

Metatarsal shaft fractures are also usually caused by impact or crushing. Treatment is individualized but many such fractures can be treated non-operatively.

Stress fractures occur in the proximal region of the metatarsal shaft. They are caused by repetitive activity and were first described in army recruits who were expected to undertake long marches and drill activities. These injuries are fatigue failures of the bone and usually heal if the activity which causes them is stopped and the foot is allowed to rest for several weeks.

Insufficiency fractures occur in people with osteoporosis and the metatarsal can break with very little force. These are fragility fractures which are a warning that there is a greater risk of spinal and hip fractures in the patient. Treatment of the fracture is often quite simple with rest and non-weight bearing resulting in healing. However, the patient should be assessed for osteoporosis and may need treatment for that condition.

Related Document: A Patient's Guide to Osteoporosis

5th Metatarsal

A very common foot fracture that sometimes occurs during an ankle sprain is the avulsion fracture of the tuberosity, or base, of the fifth metatarsal. The injury is caused by inverting or turning the ankle over - the same movement that occurs when an ankle sprain occurs. One of the muscles that attempts to prevent this is the peroneus brevis. Over-action by this muscle causes an avulsion fracture of the tuberosity of the 5th metatarsal where the muscle’s tendon attaches. This injury will heal without intervention and should be treated quite simply with rest and protection.

A more serious type of 5th metatarsal fracture is known as the Jones fracture. This injury is also caused by an inversion twist of the foot. It is a fracture of the upper end of the 5th metatarsal as well but slightly further out, or distal, than the avuslion fracture. This fracture also enters the joint with the 4th metatarsal. This fracture is more serious primarily because it may not heal and may require surgery.

Stress fractures can also occur in the 5th metatarsal. Patients may present with a painful outer border of the foot without a clear history of an accident. Although it seems very similar to the avulsion fracture, the stress fracture behaves very differently with a high rate of non-union. Some surgeons prefer to treat this fracture by surgery even if it is an acute injury; chronic injuries or stress fractures are very often treated by surgery (ORIF).

Phalanges (Toes)

The little bones that make up the toes are collectively called phalanges. Fractures to these bones are common and can be caused by kicking, stubbing the toe or when something is dropped onto the toe. The fractures can be roughly divided into those that affect the joint at one end or the other (intraarticular fractures) and those which do not (shaft fractures). Restoring the smoothness of the joint surface may sometimes require surgery (ORIF) but it is actually rare for either type of fracture to require operation. Most people do not put a lot of weight through their toes so they don’t have to heal straight.