Metatarsal fracture: Description
Metatarsal fractures account for around a third of all foot fractures, and mostly affect athletes. The fifth metatarsal bone is most frequently fractured. Doctors refer to this type of metatarsal fracture as a Jones fracture – after the surgeon Sir Robert Jones (1857 to 1933). Several metatarsal bones are often affected by the injury.
The five metatarsal bones
The metatarsal bones are numbered systematically from the inside to the outside (Metatarsalia I to V):
The first metatarsal bone (Os metatarsale I) is connected to the big toe. It is shorter, wider and more mobile than its neighbors and, under normal conditions, bears about half of the body weight. If the first metatarsal is broken, the force was usually so great that the surrounding soft tissue is also damaged. In addition, other metatarsal bones are usually also affected by the fracture – an isolated metatarsal fracture of the first metatarsal bone is rare.
The middle metatarsal bones (metatarsals II to IV) are particularly responsible for transmitting force during gait.
The long fibular muscle (musculus fibularis longus) attaches to the fifth metatarsal bone. This serves to move the metatarsal bone in the direction of the sole of the foot.
The Lisfranc joint forms the boundary between the tarsus and metatarsus. It is part of the longitudinal and transverse arch of the foot and is therefore exposed to considerable dynamic and static loads.
Metatarsal fracture: symptoms
Typical symptoms of a metatarsal fracture are pain in the metatarsal area. The exact location of the pain depends on the type of fracture. In the case of a Jones fracture, for example, pain tends to occur centrally in the area of the lateral edge of the foot. A pressure pain can also be felt above the affected metatarsal bone.
Due to the pain, the fractured foot can hardly bear any weight. It is also swollen in the metatarsal region. A hematoma (bruise) often forms in the midfoot, which often extends to the toes. Sometimes the longitudinal arch of the foot is flattened and there is often an incorrect load when rolling. Caution: If the ankle is broken, similar symptoms may occur.
If such symptoms occur, it is advisable to see a doctor immediately – a metatarsal fracture is often recognized too late and only diagnosed months after the injury. However, early diagnosis and treatment are important so that the foot can heal without pain and no post-traumatic arthrosis develops.
Metatarsal fracture: causes and risk factors
Other causes are less common: For example, a metatarsal fracture can turn out to be a stress fracture (fatigue fracture, march fracture). This occurs particularly in people who put their feet under intensive strain, for example through aerobics, ballet or dancing. Runners also very often suffer a stress fracture if they increase their training load too quickly. In such an overload-related metatarsal fracture, the second to fifth metatarsal bone is usually broken.
In a metatarsal fracture, different sections can be affected by the injury, which often allows conclusions to be drawn about the mechanism of the accident:
Metatarsal fracture: heads
The heads of the metatarsal bones are adjacent to the toes. If the metatarsal is broken in this area, a direct force is usually responsible. A shortening can be seen, often with an axial deviation or rotation. If the injury is caused by the foot getting caught somewhere or hitting an object, the metatarsophalangeal joint may also be dislocated.
Metatarsal fracture: subcapital
Cervical or subcapital fractures in metatarsals are often displaced, usually towards the sole of the foot or to the side. The cause is usually a lateral shearing mechanism or an oblique direct force.
Metatarsal fracture: Shank
Metatarsal fracture: Base
The base fracture usually occurs as a result of direct force. It is often part of a Lisfranc dislocation fracture (see below).
In a simple metatarsal fracture, the base of the fifth metatarsal bone is usually broken. The fracture pieces often shift as the tendon of the long fibular muscle pulls the upper piece of bone upwards.
Metatarsal fracture V: Avulsion fracture
An avulsion fracture (avulsion fracture) can occur in the fifth metatarsal bone. It is usually the result of an inversion trauma, as the tendon of the long fibular muscle pulls on the fifth metatarsal, causing a fracture at the base. The avulsion fracture often occurs in younger patients as a result of a sports injury and in older patients as a result of a fall.
Metatarsal fracture V: Jones fracture
A Jones fracture can also occur on the fifth metatarsal bone – a fracture at the transition between the diaphysis and metaphysis: the diaphysis is the bone shaft, the metaphysis is the narrow area between the bone shaft and the end of the bone (epiphysis). A Jones fracture can occur, for example, if the foot is twisted and twists when walking on tiptoe.
Lisfranc dislocation fracture
Metatarsal fracture: examinations and diagnosis
Accident victims usually suffer several different injuries, which is why a metatarsal fracture is often overlooked. The foot injury is sometimes only discovered by chance years after the accident. This is precisely why you should consult an orthopaedic and trauma surgeon at the slightest suspicion of a metatarsal fracture.
Medical history
To diagnose a metatarsal fracture, the doctor will first ask you about the circumstances of the accident and your medical history. Possible questions include:
- What exactly happened in the accident?
- Do you have any pain?
- Does the pain occur with exertion?
- Did you already have symptoms before you broke your foot (e.g. pain or restricted movement in the foot area)?
Physical examination
Immediately after the accident, a metatarsal fracture can be identified by the clear deformity. At a later stage, however, the often massive swelling can make the diagnosis more difficult. During the examination, the doctor also looks for possible accompanying injuries to the soft tissues, nerves and tendons of the foot.
Imaging procedures
If the X-rays are not conclusive enough, the doctor will also order a magnetic resonance imaging (MRI, also known as magnetic resonance imaging) and/or a computer tomography (CT) or scintigraphy (a nuclear medicine examination).
The doctor will also order an MRI, a scintigraphy and/or a vascular X-ray (angiography) if the metatarsal fracture is due to fatigue (stress fracture) or is caused by disease. The latter can be the case with bone tumors or Charcot foot (also known as diabetic neuropathic osteoarthropathy, DNOAP).
In the case of a fatigue fracture, diagnosis is often difficult at first because no fracture gap is visible. Only later, when the bone reacts to the fracture and forms a callus (consisting of newly formed bone tissue), can the fracture be localized. With the help of an additional MRI scan of the foot, an earlier diagnosis is possible.
Metatarsal fracture: treatment
If the metatarsal is broken, the aim of treatment is to get the foot pain-free and fully weight-bearing again as soon as possible. This does not necessarily require surgery. Surgery is only recommended if the fracture is very displaced.
Conservative metatarsal fracture treatment
The foot is therefore initially stabilized from the outside with hard soles, soft cast (a support bandage) and tape bandages. The cast must be worn for about six weeks. Depending on the type of fracture, the foot can be put under weight after about four weeks. The doctor monitors the healing process by means of regular X-ray examinations.
In the case of a metatarsal fracture V in the form of an avulsion fracture, it is sufficient for the affected person to wear a so-called stabilizing shoe or a firm shoe sole to protect the foot.
In the case of a minimally displaced Jones fracture, the foot can initially be immobilized for six weeks in a cast shoe. The patient can put full weight on the foot, as the cast shoe is very stable and the upper ankle joint remains freely movable. After this, the foot can be fitted with immobilizing bandages until it is functional again.
Most stress fractures can be treated conservatively. The foot should be immobilized in a cast for about six weeks.
Surgical metatarsal fracture treatment
If the fracture fragments are too displaced, surgery is required. The bone fragments are aligned and stabilized with the help of screws or plates. The operation usually only requires two days in hospital. Regular X-ray checks show when the foot can be put under increased weight again.
If the remaining metatarsal bones are fractured, the bone is realigned in a closed manner and fixed under the skin with so-called Kirschner wires. If the bone fragments cannot be aligned in this way, open surgery must be performed. As the first metatarsal bone primarily stabilizes the foot, it must be fixed particularly early and well in the event of a fracture.
Lisfranc dislocation fracture
In the case of a fracture of the Lisfranc joint, the fracture must be realigned openly. The fracture site is usually at the base of the second metatarsal bone. This is then aligned and provided with two cribbed wires from the side for stabilization. The bases of the metatarsal bones are then fixed to the tarsal bone row with screws.
If there is severe soft tissue damage, an “external fixator” is used. The Schanz screws are inserted into the first and fourth metatarsal bones and into the tibial shaft.
Metatarsal fracture: course of the disease and prognosis
The healing process for a metatarsal fracture can vary considerably. The duration and course depend on the type of fracture. Whether soft tissue has also been damaged also plays an important role.
Metatarsal fracture: complications
In the case of a comminuted fracture or if several metatarsal bones are broken and could not be realigned correctly, a post-traumatic splayfoot and flatfoot can develop.
If cartilage has also been damaged in the metatarsal fracture, osteoarthritis can develop despite good treatment. In the case of a Jones fracture, pseudoarthrosis can occasionally occur, i.e. the bone fragments do not grow back together completely.
In the case of open fractures, osteitis (bone inflammation) can develop as a complication. If the metatarsal fracture is accompanied by crush injuries, there is also a risk of compartment syndrome.
