Metacarpal Fracture: Causes, Symptoms, and Treatment

Introduction:

A fracture refers to a partial or complete break in the continuity of a bone. Metacarpal fracture involves a break or crack in one of the metacarpal bones located in the palm. They are among the most common fracture types, with increased incidence in people indulging in contact sports such as boxing and football. They are mostly simple fractures that leave the skin intact and are managed well without surgery. If this fracture is not managed timely and appropriately, it can lead to various hand deformities. This article discusses metacarpal fracture and its management in detail.

Where Is the Metacarpal Bone Located?

Metacarpal bones are the five long and thin bones in the palm between the wrist and the fingers. Due to the structural characteristics of long bones, they are classified as long bones. Each of the metacarpal bones contains a shaft (the elongated middle part of the metacarpal bone), a distal base (the end of the metacarpal bone that connects with the wrist), and a head (the other end of the metacarpal bone that connects to the finger bone). Each of these five metacarpal bones articulates proximally with the wrist bone and distally with the digital bones. They are numbered from the thumb, the first metacarpal bone, to the little finger, the fifth metacarpal bone. The shafts of the metacarpal bones show concavities in the palmar aspect for the accommodation of the palm muscles, such as the palmar interossei and dorsal muscles.

What Are the Causes of Metacarpal Bone Fractures?

More often, metacarpal bone fractures are caused by a direct impact injury when the hand hits something with greater force or when something hits the hand. They are caused more frequently in contact sports. Here are a few common causes of metacarpal bone fractures:

• Almost 50 % of the cases occur during sports activities, a common cause among young athletes.

• In middle-aged patients, metacarpal bone fractures commonly occur during work-related injuries.

• In elderly patients, the fracture occurs mostly due to a fall.

Depending on the pattern and shape of the break line, fractures are divided as:

• Transverse fracture.

• Spiral fracture.

• Oblique fracture.

• Segmental fracture.

A direct blow over the dorsal part of the hands often causes a transverse fracture. At the same time, an axial and bending force causes oblique and spiral fractures.

What Is Boxer’s and Bennet’s Fracture?

• Boxer’s fracture is a fracture in the neck of the fifth metacarpal bone (the one which connects the wrist bone to the little finger). It is named the boxer's fracture because of its classic mechanism of injury, which occurs when a greater force is applied to a clenched fist. This fracture accounts for ten percent of all hand fractures.

• Bennets’ fracture is a fracture that occurs at the base of the first metacarpal bone (the one which connects the wrist bone to the thumb). This fracture often occurs when an axial force is applied over a bent thumb finger, or it might be associated with other metacarpal fractures.

How Common Are Metacarpal Fractures?

Metacarpal fractures are a common type of fracture, accounting for 40 % of all hand fractures. They typically occur in patients between 10 to 40 years old. They occur as an isolated fracture, along with other metacarpal fractures, or in association with other bone injuries.

What Are the Signs and Symptoms of Metacarpal Fractures?

The signs and symptoms of metacarpal fracture follow a high-impact injury to the hand.

• Hand swelling or deformity.

• Presence of significant bruising.

• Tenderness over the injured area.

• Presence of limitation of hand movements.

• Presence of severe pain.

• A significant lump or malignment might be seen.

• Severe pain when trying to make a fist.

How Is the Patient Evaluated for Metacarpal Fractures?

• The primary evaluation conducted by the healthcare provider will be thorough history taking especially when there is a presence of significant hand swelling. The healthcare provider will ask questions about the current working status, the patient's athletic participation, history of any prior injury, and history of previous surgeries.

• The healthcare provider will do a thorough physical examination of the hand. The doctor will perform a rotational assessment if there is any suspicion of rotational deformity.

• Radiographic investigations are performed to diagnose the condition, such as the standard radiographs of the hand in the anteroposterior, oblique, and lateral views.

• A computed tomography scan (CT) may be used in assessing any intra-articular displacement at the base of the metacarpal fracture.

What Are the Treatment Modalities for Metacarpal Fracture?

Treatment for a metacarpal fracture depends on the severity of the injury and the type of fracture. The ultimate goal of the treatment is to restore the functions and anatomy of the bone.

• Applying ice to the fractured area and elevation of the injured hand is recommended in the initial stages.

• Painkillers are prescribed for short-term relief of pain.

• If the fracture is simple, closed, and non-displaced, they are treated with extended immobilization made with the help of splints or cast for four to eight weeks, depending on the severity of the condition. These patients require follow-up for at least two years.

• In patients with closed and displaced fractures, a closed reduction is performed by anesthetizing the injured bone. Sometimes this procedure is done under general anesthesia or by giving sedation to the patient. Closed reduction is followed by immobilization with splints.

• Some cases with metacarpal fractures require surgery. In displaced fractures, the surgeon will perform internal fixation, i.e., once the displaced fracture bones are realigned in their correct position, the surgeon includes screws and plates to stabilize the fractured bones. Follow-ups are required, and the screws or plates are removed once the bone is healed.

• The recovery time depends on the type of fracture and the treatment modality performed, but the fractured bone will completely regain its strength in around six weeks.

• Once the healing of the bone is achieved, patients are recommended for rehabilitation with physical therapy.

Conclusion:

Metacarpal bone fractures are common hand fractures due to direct impact injury over the hand. They commonly occur in patients of age between ten to thirty years. The frequent symptoms include pain, swelling, tenderness, and hand deformity. They are mostly diagnosed through hand X-rays. Most patients with metacarpal fractures require only non-surgical treatment options. Full strength and range of motion are achieved through rehabilitation in physical therapy.