A metacarpus is a group of five bones of the hand that are located between the phalanges and the carpus. Even though the metacarpal bones are small, they are mainly classified as long bones since they have the structural characteristics of long bones; each metacarpal bone consists of a shaft, distal head, and a wide proximal base. The bases of the metacarpal bones are generally wide and they articulate with the bones of the distal carpal row by the carpometacarpal joints:
- First metacarpal – The first metacarpal articulates with the trapezium.
- Second metacarpal – The second metacarpal also articulates with the trapezium, alongside the trapezoid and capitate.
- Third metacarpal – The third metacarpal articulates with the capitate.
- Fourth / Fifth metacarpal – The last fourth and fifth metacarpal articulates with the hamate.
Overall, the bases of the metacarpal bones articulate with each other and the shafts of the metacarpal bones are elongated; each features a flat triangular area on the distal part of its dorsal surface, only proximal to the knuckles. The palmar surfaces show the longitudinal concavities intended for accommodating the muscles of the palm, such as the dorsal.
A Bennett’s fracture is generally defined as a sudden crack or break in the first carpometacarpal (CMC) joint at the base of the thumb. This is the point where the metacarpal bone of the thumb meets one of the eight carpal bones (trapezium) that form the wrist. The cartilage that covers it helps in the extensive movement of the thumb and maintains joint stability.
In most cases, Bennett’s fracture causes this ligament to get detached from the bones, leading to a dislocation of the CMC joint. If this condition is left untreated, the injury may result in loss of functionality, thumb weakness, and the development of osteoarthritis at the base of the thumb.
For the most part, our thumb is the most important digit of the hand. Because the thumb opposes the other four fingers, it is critical in grip strength. Without the thumb, humans have trouble picking up objects and holding items; an injury to the thumb can seriously hamper someone’s quality of life.
In another condition known as Rolando fracture, the hand sustains a direct blow while the thumb is flexed, such as in the shape of a fist. This comes in contrast to a hand being extended while someone falls, as is common in other injuries. If the thumb is curled inward in the shape of a fist while an impact occurs, it might lead to Bennett’s fracture.
Causes & Symptoms of Bennett’s Fracture
Bennett’s fracture can be caused by falls, sports injuries, and several other forms of hard impact or abnormal twisting motion. This type of fracture is quite serious, although a temporary problem that can affect the ability to grasp certain objects.
Any of the bones of the thumb can be fractured, however, thumb fractures most commonly occur at the base of the metacarpal bone. In children, these fractures may involve the physis (growth plate) if they are close to the base of the metacarpal bone. Other common causes and symptoms linked to Bennett’s fracture include:
- Pain – The pain will constantly worsen when you attempt to move your thumb, especially if you try to form a grip on an object.
- Loss of motion – A sudden loss of motion and ability in the thumb is common. It is less common for someone to experience a complete loss of motion in a fractured thumb, and this is typically an indication of a more severe fracture.
- Tingling / numbness sensation – This occurs as a result of the restricted blood flow to the thumb.
- Feeling of being pierced through – It may be apparent that your thumb is deformed as a result of a moderate to severe fracture. In severe cases of Bennett’s fracture, you may experience the end of the bone piercing the skin. This is also known as an open fracture.
- Swelling and bruising – Visible bruising around the base of the thumb will appear rapidly, almost instantly. This occurs because when a fracture of any sort occurs, the fractured fragments will bleed into the tissue; hence what forms the bump and bruising.
- Disability – In most extreme cases, you may completely lose the ability to use the affected thumb.
- Insufficient healing – This can lead to weaker bone structure and disfigurement.
If you believe you have broken your thumb, it is essential that you seek immediate medical attention. As with any kind of finger fracture, there is a possibility that you can lose the function of that finger.
Who gets Bennett’s Fracture?
Bennett’s fracture comes with many risk factors ranging from a direct blow from a sports event to traumatic events, such as a motorbike accident. Other risk factors linked to Bennett’s fracture include:
- Vehicle accident – People who experience vehicle trauma are most likely prone to fracturing a bone, including the metacarpal bones. Accidents from a motorbike may increase the chances of a rupture.
- Sports – Your first metacarpal bone can also fracture from a sports activity involving twisting repeatedly. Some sporting events include wrestling, basketball, skiing, hockey, and baseball.
- Age – Patients ages 50 and older are prone to dislocating and/or fracturing their fingers due to general wear and tear (degeneration).
How Does Bennett’s Fracture Affect You? How Serious is it?
If you leave your first metacarpal bone untreated, it can lead to malunion. Malunion (non-union) are both problems that occur when a broken bone does not heal correctly. In a malunion, a bone heals but isn’t in the correct position.
Malunion symptoms include constant pain after treatment. In severe cases, however, the condition can cause a deformity and may require surgery to repair or correct it.
Bennett’s fracture may also predispose the patient to arthritis and loss of motion within the affected joints. Unfortunately, even after the restoration of articular congruity, some patients develop post-traumatic arthritis to the injury sustained as a result of the initial trauma.
Other complications of Bennett’s fracture include:
- Stiffness of the thumb joint.
- Bones not healing or recovering in a bad position.
- Continued weakness in the thumb or hand.
- Ongoing pain in the thumb or hand.
Recommended Treatment & Rehabilitation for Bennett's Fracture
During a diagnosis of Bennett’s fracture, your doctor will begin by performing a detailed physical examination. He or she will begin to test the strength and range of motion of your hand and fingers. Because this fracture is unstable, there will be evidence of significant weakness in the thumb.
This will prompt your doctor to order further imaging tests. Usually, an X-ray is the only imaging exam used to help diagnose Bennett’s fracture. The X-ray will be taken from multiple angles to determine the location of the fracture.
In this injury, the thumb is broken in multiple spots, creating a T or Y shape in the thumb itself. When the thumb breaks into several pieces, the muscles surrounding the thumb are able to pull on the bone fragments without any opposition from the other side.
As a result, the muscles are able to pull the bone fragments out of position. Therefore, your doctor may also order other imaging modalities in order to look for other associated injuries.
Treatment for Bennett’s fracture may be performed conservatively with:
- Closed reduction
- Plaster casting
- Percutaneous Kirschner wire (K-wire)
- Internal fixation
The primary issue in closed reduction is to obtain and then maintain adequate fracture reduction to allow healing in an anatomical position. Certain minor complications of this type of surgical treatment are pain and grip weakness, however, longer-term complications include the development of osteoarthritis of the first carpometacarpal joint.
For this reason, these fractures should only be treated by specialist hand surgeons given the risk of future disability associated with inadequate reduction.
After a diagnosis and / or surgery has been done, physiotherapy may be further advised. A physiotherapist will work with you following Bennett’s fracture to help regain regular hand motion, strength, and function, and will provide education and training to help you prevent any future injuries.
Therefore, your therapist will examine the base of your thumb, and design a treatment plan specific to your condition and goals to improve its function and restore strength to your hand. Your treatment will likely include:
Pain management
Your physiotherapist will help you identify and avoid painful movements and show you how to correct abnormal postures to reduce stress on the hand. He or she will recommend resting the affected area short-term and applying ice to it which will result in alleviation.
Manual therapy
Your physiotherapist may use manual techniques, such as gentle joint movements, soft-tissue massage, and palm stretches to get your hand moving properly.
Range-of-motion exercises
You will learn exercises and stretches to reduce stiffness and help your wrist and hand to move properly.
Strengthening exercises
Your physiotherapist will determine which strengthening exercises are perfect for you, depending on your specific areas of weakness. Therefore, your therapist will design an individualized home-exercise program to meet your needs and goals.
Patient education
Depending on the activities you plan on continuing, your physiotherapist will teach you different ways to perform actions, while protecting your palm. For instance, keeping the palm of your hand in a neutral position to reduce excessive force while performing repetitive tasks, and taking frequent breaks are ways to decrease your chances of reinjury.
Below is a list of exercises that are helpful regarding treatment for Bennett’s fracture:
Thumb IP flexion
Place your forearm and hand on a table with your affected thumb pointing up. With your other hand, hold your thumb steady just below the joint nearest your thumbnail. Bend the tip of your thumb downward, then straighten it. Repeat this method 8-12 times.
Thumb MP flexion
Place your forearm and hand on a table with your affected thumb pointing up. With your other hand, hold the base of your thumb and palm steady. Bend your thumb downward where it meets your palm, then straighten it. Repeat this stretch 8-12 times.
Thumb opposition
With your affected hand, point your fingers and thumb straight up. Your wrist should be relaxed, following the line of your fingers and thumb. Touch your affected thumb to each finger, one finger at a time. This will look like an “okay” sign, but try to keep your other fingers straight and pointing upward as much as you can. Repeat this method 8-12 times a day.
Thumb extension
First, place your hand flat on a table, palm down. Then, lift and lower your affected thumb off the table. Repeat this exercise 8-12 times a day.
Towel squeeze
Place a small towel roll on a table. With your palm facing down, grab the towel and squeeze it for about 6 seconds. Finally, slowly straighten your fingers to release the towel. Repeat this exercise 8-10 times a day.
Towel grab
Begin by folding a small towel in half, and laying it flat on a table. Next, put your hand flat on the towel, palm down. Grab the towel, and scrunch it toward you until your hand is in a fist. Slowly straighten your fingers to push the towel back so it is flat on the table. Repeat this exercise 8-12 times a day.
Alternative & Homeopathic Treatment for Bennett's Fracture
Usually, performing simple home remedies for mild symptoms linked to your fracture is enough to alleviate the pain.
Certain medications, such as over-the-counter pain relievers are a great source to cure pain, including non-steroidal anti-inflammatory drugs (NSAIDs). Here are other homeopathic treatments to help reduce Bennett’s fracture:
- Elevation – Keep your hand elevated above the level of your heart as much as possible. Elevation helps reduce swelling, therefore, the more your finger is swollen, the more time it will take to heal once it is elevated.
- Massage – Performing a self-massage directly to the base of your thumb can greatly reduce swelling while increasing blood circulation. You can also visit a professional massage therapist to help reduce the pain.
- Essential oils – Essential oils are known to contain anti-inflammatory properties when applied to the injured area.