Anatomy of the Thumb
The thumb (also called the first finger) is made up of two small bones called phalanges that project off of the first metacarpal bone of the hand. The proximal phalanx extends from the base of the thumb to the knuckle. The distal phalanx extends from the knuckle to the tip of the thumb.
What are thumb fractures?
The thumb can be fractured during falls, sports injuries, and many other forms of hard impact or abnormal twisting motion. Thumb fractures are a serious, but temporary problem that can affect the ability to grasp objects.
Any of the bones of the thumb can be fractured, but thumb fractures most commonly occur at the base of the metacarpal bone. In children, thumb fractures may involve the physis (growth plate) if they are close to the base of the metacarpal bone.
Thumb fractures that involve the joint between the metacarpal and the bones of the wrist are called intra-articular. Intra-articular fractures are associated with worse outcomes, but pediatric fractures can usually be corrected with proper treatment.
A few common examples of intra-articular thumb fractures include:
- Bennet fracture: a fracture in the base of the metacarpal that may involve the growth plate. Thus, it is important to receive proper treatment to avoid long-term effects.
- Rolando fracture: a fracture in the base of the metacarpal, but does not involve the growth plate.
Extra-articular fractures do not involve the joint and are associated with better outcomes after treatment.
Signs and Symptoms:
Most children will experience immediate, intense pain upon fracturing the thumb.
Other symptoms may include:
- Swelling and bruising
- Visible deformity (crooked thumb)
- Inability to properly move the thumb or grasp objects
- Weakness and numbness in the thumb
Diagnosis:
If a thumb fracture is suspected based on the symptoms above, it is important to see a doctor as soon as possible for physical examination and imaging tests (X-ray). If treatment is delayed, it may be more difficult to fix the bone alignment and treat the broken thumb.
During physical exam, the doctor will carefully inspect the thumb, and test for nerve and blood vessel involvement. Typically, X-ray imaging is sufficient to confirm the diagnosis of a thumb fracture.
If the fracture is severe or complicated, it may be necessary to use other imaging techniques such as ultrasound, MRI, or CT scans.
Treatment:
Treatment plans for thumb fractures vary based on the type, severity, and location of the fracture. A Campbell Clinic orthopedic physician will address the findings from physical exam and imaging studies (X-ray) to determine the best treatment plan for the fractured thumb.
Most children are able to recover from thumb fractures without surgery due to the ability of the bone to remodel.
Non-Surgical Treatment:
If the child is less than 12 years old, the bones are lined up relatively well, and there are no major complications with the fracture, treatment usually consists of the following:
- Specialized thumb cast (spica cast) for 3-4 weeks
- Pain management using over the counter medication
- Range of motion exercises as directed by the orthopedic physician
If the fractured bones are not lined up properly, the orthopedic physician may need to perform a closed reduction procedure in which the bones are pulled back into place without cutting skin.
Surgical Treatment:
In more complicated or severe fractures, surgery may be necessary to correct the bone alignment and clean out the affected area.
During surgery, the physician may use pins, screws, wires, or plates to correct the position of the bone and keep the bone from shifting while it heals. These pieces of hardware are typically removed after about a month of healing.
After surgery, a cast or splint should be worn for 3-6 weeks to protect the thumb while it heals.
Outlook (Prognosis):
With proper treatment and strengthening exercises, most thumb fractures heal without causing any long-term problems in children and teens. Most pediatric thumb fractures fully heal by 6 weeks.
It is typically recommended to schedule follow up appointments with an orthopedic physician every few weeks until the thumb has fully healed, especially in the case of more severe fracture.