What Is a Scaphoid Fracture?

A scaphoid fracture is a break in the scaphoid bone, a kidney bean-shaped bone that sits below the thumb and is part of the wrist joint. Scaphoid fractures are most commonly caused by a fall onto an outstretched hand. This type of break often causes pain and swelling on the thumb side of the wrist.

Cast immobilization is typically recommended for this type of fracture, but this can vary. Since scaphoid fractures can take a long time to heal, and may not do so completely, surgery may sometimes be required.

Causes and Types of Scaphoid Fracture

Scaphoid fractures are most commonly caused by a fall onto an outstretched hand. The force of the injury leads to damage to the scaphoid bone.

Scaphoid fractures are generally classified as either displaced or nondisplaced:

• A nondisplaced scaphoid fracture means that the bone has not shifted at all out of position, and the fracture may not even be visible on an X-ray image.
• A displaced fracture of the scaphoid occurs when the bones have shifted out of position. These types of fractures often require more invasive treatment, because the healing of a displaced scaphoid fracture is much less predictable.
  

Scaphoid Fracture Symptoms

The signs of a scaphoid fracture include:

• Pain on the thumb side of the wrist
• Swelling and bruising on the thumb side of the wrist
• Difficulty gripping objects

Many patients are erroneously diagnosed with a wrist sprain when in actuality they have a broken scaphoid bone.

Diagnosis

The diagnosis is difficult because X-rays taken right after the injury may show no abnormality if the bone is not out of position. A scaphoid fracture that is not displaced may only show up on X-ray after healing has begun, which can be one to two weeks after the injury.

Because of this, it is not uncommon to treat a wrist injury with immobilization (as though it were a scaphoid fracture) for a week or two and then repeat X-rays to see if the bone is broken. An MRI can also be used to diagnose this injury without having to wait to repeat an X-ray.

Treatment

When treating a scaphoid fracture, your healthcare provider will set specific goals. In addition to trying to regain mobility, treatment should relieve pain and help prevent the development of arthritis in your joint.

Usually, surgery is necessary to fully heal your wrist, but in some cases, a scaphoid fracture can be treated with just a brace.

Cast Immobilization

As long as the scaphoid fracture is not displaced (out of position), cast immobilization is a very reasonable treatment. The cast must extend over your thumb to limit the mobility of your thumb. How high up to extend the cast (above or below the elbow) depends on healthcare provider preference. Your healthcare provider will continue to monitor the wrist both by examination and X-ray assessment to ensure there is healing of the bone. Healing of a scaphoid fracture often takes 10 to 12 weeks.

Surgery

If the scaphoid fracture is displaced, the risk of nonunion is higher, and your healthcare provider will recommend surgery to reposition the bones and hold them solidly in proper alignment. The surgery typically involves using a single screw to hold the bone together in the proper position. 

There is some controversy about using surgery as an initial treatment of a fracture that is not out of position. The advantage is that there is less of a risk of nonunion and the time for immobilization can be dramatically reduced.

The disadvantage is that surgery always has risks, and while the complication rate of scaphoid fracture surgery is small, there is a possibility of complications, including injury to cartilage or tendons around the scaphoid and infection.

Many athletes or manual laborers choose to have surgery to allow a faster recovery.

Recovery

After surgery, you will also need to wear a cast. It can then take up to six months for a fracture to heal, which is longer than other types of fractures.

As you heal, you'll need to restrict your activity. This may include changes such as:

• Avoiding lifting more than one pound
• Not throwing with the arm that was fractured
• Not playing sports that risk full contact or falling on your wrist
• Not Climbing ladders or trees
• Avoiding the use of heavy or vibrating machinery

In addition, you should not smoke during recovery since it can slow down the healing process.

When a Fracture Doesn't Heal

A scaphoid fracture may heal slowly (delayed union) or not at all (nonunion). This is especially likely if you are misdiagnosed or if treatment is delayed, and it is largely due to how blood is supplied to the bone.

The scaphoid bone has a retrograde blood supply, meaning that blood flow comes from a small vessel that enters the most distant part of the bone and flows back through it.

This unusual flow of blood presents a problem when there's a fracture: Because of how tenuous the blood supply is, a bone break can easily sever it. This stops the delivery of necessary oxygen and nutrients to the bone cells, impeding healing.

These injuries can be complex. Long-term pain and tissue death (avascular necrosis) can occur.

Lengthy treatment is often required to get the bone to heal. A bone graft is often used to promote healing at the fracture site. Without proper treatment, wrist arthritis is likely to develop later in life.

A Word From Verywell

Scaphoid fractures are common wrist injuries, and the treatment may depend on a number of factors. Cast immobilization avoids surgical treatment and risks of infection and cartilage injury, but may require prolonged immobilization and lead to stiffness of the joint. Surgical treatment has risks associated with it, but may provide more predictable healing. Other factors, such as patient age, activity level, and fracture location and type, may all influence the recommended treatment as well.