There are many bones in and around the wrist, so the term "broken wrist" can be confusing or vague.
By far, the most common type of broken wrist is a distal radius fracture, which is a break near the wrist end of the long radius bone in the forearm. This fracture often occurs as the result of a fall onto an outstretched hand.
However, there are several other possible types of wrist fractures that can occur. This article will discuss the second most common type of wrist fracture, a scaphoid fracture, as well as others.
Scaphoid fracture causes and symptoms
The scaphoid is one of eight small round bones that sit in two rows in the wrist. This cashew-shaped bone is positioned near the base of the thumb, just above the long radius bone of the forearm.
As with distal radius fractures, scaphoid fractures almost always are the result of a fall onto an outstretched hand. They can also occur as the result of sports activities or car accidents.
The population most at risk for a scaphoid fracture is young, active men. This group is the least likely to suffer a distal radius fracture—the more common injury—after a fall. Some experts believe this may explain their vulnerability to scaphoid fractures.
The symptom of a scaphoid fracture are sometimes hard to discern and easily mistaken for other injuries, such as a wrist sprain.
Scaphoid fracture symptoms include:
- Pain on the thumb side of the wrist that is dull or deep
- Pain or swelling located on the thumb's "snuffbox," which is a small depression at the base of the thumb that can be seen when the thumb is flexed away from the hand
- Mild pain that gets worse when pinching or gripping an object
There is rarely bruising and no deformity when a scaphoid fracture occurs, which is why it may be mistaken for a sprain.
Diagnosing and treating scaphoid fractures of the wrist
Scaphoid fractures that are not diagnosed and treated are in danger of developing two serious complications:
- Nonunion: the bone fragments heal improperly or incompletely
- Avascular necrosis: the fracture causes blood supply to be cut off to part or all of the bone, causing the bone tissue to die
Both of these complications can lead to bone collapse and arthritis. This is why it's essential for patients who experience ongoing pain after a fall to seek medical treatment.
Medical imaging is the only definitive way for physicians to diagnose a scaphoid fracture. Even then, it can be difficult to see a scaphoid fracture on an X-ray. Multiple X-ray images may be needed from different vantage points. Frequently, a more detailed test such as CT or MRI may be used to obtain a clearer image of the fracture.
The need for surgery depends on the fracture
Once a scaphoid fracture has been diagnosed, it can be treated through either nonsurgical or surgical options—or sometimes both.
If the fracture is non-displaced (the bones are still in position), physicians may recommend 6 weeks of immobilization in a cast, accompanied by imaging check-ups to confirm the fracture is healing correctly. Despite the smallness of the bone, the cast may be fairly extensive, because the scaphoid bone is involved with almost all movement of the hand and wrist.
If the scaphoid bone is not healing properly (non-union), a bone stimulator—a device that delivers low-intensity ultrasonic or pulsed electromagnetic waves—may be used to promote bone growth.
For a fracture that poses risk for non-union or is displaced, surgery is the best recourse for treatment. Depending on the nature of the fracture, the surgeon will choose how to approach the fracture (front or back of the wrist) and how extensive the incisions need to be.
Once the fracture is reached, the surgeon will manipulate the bone back into proper position and then stabilize it with fixation tools such as wires or a screw. The surgeon may also recommend a bone graft if there is potential that the bone will not regrow well.
Recovering from a scaphoid fracture
Because of the scaphoid bone's poor blood supply, scaphoid fractures can take a longer time to heal than other fractures. With or without surgery, patients may need to wear a cast or splint for up to 6 months.
Even while the wrist is immobile, finger exercises are important in order to maintain circulation and flexibility. Once the cast or splint is removed, patients can work with a physical therapist to restore as much strength and flexibility as possible. For some people, the nature of the fracture may mean they are not able to fully restore function of the wrist.
If a scaphoid fracture is diagnosed and treated early, the chances of it healing properly are much greater. Unfortunately, a delay of weeks or months in being diagnosed and treated increases the chances for a non-union and/or arthritis. For this reason, receiving prompt medical care when the fracture is suspected is essential.