What is a Scaphoid Fracture?
A scaphoid fracture most commonly results from a fall on an outstretched hand. The scaphoid is a small bone located on the thumb side of your wrist. The scaphoid is unique in that it spans the two rows of bones that make up your wrist. Because of its position, it is the most commonly broken bone in the wrist. Because symptoms can be minimal, scaphoid fractures are frequently mistaken as sprained wrists. The patient frequently overlooks the fracture because it feels like a sprain. There is often only a little swelling and a variable amount of pain may be present. Usually, the swelling will go away in a few days. Unlike the forearm, hand, and finger bones, fractures of the scaphoid almost never show any obvious deformity of the wrist. These factors can make it common for the diagnosis to be delayed for weeks, months or occasionally even years after the initial injury because the patient or his doctor thinks it is just a common wrist sprain. Scaphoid fractures require casting or surgery.
Who gets this type of fracture?
In adolescents and young adults, fracture of this bone is the most common fracture around the wrist. Men are much more likely to fracture this bone than women. Although the bone is small, it takes a lot to break it. Twice as much force is required to break the scaphoid bone as to break one of the bigger forearm bones. Because of this, most patients who have broken their scaphoid have done it while participating in sports, such as football, basketball, riding a motorcycle or in an automobile accident. Usually the patient falls on the outstretched hand and hyperextends the wrist joint.
What are the Symptoms of a Scaphoid Fracture?
A scaphoid fracture causes tenderness directly over the bone. The pain may increase when you move your thumb or grip things. Your initial pain may decrease over days or weeks. Scaphoid fractures usually do not cause bruising or significant swelling, which is the reason they are often mistaken for a sprained wrist.
When a scaphoid fracture is recognized on the first X-ray, treatment begins immediately. But patients often assume that the injury is just a sprain, and they wait for it to heal on its own. In some cases, the wrist gets better. In many cases the bone fails to heal. The scaphoid fracture then develops into what surgeons call a nonunion.
A nonunion can occur in two ways. In a simple nonunion, the two pieces of bone fail to heal together. The second type of nonunion is much more serious. The lower half of the fractured bone loses its blood supply and actually dies. This condition is called avascular necrosis (Avascular means no blood supply, and necrosis means dead.)
The scaphoid bone is at risk for avascular necrosis. Only one small artery enters the bone, at the end that is closest to the thumb. If the fracture tears the artery, the blood supply is lost. Avascular necrosis becomes easy to see on X-rays several months after the injury.
Symptoms of a nonunion of the scaphoid bone are more subtle. You may have pain when you use your wrist. However, the pain may be very minimal. It is fairly common for doctors to see a nonunion of the scaphoid bone on X-rays, but the patient can’t remember an injury. Still, the most common symptom of a nonunion is a gradual increase in pain. Over several years the nonunion can lead to degenerative arthritis in the wrist joint.
How is a Scaphoid Fracture Diagnosed?
Your doctor can diagnose a scaphoid fracture by examining your wrist and taking X-rays. Sometimes scaphoid fractures do not show up on initial X-rays. Doctors should assume that any patient who has fallen on an outstretched hand and has swelling or tenderness on the thumb side of the wrist has a scaphoid fracture. You should assume this until tests prove otherwise. X-rays taken immediately after the injury may not show a fracture. Still, most surgeons will put a cast on the wrist and get another X-ray in 10 days. This gives the edges of the fractured bone time to heal, and may prevent nonunion. By waiting 10 days, the fracture is easier to see on an X-ray.
If it is still not clear whether or not you have a fracture, your doctor may order other imaging tests. You may have a bone scan done. A bone scan involves injecting tracers into your blood stream. The tracers then show up on special X-rays of your wrist. The tracers build up in areas of extra stress to bone tissue, such as a fracture.
How is a Scaphoid Fracture Treated?
Treatment depends on the location, fracture type, and fracture location in the bone. Fractures located near the thumb (distal pole) heal well with casting. Fractures in areas with a poor blood supply and displaced fractures generally require surgery.
If the fracture is identified immediately and is in good alignment, you will probably wear a cast for nine to 12 weeks. The cast will cover your forearm, wrist, and thumb. This is necessary to hold the scaphoid bone very still while it heals. Your doctor will take X-rays at least once a month to check the progress of the healing. Once your doctor is sure the fracture has healed, the cast will be removed. Even with this type of treatment, there is still a risk that the fracture may not heal well and will become a nonunion.
A fracture that doesn’t heal within several months is considered a nonunion. If the injury is fairly recent, your doctor might recommend more time in the cast. He or she might also prescribe an electrical stimulator. The electrical stimulator is a device that sends a small electrical current to your scaphoid bone. You wear it like a large bracelet for 10 to 12 hours a day. Electrical current has been shown to help the bones heal.
Surgery for scaphoid fractures can be done through a tiny incision when the bone fragments do not need to be reduced (manipulated). Otherwise, a relatively small incision at the base of the thumb is needed. The surgical approach is determined by the fracture location in the bone. Headless screws, of which there are several types, are used to hold the scaphoid bone in position while it heals. A cast or splint is worn for some time following surgery.
- Screw Fixation – Some surgeons report good results doing surgery right away when a patient has had a recent, non-displaced scaphoid fracture. Studies have shown that this method can help people get back to activity faster than wearing a cast for up to 12 weeks. The procedure involves inserting a screw through the scaphoid. The screw holds the scaphoid firmly until it heals.
- Scaphoid Debridement – In cases where a nonunion has occurred despite wearing a cast and using an electrical stimulator, surgery will likely be suggested. An incision is made in the wrist directly over the scaphoid bone. The surgeon finds the old fracture line on the scaphoid bone. All the scar tissue between the two halves of the bone must be removed (debrided). This creates a fresh bone surface to allow healing to begin again. In some cases, damaged bone tissue from the scaphoid is also removed.
- Bone Graft Method – Your surgeon may use a bone graft. A bone graft involves taking bone tissue from another spot in your wrist and inserting it into the fracture. A bone graft can stimulate healing on the surface of the bones. The bone graft is usually taken through a second small incision just above the wrist.
Sometimes the bones still do not heal as planned. Surgeons call a fused bone that fails to heal a pseudarthrosis. If the nonunion continues to cause pain, you may need a second operation. Your surgeon will probably add more bone graft and check that the pins or screws are holding the bones together.
Depending on the type of surgery you have, you may be placed in a splint for up to 12 weeks after surgery. Your surgeon will X-ray the wrist several times after surgery to make sure that the bones are healing properly. Once the two halves of the scaphoid bone have healed, you can safely begin a rehabilitation program.
You may need physical or occupational therapy sessions for six to eight weeks after surgery. The first few treatments will focus on controlling the pain and swelling. You will work into doing exercises to help strengthen and stabilize the muscles around the wrist joint. Other exercises are used to improve fine motor control and dexterity of your hand. You’ll be given tips on ways to do your activities while avoiding extra strain on the wrist joint.