Scaphoid Fracture - Symptoms, Test & Treatment
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 this injury can be overlooked and thought just to be a common wrist sprain. Scaphoid fractures require casting or surgery.
Causes & Symptoms
A scaphoid fracture most commonly results from a fall on an outstretched hand. 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 recognised 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 non-union.
A non-union can occur in two ways. In a simple non-union, the two pieces of bone fail to heal together. The second type of non-union 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 of 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 non-union of the scaphoid bone may be more subtle. You may have pain when you use your wrist. However, the pain may be very minimal. It is not unusual for doctors to see a non-union of the scaphoid bone on x-rays, but the patient can’t remember an injury. Still, the most common symptom of a non-union is a gradual increase in pain. Over several years the non-union can lead to degenerative arthritis in the wrist joint.
Your doctor can diagnose a scaphoid fracture by examining your wrist and taking specific x-rays. Sometimes scaphoid fractures do not show up on initial x-rays, particularly if specific dedicated views are not sought. 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 until tests prove otherwise. X-rays taken immediately after the injury may still however not show a fracture. If there remains a high index of suspicion, the wrist should be immobilised in a splint and further imaging should be achieved. This potentially could simply be by repeating dedicated x-ray views of the scaphoid at 10-14 days after the injury or performing an MRI scan.
Repeating plain x-rays after 10-14 days often will reveal a fracture which was not initially apparent as the fracture gap widens initially as part of the normal healing process. An MRI scan is extremely sensitive and will identify a fracture, even if it still is not visible on x-ray at two weeks. An MRI however also has the advantage of identifying other injuries, for example significant ligament injuries which may present in a similar fashion.
As part of treatment, CT scans also have a role. These can be used to assess the success of union but also can assess the 3D anatomy of the scaphoid bone, particularly when the bone has failed to unite. The shape of the bone ultimately is also important in allowing the complex mechanics of the wrist to function well.
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 twelve 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 non-union.
A fracture that doesn’t heal within several months is considered a non-union. 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 and often can be inserted through a very small scar.
Scaphoid Debridement – In cases where a non-union has occurred despite appropriate treatment, surgery will likely be suggested. An incision is made in the wrist directly over the scaphoid bone. Depending on the exact location of the non-union the scar may need to be on the palmar side of the wrist or on the back of the wrist. The surgeon finds the old fracture line on the scaphoid bone and 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 and stability and compression of the two fragments is achieved with a screw.
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. Sometimes it is necessary to take the bone graft from the brim of your pelvic bone if it is necessary to alter the shape of the scaphoid in the presence of a longstanding non-union.
Sometimes the bones still do not heal as planned. Surgeons call a fused bone that fails to heal a pseudarthrosis. If the non-union 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 hand therapy 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 stabilise 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.