Your scaphoid bone is one of your carpal bones in your hand around the area of your wrist. It is the most common carpal bone to fracture (break). A scaphoid fracture is usually caused by a fall on to an outstretched hand. Symptoms can include pain and swelling around your wrist. Diagnosis of a scaphoid fracture can sometimes be difficult as not all show up on X-rays. Treatment is usually with a cast worn on your arm up to your elbow for 8 to 12 weeks. Sometimes surgery is advised. Correct diagnosis and prompt treatment of a scaphoid fracture can help to reduce complications.
There are two bones in your forearm (the part of your arm between your elbow and your wrist). These are called your radius and your ulna.
Your radius is on the thumb side of your wrist and your ulna on the little finger side.
In your hand, you have eight small bones known as your carpal bones. They are arranged in two rows one on top of the other.
The proximal row is the row that is closest to your body. In the proximal row are your scaphoid, lunate, triquetrum and pisiform bones. The distal row is the row below this. In the distal row are your hamate, capitate, trapezoid and trapezium bones.
Your scaphoid bone is one of the largest of your carpal bones and is on the thumb side of your wrist. It looks a bit like a cashew nut and is roughly the same size. It links the two rows of carpal bones together and actually helps to stabilise them. Your scaphoid bone and your lunate bone articulate (connect) with your radius at your wrist joint.
A scaphoid fracture is when you break your scaphoid bone. It most commonly happens after a fall on to your outstretched hand. That is, when your palm is flat and stretched out and your wrist is bent backwards as you fall to the ground. Instinctively, you will usually put your hands out in this position for protection if you fall forwards.
Sometimes a direct blow to the palm of your hand can cause a scaphoid fracture. Occasionally, repeated 'stress' on the scaphoid bone can lead to a fracture. This can occur, for example, in gymnasts and shot putters.
Commonly you will just fracture your scaphoid bone but sometimes other bones around the wrist area may be broken at the same time.
Scaphoid fractures may be non-displaced (the fragments of the broken bone haven't moved out of position) or displaced (there is some movement of the bone fragments).
The scaphoid bone is the most commonly fractured carpal bone. This is because of its size and position in the two rows of carpal bones in your hand.
Usually, most people with a scaphoid fracture will remember a specific injury or fall. There will be pain around your wrist area after the injury. You may also have some bruising or swelling around your wrist on the affected side.
In some people, symptoms may be milder. Quite commonly, people with a scaphoid fracture just assume that they have sprained their wrist and they don't seek medical attention for some time afterwards. The fracture may only be diagnosed when they see a doctor some weeks later because of pain that is not settling or reduced movement around their wrist.
A doctor will usually suspect a scaphoid fracture by the mechanism of the injury that you have sustained - for example, a fall on to an outstretched hand. Also, when they examine your wrist and hand, there is a specific point where you are likely to be tender if you have a scaphoid fracture. This is known as the anatomical snuffbox. It is a depression in your skin on the back of your hand near to the base of your thumb. Movement of your wrist in certain directions may also be painful if you have fractured your scaphoid.
It can sometimes be quite difficult to diagnose a scaphoid fracture. However, it is important to recognise and treat a scaphoid fracture as soon as possible because the complication of nonunion (see below) is more likely if treatment is delayed.
Standard X-rays may not pick up all scaphoid fractures. This is because the scaphoid bone can 'hide' behind the other carpal bones on an X-ray. Special scaphoid view X-rays taken with your hand and wrist in a certain position may help to show up a scaphoid fracture. However, between 1 and 2 in 10 scaphoid fractures may not be seen on X-ray.
In some cases, a scaphoid fracture will not show up on an X-ray until around 10 to 14 days after the initial injury. At this time, the healing process will have started in the bone, which will help the fracture site to show up. So, if a scaphoid fracture is suspected but not confirmed on an initial X-ray, you will usually be treated as if you have a scaphoid fracture (see below) and a repeat X-ray may be suggested after 10 to 14 days.
Sometimes, at this time, it is still not clear whether you have had a scaphoid fracture. If this is the case, a CT or MRI scan may be suggested to look for the fracture. A radionuclide bone scan is occasionally used as an alternative but this is used less often these days as MRI and CT scans are more widely available.
There is currently some debate as to whether there is benefit of doing further investigations such as a CT or MRI scan earlier if a scaphoid fracture is suspected but has not shown up on the initial X-ray. Earlier investigations may also not always be available on the NHS. You will usually be followed up by an orthopaedic surgeon in the outpatient clinic if a scaphoid fracture is diagnosed or suspected. They will be able to advise whether and when further investigations are needed.
If a non-displaced scaphoid fracture is confirmed on X-ray or is suspected, it is usually treated by putting your arm in a cast (commonly referred to as a plaster cast but actually made of fibreglass or another similar synthetic material) up to your elbow. The cast is usually worn for 8 to 12 weeks until the scaphoid bone heals. In some cases, it may be needed for longer.
If a scaphoid fracture is displaced, surgery may be advised. A small screw or a special pin is inserted into the scaphoid bone to hold the bone fragments together in the correct position. This can often be done via a small cut in your skin.
Sometimes surgery may be an option for some groups of people even if a scaphoid fracture is non-displaced. The idea is that it avoids you having to wear a plaster cast for a long period of time. In some cases it may remove the need for wearing a plaster cast altogether. Some also argue that it allows normal movement of your wrist to return more quickly than if you had just been treated with a plaster cast. This means that you can return to your usual activities more quickly. For example, if you are an athlete, a musician, or if there is another reason why you have significant pressure to return to high level activity quickly, this treatment option may be a consideration. However, this does mean going through a surgical procedure that does carry some small risks.
A scaphoid fracture will usually heal well if it is recognised and treated early. However, occasionally, complications can occur after a scaphoid fracture. These can include the following.
Delayed union is when the scaphoid bone has not healed completely after four months of being treated in a plaster cast. Nonunion is when the the scaphoid fracture has not healed at all. In nonunion, the bony fragments are still completely separated. Delayed and nonunion may be more likely if treatment of a scaphoid fracture is delayed for some reason. So, this is the main reason why a scaphoid fracture needs to be recognised and treated promptly. However, the exact position of the fracture in the scaphoid bone, whether the fracture is displaced of not, and whether or not there is avascular necrosis (see below) can also affect the healing of a scaphoid fracture.
If delayed or nonunion occur, various treatments may be suggested, including wearing a cast for a longer period or surgery to help join the bone fragments together. Surgery may involve a bone graft to help with fracture healing. This is when bone tissue is taken from another area of bone in your wrist and inserted into the fracture site.
This is where the fragments of the scaphoid bone heal in an incorrect position - for example, at a slight angle. If this occurs, it may affect the movement of your wrist and lead to pain and problems gripping and holding objects. Malunion may be seen on an X-ray or scans of your scaphoid bone. Surgery is usually needed to correct this complication. The scaphoid bone is re-broken, aligned correctly and a bone graft is used to correct the deformity and encourage healing.
Most commonly, a fracture occurs at the narrowest part of the scaphoid (known as the waist). This is where the blood supply to the scaphoid bone enters. So, there is a risk that if you have a fracture in this area, it can sometimes interrupt the blood supply to part of your scaphoid bone, leaving part of the bone without a blood supply. This means that the scaphoid will not be able to heal properly and part of the scaphoid bone 'dies', collapses and breaks up. ('Avascular' refers to having no blood supply and 'necrosis' means death.) If it occurs, avascular necrosis can be seen on an X-ray of the scaphoid bone some months after the initial injury. However, avascular necrosis does not occur with all fractures around the waist of the scaphoid.
This can develop some time after a scaphoid fracture in some people. It is more likely if there have been complications of nonunion, malunion or avascular necrosis.