What is it?
The wrist contains 8 small bones that form a joint with the bones in the forearm. The scaphoid is one of these bones and is found at the thumb side of the wrist. It is the most commonly fractured bone in the hand.
What causes it?
Fractures of the scaphoid normally result from a fall onto the outstretched hand. Although the fracture can occur at any age they tend to occur most frequently between the ages of 20-30 years. It is unusual for the scaphoid to fracture in very young children.
What are the signs and symptoms?
Pain over the wrist, particularly over the thumb side is a common early feature. The wrist may also be bruised and swollen. Movement of the wrist, in particular bending the wrist back is likely to be painful. Pain in the anatomical snuffbox (the hollow area at the base of the thumb that becomes obvious when pulling the thumb back) is a characteristic feature of scaphoid fractures.
How is it diagnosed?
Diagnosing a scaphoid fracture can often be difficult in the early stages. A thorough history and examination should raise the suspicion of a scaphoid fracture. A series of X-ray images is requested but may not show the fracture immediately. The fracture may become a bit more obvious a couple of weeks down the line when the bone at the fracture ends absorbs, making the fracture easier to see on the X-ray images. In some cases an MRI scan is needed to confirm the diagnosis as the X-rays alone fail to identify the fracture.
How is it treated?
The treatment is dependent upon a number of different factors:
Age of injury: Earlier treatment generally results in better outcomes. When fractures have been neglected and have failed to heal an operation becomes more likely and the result is not as reliable.
How much the fracture has moved from it's normal position: Scaphoid fractures that do not move a great deal from the original position (undisplayed) can normally be treated without surgery and will require a platter cast for 6-10 weeks. Fractures in which the fragments have moved apart (displaced) will in most cases require surgery.
Part of scaphoid that is fractured: The vast majority of scaphoid fractures occur through the central part of the bone (waist). These will normally heal without surgery in over 80% of cases if the fragments have not displaced. Fractures that occur closest to the wrist joint (proximal pole) tend to be the least likely to heal and those that occur furthest from the wrist joint are the most likely to heal. The difference in healing is related to the blood supply of the bone. The area with the best blood supply is furthest away from the wrist joint and therefore heals will. These fractures heal reasonably well without surgery. The fractures closest to the wrist joint, where the blood supply is the poorest, normally require surgery to allow the bone the best chance to heal.
Other associated Injuries: Fractures of the scaphoid can often occur with a combination of other bone or ligament injuries. In a situation where there a multiple injuries an operation may become necessary.
What does the operation involve?
The nature of the operation will depend on the fracture type and the delay between the injury and the operation. The operation will be performed with you asleep and is most cases is performed as a day case procedure. Most scaphoid fractures will be fixed with a screw being passed through the centre of the scaphoid and this then remains embedded inside the bone. In cases where the operation occurs within days after the injury, the operation may be carried out through a very small incision (percutaneous). In delayed cases a bigger 4-5cm incision may be required to align the bone fragments and to place a bone graft to fill the space between the bone ends. The graft is normally taken from the Radius bone in the wrist through the same incision. The graft may be taken as a piece of bone alone (non-vascularised graft) or piece of bone with it's blood supply still attached (vascularised bone graft).
Irrespective of the nature of the operation, you are likely to spend some time in a cast or splint. The period for which this is used depends on the operation type. In most cases the period will be a minimum of 4 weeks and this is in some cases followed by a period in a custom-made splint that can be removed to perform exercises.
Return to work
This again is dependent on the operation and the nature of your work. This will be discussed with you during your consultation.
Driving is only really possible once you are out of cast and even then it can take a couple of weeks out of cast before you can drive comfortably.
Like with any surgery there are a number of small risks associated with this operation.
Infection (1%) is a risk with all surgery. In the majority of cases these are infections around the wound and can be treated with a course of antibiotics. The more unusual deep-seated infections however can require admission to hospital and surgery to clean the wound out if necessary.
Swelling and Stiffness can remain for many months following surgery. It is important to elevate the limb and keep all joints that are not immobilised with a splint, active.
Fracture not healing (non-union) although most fractures will go on to heal the overall failure of healing in these features is between 10-15%. This is higher for fractures of the proximal pole.
Scar Sensitivity is often a problem with surgery in the hand, particularly the palm. This is often self-limiting and daily massage of the scar can shorten the duration of the symptoms. The sensitivity does settle is all cases with time.
Nerve Injury is a potential but very rare risk with this surgery. Often the nerves at greatest risk are the tiny nerves supplying skin in the area of the wound and cutting through these may result in an area of numbness that is not often troublesome.
Complex Regional Pain Syndrome is an extremely rare (1%) complication that can follow any injury or surgery to a limb. In this situation the nerves in the arm over-react to the point where the hand becomes very painful, swollen and sensitive. This condition does improve with time but can be problematic for many months (see section on Complex Regional Pain Syndrome).