What is it?
The scaphoid bone is the most common of all the small bones of the wrist to be fractured. Fractures are usually caused by falls onto the outstretched hand.
Most fractures (around 90%) will heal if immobilized in a Plaster for a sufficient period (6-12 weeks on average). This is lower if the fracture is displaced. However, some fractures do not unite (heal). Generally, the nearer the bottom of the scaphoid (proximal pole), the poorer the blood supply and the less likely it is to heal. Some proximal pole fractures only have a 20-30% union rate. If you are a smoker, then the risk of non-union is much higher due to the negative affect of smoking on the blood supply to the scaphoid.
Although some patients with a scaphoid non-union have few symptoms, most experience some discomfort and stiffness. If left untreated, the natural history is the almost certain development of wrist osteoarthritis causing increasing symptoms and disability of pain and stiffness.
What can be done?
First confirmation will be needed that the scaphoid has not heald. This will be done with X-rays and usually a CT and/or a MRI scan. These scans give a better idea of the situation in the scaphoid bone with regards to the position, blood supply, and whether any healing has taken place or not.
The only real treatment is surgery. This will usually be done under a general anaesthetic and may require a one night stay in hospital.You will have a scar either over the front or back of the wrist, depending where in the scaphoid the non-union is. You may well have a scar over the pelvis for the harvesting of bone graft. This will all be discussed with you before surgery.
The aim of the treatment of the non-united scaphoid is to heal the bone and restore its shape. Surgery therefore involves (i) freshening of boneends with removal of scar tissue and bone fragments (ii) correction of any displacement and collapse, (iii) insertion of a bone graft from the hip or wrist, to maintain the correction and (iv) stabilisation of the bone and graft with a screw. When the cause of non-union is poor blood supply, a vascularised bone graft (connected to its blood supply) can be transferred from the radius. This may give a slightly higher chance of union occuring, but this is debatable.
After the operation, your hand will be placed in a bulky dressing, which includes a plaster to protect the operation. Hand elevation is important to prevent swelling and stiffness of the fingers. Movement of the hand and thumb-tip should be continued and you should perform normal light activities after the operation. If a graft has been taken from the pelvis, this can be quite uncomfortable for a period of time ( a day or two).
Six weeks after the operation your wrist will be X-Rayed. If all is well, you can begin to take off your splint during the day for initially light use. However, it is worth wearing it for protection or at night for at least another six weeks after the operation. Physiotherapy will now be started and aimed at recovering wrist movements.
If all goes well, your fracture should unite over a 6-8 week period but it can often be 3 months before you can resume heavy activities. The fracture can, however, take longer to heal and your progress will be judged by examination and X-Ray. You may need to be patient. Also the above times are only a rough estimate.
There is about a 20 – 30 % chance of the fracture failing again to unite. This is significantly higher if you are a smoker.
Surgery attempts to prevent the development of arthritis. However, damage may have occurred during the time the fracture was ununited. Therefore it cannot be guaranteed that arthritis will not occur later even if the operation succeeds in healing the fracture.
You will have a scar on the wrist, which will be somewhat firm to touch and tender for 6-8 weeks. You can ease the tenderness by massaging the area firmly with moisturizing cream.
This can occur after any operation and would be treated by antibiotics.
You are likely to lose some movement at the wrist if you have not already done so. About 5% (1 in 20) of people are sensitive to hand surgery and their hand may become swollen, painful and stiff after any operation (Complex Regional Pain Syndrome). This problem cannot be predicted but will be watched for afterwards and treated with physiotherapy.
A small nerve running in the region can occasionally be damaged during the surgery and either cause numbness in the palm or form a painful spot in the scar (neuroma). The latter complication may require a further operation to correct it.