Scaphoid Non-union
The scaphoid bone is one of the eight small bones of the wrist. It is the most commonly fractured wrist bone, classically occurring after falls onto an outstretched hand. The scaphoid bone has a very limited blood supply, especially the part of the scaphoid that is closest to the wrist joint itself (“the proximal pole”). Most fractures of the scaphoid will heal (unite) without problem following a period of immobilisation (6-12 weeks) in a splint or Plaster of Paris. Fractures that are displaced or are in the area of the proximal pole, have a higher chance of not healing, which is called a non-union. Smoking also significantly increases the chance of a scaphoid non-union occurring.
Patients will often complain of pain, particularly on gripping objects firmly, on the thumb side of the wrist. Loss of wrist movement and pain on activities such as push-ups are common. Some patients with a scaphoid non-union will have surprisingly few symptoms initially. The non-union does however change the complex biomechanics of normal wrist movement. This will almost inevitably lead to a particular pattern of arthritis developing in the wrist, which is called a SNAC wrist (scaphoid non-union advanced collapse). This causes increasing pain and stiffness.
Diagnosis:
Treatment options
Available treatment for wrist scaphoid non-union
In cases where there is no arthritis, the following treatments may be discussed. We would advise surgical intervention in such cases, in order to reduce the chances of developing arthritis in the future.
The aim of surgery is to realign the scaphoid, where necessary, and freshen up the bone ends to allow union to occur. A screw is placed down the middle of the scaphoid to hold the two bone fragments rigidly whilst healing occurs. A gap is often present between the bone ends, which is filled with bone graft. This bone graft can be either taken from the wrist or hip area in most cases. In cases where the blood supply to the scaphoid is felt to be very poor, a special type of bone graft which is still attached to a blood vessel can be harvested from the wrist. This is called a vascularised bone graft. This may give a slightly higher chance of the non-union healing, although the evidence for this is still debated.
Post-operative care
You will be seen in the outpatient department approximately two weeks following your operation. The wound will be checked and your dressing changed. Another splint or Plaster of Paris will be applied. The wrist will need to be protected until the scaphoid has healed.
At six weeks, an X-ray will be taken to see whether the bones have joined. A removable splint may be applied at this stage. Rehabilitation of the wrist will be guided by our Hand Therapy team. Solid union may not occur for three months following your surgery. In a very small percentage of patients the scaphoid bone may still not heal, requiring possible further surgery.
Other treatment options
Available treatment for wrist scaphoid non-union
Simple interventions such as regular analgesia, activity modification, splints and steroid injections should be tried before surgical intervention is considered. There are a number of surgical options for painful wrist arthritis
Wrist denervation
This operation involves removing the small nerves that supply sensation to the wrist joint. This will have no detrimental effect to the sensation to the hand/fingers. This procedure can provide benefit, relieving pain, in patients for several years.
Partial wrist fusion
In some cases, where only part of the wrist is arthritic, only part of the wrist is fused together. Some of the wrist bones are also removed. This operation maintains some of the wrist movement (approximately half). This operation is however only appropriate in a small number of people.
Proximal Row Carpectomy
This operation involves removing the nearside row of the wrist bones. This is again only appropriate for some patients in which the other articular surfaces are healthy. Again this procedure will maintain some wrist movement.
Wrist Fusion
Wrist fusion (or arthrodesis) is an operation in which the moving surfaces of the wrist are removed in order to fuse those joints together. This will be helped by packing bone graft around the joints. A specially designed plate and screws (or occasionally a metal pin) will be used to stabilise the bones while they heal. The bone graft is taken from either the wrist area or the pelvis/hip bone. Wrist fusion may be considered as a revision type procedure should a wrist replacement fail or loosen.