A total or partial wrist fusion is reserved for patients with severe degenerative arthritis within the wrist joint. The surgery aims to remove the affected joint surfaces and allows the affected bones to join together. This prevents painful movement at the degenerate joint surfaces.
In cases of limited arthritis, affecting only some of the joint surfaces within the wrist, a partial fusion of the smaller bones of the wrist can be achieved. The advantage of this is that some movement may still be preserved within the wrist joint. In many cases however the degenerative change will be more widespread and a full wrist fusion will be necessary.
Although the operation sounds drastic, fusing or stiffening the wrist in a comfortable position is an effective way of providing pain relief. It is only when patients have very limited, painful movement that a fusion would be considered.
The operation is performed under general anaesthetic. An incision is made along the back of the wrist. The wrist joint is opened and any remaining cartilage on the joint surfaces is removed. The hard outer layer of bone on the joints is also removed. This exposes the healthier soft bone surfaces that will grow together. The joint is then reduced into a neutral position and held securely with a plate. The plate is screwed to the radius and to the small bones in the wrist to provide stability.
The wounds are then closed in layers. Care is taken to ensure that the tendons glide freely.
Local anaesthetic is injected to provide good post-operative pain relief. The wound is dressed and a plaster of paris slab is applied to provide some support.
Patients are kept overnight with their hand elevated. Most patients are comfortable enough to be discharged the day after surgery. They need to continue with their hand in an elevated position to help reduce the risk of swelling. There is often quite extensive swelling following a wrist fusion. Patients may experience some blistering of the skin.
Patients are reviewed at the two-week stage for removal of sutures and they often will require ongoing immobilisation for the first six weeks to protect the fusion site. At the six-week stage, x-rays are performed to check for union of the bones.
Even with the wrist fused in a neutral position, patients are still able to use their fingers freely and should be able to rotate the forearm freely.
As with every operation, there is a risk of infection with a wrist fusion. Antibiotics are administered at the time of surgery to reduce the risk of infection. If the patient does develop infection, this can reduce the chance of the bones fusing together satisfactorily.
Even without an infection, there still is a risk of non-union developing at the fusion site. This is more common in patients who are systemically unwell. Patients who have diabetes or who smoke are at increased risk of non-union.
Despite the permanent restriction in movement, most patients are very satisfied with wrist fusing surgery. By the time patients get to the point of requiring a fusion, they usually have a very restricted range of movement due to pain. A fusion is an effective way of reducing this discomfort.