Dr Steve Carter
The scaphoid is the most important bone in the wrist: It links the proximal carpal row to the distal carpal row, and is critical in the normal functioning of the wrist.
The scaphoid has a very poor blood supply. There is only one artery, as opposed to most other bones which have a double blood supply the scaphoid only has a single supply. So one of the big problems is getting the scaphoid to heal, because of the poor blood supply. The other big issue is diagnosing the scaphoid fracture, as it very often only feels like you have sprained your wrist, so the patient often seeks medical attention only at a later date.
The mechanism of injury is a fall on an outstretched wrist, be it rugby, skateboarding, mountain biking or other activities. When the wrist is loaded in extension the scaphoid is caught in a so called nutcracker effect and snaps at the waist.
As mentioned above, the symptoms may be mild, it feels more like a badly sprained wrist, occasionally may have swelling, pain and loss of movement in the wrist and loss of grip strength.
Diagnosis is by careful clinical investigation. There is often pain in the so called snuffbox at the base of the thumb.
If there is a high index of suspicion, the patient is sent for special xrays called scaphoid views to outline the fracture. If there is no fracture on the xrays with a high index of clinical suspicion an MRI is performed. It is critical not to miss a scaphoid fracture.
The most common fracture type is through the so called waist of the scaphoid, but you can have a fracture of the proximal pole or distal pole. The treatment depends on what type of fracture is present. As we have mentioned before it is critical that we get the fracture to unite so our approach is vigilant.
If the fracture is missed or fails to unite – one goes on to develop a scaphoid non-union which then goes on to develop severe arthritis of the wrist, so called SNAC (scaphoid non-union advanced collapse). So it is essential that we get your fracture to unite.
Over the last 10 years I have seen and treated many scaphoid fractures and our success and union rate is in excess of 95%.
- If the fracture is undisplaced, less than 1mm shift and no angulation, treatment is conservative with a below elbow cast for 8 to 10 weeks.
- If there is any displacement or shift greater than 1mm, the patient requires surgery to stabilize the fracture to allow it to heal. This is day case surgery done via a small 3cm incision over the wrist and a headless compression screw is placed inside to the bone, so called "Herbert" screw.
- Initially a bulky dressing and backslab is applied. This is removed at day 3 and the patient is placed in a custom made bivalve cast which is worn until the fracture is united, usually at 8 weeks.