Scaphoid fractures


Mr Mike Hayton
FRCS (Trauma and Orth) FFSEM (UK)
Consultant Orthopaedic Hand Surgeon

Other common names

 - Carpal navicular fracture.

Who does it affect?

Approximately 80% of scaphoid fractures occur in males, with the highest incidence occurring between the ages of 20 and 30 years. Overall, it is felt that scaphoid fractures account for 11% of all hand fractures.

Why does it occur?

Patients falling onto an outstretched wrist can apply direct trauma to the wrist. If this trauma is of such a force it can fracture many of the bones in the wrist, and in particular the scaphoid fracture for the purposes of this article.

Symptoms

Patients present with well localised pain in the wrist joint, more towards the thumb side of the wrist. In addition to this, patients may have a decreased range of movement and, in particular, a decreased ability to fully cock the wrist back (known as 'wrist extension').

Clinical examination

Pain can be felt in the various areas that the scaphoid bone can be felt. One of the common areas is the anatomical snuffbox. If the patient cocks their thumb backwards a 'V' shaped groove can be seen around the wrist, and this is a site of scaphoid tenderness. A decreased range of movement may be observed by the doctor. Particularly lack of extension, putting the heels of the hand together and cocking the wrist back will show any asymmetry

.

Special features of this condition

The scaphoid is a boat-shaped bone. Fractures can occur anywhere along its length, but the vast majority (over three-quarters) occur through the centre of the scaphoid (waist). The site of the scaphoid fracture has significant impact on the healing potential. Fractures through the waist of the scaphoid have got a good chance of healing with appropriate treatment (approximately 85%). However, fractures towards the wrist joint (the so-called proximal pole fractures) have an increased risk of the fracture not uniting. This is on account of poorer blood supply to this area of bone. Other risk factors for developing a non-union (i.e. the fracture not healing) are: delay in presentation, significant separation of the fracture fragments, smoking and delay in presentation to a doctor.

Investigations

Plain x-rays are the most common way to diagnose a scaphoid fracture. It can be seen as a line across the scaphoid bone. However, scaphoid fractures occasionally do not show up on the initial x-ray, and in this case if your doctor strongly suspects you have fractured your scaphoid you may be treated in a plaster of Paris, and a repeat x-ray performed in one week. Alternatively, further imaging, such as an MRI scan or a CT scan may be performed.

Non-operative treatment

Some fractures of the scaphoid can be treated in a plaster cast. These are usually the fractures through the waist, which are undisplaced. However, scaphoid fractures that are displaced (i.e. the fracture fragments have moved apart) or fractures in the so-called proximal pole have a higher risk of not uniting, and are often treated operatively. Scaphoid fractures that are treated non-operatively usually involve a plaster of Paris immobilisation for a period of six to twelve weeks. Careful x-ray, follow up and CT scanning may be required to ensure the fracture has united.

Operative treatment

Scaphoid fractures that occur in the proximal pole or scaphoid fractures that are displaced often require operative treatment. Surgery is performed under general anaesthetic or regional anaesthesia (only the arm is made numb). The surgery takes between thirty and forty minutes. A tourniquet is used, which is like a blood pressure cuff around the upper arm, which prevents blood from obscuring the surgeon's view. There are two main types of scaphoid surgery for fractures.

The first is the traditional 'open' surgery. This usually involves a three to four centimetre incision either on the front or the back of the wrist, depending on the site of the fracture. The surgeon identifies the fracture under direct vision and places a bone screw, under x-ray control, into the scaphoid. The screw is buried deep inside the bone and is a permanent implant. After this type of surgery the patient is usually mobilised quickly, and plain radiographs or CT scans are performed to ensure the bone has united.

The second type of surgery is a more modern type of technique, which involves small (two or three millimetre incisions) this is called the 'percutaneous fixation technique'. This had the added advantage of less surgical dissection and, hopefully, less trauma to the surrounding structures. However, the overall healing rate between the percutaneous and open techniques is probably similar. Post-operatively the rehabilitation is often quicker with the percutaneous technique due to less soft tissue trauma. This is a short video clip of Mike Hayton performing a percutaneous scaphoid fixation operation - click here.

This xray shows a screw across the healed fracture site.

Post-operative rehabilitation

The patients are usually mobilised within the first ten to fourteen days' time. Range of movement rapidly returns, before strengthening procedures occur. Sutures are often buried under the skin, and the ends of the suture need to be snipped, usually at ten days. Scaphoid fractures usually require six to eight weeks to heal, and this is confirmed with x-ray or CT scans.

Return to activities of daily living

Patients who are treated operatively, particularly with the percutaneous techniques, can return to driving and many activities of daily living within the first few days. Patients who are treated with more conventional, open four centimetre incisions usually return to driving within two to three weeks. Patients who are treated non-operatively, in a plaster of Paris, often find it difficult to drive whilst the cast is on. Indeed, many insurance companies prevent patients from driving in a cast.

Return to work

Everyone has different work environments. Return to heavy manual labour often occurs after bone healing. Light duties can be tolerated within the first few days.

Complications

Non-union is the major complication of scaphoid fractures. This is an inability for the fracture to heal. It is more common in the proximal pole fractures and those fractures that have significantly displaced. Overall, the non-union rate for scaphoid fractures is about 15%. An untreated scaphoid non-union is thought to go on to develop osteoarthritis over a ten to fifteen year period.

Treatment in plaster of Paris has very few complications, apart from non-union. Occasionally stiffness can occur in the digits if the fingers are not moved early.

Surgery has various complications. These include: infection; damage to blood vessels and nerves; painful scars and intra-operative complications associated with the screw fixation. Generally speaking, the more scaphoid fixations a surgeon performs, the less the specific complications to the surgery occur.