The scaphoid is one of eight small bones of the wrist known as carpal bones. A number of factors make the management of scaphoid fractures particularly challenging at times – probably why the scaphoid has developed somewhat of a bad reputation.
The first challenge is often to actually diagnose that a scaphoid fracture has occurred. The scaphoid is a small, irregular shaped bone and fractures can often be hard to appreciate on plain x-rays – in fact up to 30% of scaphoid fractures are unable to be seen on initial x-rays.
In the past patients would be sent for repeat x-rays in 7-10 days to see if a fracture had become more obvious or sometimes even placed into a cast for 6-8 weeks ‘just in case’ there was a fracture. These days, however, advanced imaging modalities are commonly used to confirm a diagnosis immediately. Early CT or MRI scanning is a far more sensitive method of diagnosing scaphoid fractures at the time of injury so that the correct treatment can be implemented as soon as possible.
Another problem with scaphoid fractures is the potential for non-union – that is when the fracture does not heal. The scaphoid is prone to this complication predominantly due to the limited blood supply of the scaphoid, which for whatever reason comes from the distal (far end) back towards the proximal pole (near end). Non-union is much more common when there is a delay in diagnosing and treating scaphoid fractures appropriately.
If scaphoid non-union does occur, the mechanics of the entire wrist joint can be affected, leading to a very predictable pattern of collapse and arthritis known as SNAC wrist. Sadly, it is not uncommon for patients to present for the first time and already have established arthritis of the wrist some 8-10 years after an innocuous ‘wrist sprain’ that was in fact a scaphoid fracture.
The problems with scaphoid non-union highlight the importance of timely and comprehensive assessment by a hand and wrist specialist should you have any concerns about a possible scaphoid fracture.
Treatment of Scaphoid Fractures
The appropriate management of scaphoid fractures depends on a number of factors – some related to the fracture itself and others related to the patient. It is pertinent to mention how detrimental the effect of smoking can be on scaphoid fracture healing. There are many health reasons to quit smoking but maximising the chances of your scaphoid fracture healing is another really good one!
If treated non-operatively, the wrist is placed into a cast, usually for 6-8 weeks depending on the exact location of the fracture. Recently evidence has emerged that there is no added benefit from including the thumb in the cast so old fashioned scaphoid (thumb spica) casts are no longer used. Once the cast is removed you will gradually regain movement and strength in your wrist, often under the guidance of a hand therapist. To confirm that the fracture has healed Dr Alexander will routinely perform a CT scan 3-4 months after your injury. This ensures that at the end of your treatment you will know for sure that your scaphoid is not going to cause you long term wrist problems in the future.
Surgery for Acute Fractures
For displaced fractures, surgery will be required to reduce the fracture and hold it in position, usually with a screw. Even in undisplaced fractures there is an argument to perform surgery the secure the scaphoid fracture with a screw. This has been shown to dramatically reduce return to work time as well as improve the rates of scaphoid union. Often this screw can be inserted through a very small skin incision, essentially under x-ray guidance.
Following screw fixation of acute fractures, there is usually no need for prolonged cast immobilization, allowing you to start moving and using your wrist earlier.
Surgery for Scaphoid Non-Union
Once non-union has occurred, treatment becomes much more complex and the rates of successful union are much less. The exact treatment required will depend on how long the non-union has been present and how much collapse or arthritis is present. Another factor to consider is whether part of the scaphoid has lost its blood supply and died (avascular necrosis).
One of the most common ways that we can try to get a non-union to heal is by surgically removing scar tissue from the site of non-union so that there is only healthy bone remaining, then inserting bone graft (usually obtained from the iliac crest) and securing the scaphoid with a screw. It is not uncommon to be placed into a cast for 6-8 weeks following surgery for non-union of the scaphoid to maximize the chances of achieving union.
As you can see, scaphoid fractures can be particularly tricky. Dr Alexander will take the time to comprehensively assess your injury and then discuss in detail which treatment option may best suit your circumstances.