What is the scaphoid?
The scaphoid is the most commonly injured of the carpal bones. We have eight total carpal bones set in two rows. The scaphoid ‘bridges’ both rows of bones, which is why it is commonly fractured in a fall.
Who gets a scaphoid fracture?
Most scaphoid fractures occur in males, with an average age of 25. Up to 61% of scaphoid fractures occur during a sporting event. Furthermore, because of the nature of those typically injured, they can often present weeks or months following the injury with an unhealed fracture.
Why is a scaphoid fracture so difficult to treat?
First, the scaphoid bone can suffer a non-displaced fracture that does not show up on routine x-rays. The bone itself is in the shape of a twisted peanut, making visualization difficult. This may lull patients into a false sense of security of thinking the bone isn’t broken just because initial x-rays were read as ‘normal’. However, a non-displaced fracture can easily transition into a displaced fracture if not detected and immobilized.
Second, the blood supply to the scaphoid comes from distal or hand side–this means the blood supply comes through the bone, not into the bone. Therefore, the blood supply is disrupted if the bone is broken, which can cause the bone to heal properly and, in some cases, even die.
How do we diagnose and treat a scaphoid fracture?
A high index of suspicion is needed when treating carpal bone fractures. Pain in the “snuff box” or the depression over the wrist on the thumb side is a key sign of carpal fractures. Typically, routine X-rays are taken, but if the pain is present and radiographs are normal, a splint is still worn for two weeks. MRI is very sensitive to picking up scaphoid fractures and can be used when casting is a problem.
Almost all scaphoid fractures will need a CT scan to delineate the fracture pattern and level of displacement. Furthermore, a CT scan is the best method to monitor healing. Unfortunately, this consistent use of CT is difficult in today’s insurance pre-authorization driven environment.
How do we treat scaphoid fractures?
Non-displaced scaphoid fractures can be treated in a cast. A non-displaced fracture will have less than 1mm of a ‘step -off’ or gap at the fracture site and are usually found in younger children. Any complete fracture will need operative fixation. In minimally displaced fractures, this is done with a screw, but sometimes bone grafting is needed because the fracture is comminuted or in multiple pieces.
How long does it take a scaphoid to heal?
Unfortunately, it takes a long time for a scaphoid fracture to heal. Average time to healing is three to four months. A study performed in the Navy found that non-displaced scaphoid fractures treated with a screw could go back to work at eleven weeks on average; patients treated with casting took one to two weeks longer.
What is a scaphoid non-union?
When a scaphoid is not treated properly or has failed treatment the bone may not heal. The lack of blood supply discussed above combined with motion at the fracture site keep the bone from healing. Scaphoid nonunions are particularly hard to treat, even though a myriad of treatments is available to treat them. The goal of surgical treatment is to prevent arthritis, but in any case, the results of scaphoid non-union surgery are inferior to acute surgery, hence the push to evaluate wrist pain early after injury.