Why is this fracture special?
The scaphoid bone connects the two rows of carpal bones and is involved in almost all movements of the hand. Its blood supply is arranged in an unusual way: the vessels enter the bone at the far edge and feed it in the opposite direction. If the fracture line is closer to the forearm, the proximal fragment is effectively cut off from the bloodstream and may gradually die. Hence the high incidence of nonunion and avascular necrosis during late treatment. The closer the fracture is to the wrist, the longer the healing and the stricter the requirements for fixation.
- Waist (middle) fracture is the most common option
- Proximal pole fracture - heals worst
- Distal pole fracture - heals faster
- Reverse blood supply to bone
- Risk of pseudarthrosis and avascular necrosis
- Late development of wrist arthrosis in the absence of treatment
How does injury occur?
A typical mechanism is a fall on an extended hand with emphasis on the palm, when the body weight is transmitted through the wrist. This happens on slippery floors, on ice, when falling from a bicycle, skateboard or motorcycle, and in contact sports. Less commonly, the cause is a direct blow to the base of the palm, such as kickback of the handle. Young active men are more often affected. In children, the same mechanism usually breaks the radius, and in older people, its far end, so a fracture of the scaphoid is characteristic of young adults.
- Fall onto an extended hand with emphasis on the palm
- Falling from a bicycle or motorcycle
- Contact and team sports
- Direct blow to the heel of the palm
- Road traffic injury
- More often in young men
Symptoms
The pain is located on the outside of the wrist at the base of the thumb, in a depression that becomes noticeable when the finger is moved to the side - it is called the anatomical snuffbox. Pressing on this point is painful. The hand swells moderately, and there may be no bruising at all. Movement is preserved, but wrist extension and fist clenching are painful, and grip strength is reduced. It is the relatively modest symptoms that are misleading: a person believes that he simply pulled his arm, and consults a doctor weeks or months later.
- Pain in the anatomical snuffbox when pressed
- Moderate swelling of the wrist
- Pain when extending the wrist and clenching the fist
- Reduced grip strength
- Pain with axial load on the thumb
- Mild symptoms with an obvious fracture
Diagnostics: why the first image is normal
X-rays are taken in several special settings, including a picture with ulnar deviation of the hand. However, up to a quarter of fresh fractures are not visible on the first image because the fracture line is still too thin. Therefore, in case of typical pain, the wrist is fixed as if it were fractured and the picture is repeated after 10–14 days, when the fracture zone becomes noticeable. If a quick response is required, a CT scan is prescribed, and the most sensitive method in the first days is an MRI, which shows bone marrow edema immediately. It is impossible to release a patient diagnosed with a bruise without control.
- X-ray of the wrist in special settings
- Fixation and re-imaging after 10–14 days
- CT scan of the wrist and hand
- MRI as the most sensitive method in the first days
- Pressure test in an anatomical snuff box
- Dynamic examination for persistent pain
Treatment
Non-displaced fractures are treated with fixation: a plaster cast or a rigid orthosis with thumb grip is applied. The time frame is significantly longer than for other fractures of the hand: from 6 to 12 weeks, and longer for a fracture of the proximal part of the bone, with control photographs. In case of displacement of fragments, fracture of the proximal pole, and in people for whom it is important to quickly return to work or sports, fixation is performed with a special screw through a small access - this reduces the period of immobilization. When a false joint has already formed, surgery with bone grafting is required. Smoking significantly worsens fusion.
- Cast or thumb brace for 6–12 weeks
- Control shots in dynamics
- Fixation with a compression screw during displacement
- Early surgical treatment for proximal pole fracture
- Bone grafting for pseudarthrosis
- Quitting smoking during the fusion period