19 Year Old Male, Fall
1. Describe any pertinent findings.
2. Does the additional magnified view add or modify your impression from the original series.
There is a subtle linear lucency through the waist of the scaphoid and a fracture should be suspected.
3. What is your diagnosis? Would you perform any additional follow up?
Suspected scaphoid fracture at the waist. Or perhaps normal if you don't see the subtle linear lucency. If you see a lucency and would like to perform an additional study or studies which may help confirm, then angulated scaphoid and/or ulnar deviation views may be beneficial. Subtle fracture not readily seen on x-rays taken immediately after an injury may be better seen on repeat studies taken 7-14 days later due to bony resorption along the margins of the fracture that occurs in the early stages of healing.
4. If the patient was experiencing pain in the anatomic snuff box, would this alter your diagnosis or treatment plan?
Snuff box pain should raise the clinical index of suspicion for scaphoid fracture, regardless of whether a fracture is seen on initial radiographs.
Discussion
Scaphoid fractures are the most common carpal fracture and can occur an any age. They may occur as a result of direct trauma or fall with dorsiflexion or forceful extension and radial deviation. Clinically, anatomic snuff box pain should raise immediate suspicion of a scaphoid fracture. Weakness, decreased range of motion, decreased grip strength, and pain with radial deviation and flexion may be present.
Fractures may occur at the distal tuberosity, the distal pole, waist or middle, and the proximal pole, with the waist being the most common location (80% of fractures). Non displaced fractures can be radiographically occult immediately post trauma, leading to missed diagnosis in some cases, at least initially. In acute trauma care settings where there is a high clinical index of suspicion for a scaphoid fracture but a negative radiographic study, then MRI or CT may be ordered to aid diagnosis. MRI is the preferred advanced imaging modality as it may also help assess for injury to the scapholunate ligament and other soft tissue. Care should be made to assess the scapholunate distance. A widened distance, referred to as a Terry Thomas or Dave Letterman sign for its visual similarity to the gaps in their front teeth, is highly suggestive of injury to the scapholunate ligament.
Treatment
Conserative treatment is simple immobilization and casting. Up to 95% of non displaced or non complicated fractures heal without incident. Displaced fractures are reduced with Kirschner wires (K wires) or with a Herbert screw.
Complications
Failure to properly heal (non union), malunion or pseudarthrosis, carpal instability due to scapholunate ligament injury (Dorsal Intercalated Segmental Instability), and secondary osteoarthritis may all occur. There is also risk for avascular necrosis (AVN). Because of the vascular supply to the scaphoid, fractures at the proximal pole are at risk for developing AVN with estimates ranging between 14-39% of cases. Delayed or non union also increase the risk for AVN. Rarely both proximal and distal poles of the scaphoid may develop AVN. Radiographic evidence of sclerosis within the proximal pole is suggestive of avascular necrosis and is seen 3-6 months after the initial injury.
Delayed diagnosis and treatment of a scaphoid fracture increases the chance of developing complications. Because non displaced scaphoid fractures are often radiographically occult, it is important to develop good clinical judgement when it comes to diagnosis in order to minimize the risk of complication. If the patient's clinical history and presentation are highly suggestive of a scaphoid fracture:
There is a subtle linear lucency through the waist of the scaphoid and a fracture should be suspected.
3. What is your diagnosis? Would you perform any additional follow up?
Suspected scaphoid fracture at the waist. Or perhaps normal if you don't see the subtle linear lucency. If you see a lucency and would like to perform an additional study or studies which may help confirm, then angulated scaphoid and/or ulnar deviation views may be beneficial. Subtle fracture not readily seen on x-rays taken immediately after an injury may be better seen on repeat studies taken 7-14 days later due to bony resorption along the margins of the fracture that occurs in the early stages of healing.
4. If the patient was experiencing pain in the anatomic snuff box, would this alter your diagnosis or treatment plan?
Snuff box pain should raise the clinical index of suspicion for scaphoid fracture, regardless of whether a fracture is seen on initial radiographs.
Discussion
Scaphoid fractures are the most common carpal fracture and can occur an any age. They may occur as a result of direct trauma or fall with dorsiflexion or forceful extension and radial deviation. Clinically, anatomic snuff box pain should raise immediate suspicion of a scaphoid fracture. Weakness, decreased range of motion, decreased grip strength, and pain with radial deviation and flexion may be present.
Fractures may occur at the distal tuberosity, the distal pole, waist or middle, and the proximal pole, with the waist being the most common location (80% of fractures). Non displaced fractures can be radiographically occult immediately post trauma, leading to missed diagnosis in some cases, at least initially. In acute trauma care settings where there is a high clinical index of suspicion for a scaphoid fracture but a negative radiographic study, then MRI or CT may be ordered to aid diagnosis. MRI is the preferred advanced imaging modality as it may also help assess for injury to the scapholunate ligament and other soft tissue. Care should be made to assess the scapholunate distance. A widened distance, referred to as a Terry Thomas or Dave Letterman sign for its visual similarity to the gaps in their front teeth, is highly suggestive of injury to the scapholunate ligament.
Treatment
Conserative treatment is simple immobilization and casting. Up to 95% of non displaced or non complicated fractures heal without incident. Displaced fractures are reduced with Kirschner wires (K wires) or with a Herbert screw.
Complications
Failure to properly heal (non union), malunion or pseudarthrosis, carpal instability due to scapholunate ligament injury (Dorsal Intercalated Segmental Instability), and secondary osteoarthritis may all occur. There is also risk for avascular necrosis (AVN). Because of the vascular supply to the scaphoid, fractures at the proximal pole are at risk for developing AVN with estimates ranging between 14-39% of cases. Delayed or non union also increase the risk for AVN. Rarely both proximal and distal poles of the scaphoid may develop AVN. Radiographic evidence of sclerosis within the proximal pole is suggestive of avascular necrosis and is seen 3-6 months after the initial injury.
Delayed diagnosis and treatment of a scaphoid fracture increases the chance of developing complications. Because non displaced scaphoid fractures are often radiographically occult, it is important to develop good clinical judgement when it comes to diagnosis in order to minimize the risk of complication. If the patient's clinical history and presentation are highly suggestive of a scaphoid fracture:
- Take good x-rays and the right x-rays. PA and lateral views only are not sufficient to diagnose a fracture. A more thorough examination should include PA with ulnar deviation and oblique studies as well. An angulated scaphoid view may also be useful.
- If the first radiographic study is negative, understand this does not necessarily rule out a fracture. Refer for MRI or re-take the x-rays in 7-14 days.
- In the case of a visible fracture, care must be taken to determine if there is displacement or rotation of a fracture fragment. This can be done using x-rays, CT, MRI, or any combination thereof. Displaced fractures are at higher risk for developing complication and require reduction and fixation to improve the chances of healing.
- Remember to assess the lunate for tilting, typically dorsal, and assess the scapholunate distance (considered normal up to 4-5 mm in width). Evidence of lunate tilting and/or a widened space are suggestive of a scapholunate ligament tear. Missed or improperly treated, the scapholunate interval may progressively widen, leading to collapse, instability, and progressive and painful osteoarthritis.
- Follow up at regular intervals is recommended to follow the progress of healing. Development of sclerosis within the proximal pole should raise suspicion for avascular necrosis. MRI or in some cases bone scan may be used in follow up to confirm AVN.
Post-op radiographs in the same patient. The fracture was reduced and fixed with an Accutrak screw. Note how the fracture line is much more obvious, likely due to resorption seen in early healing. No obvious callus at this time. No radiographic features of possible AVN.