The scaphoid bone is the most frequently fractured bone of the wrist, but it remains occult on conventional radiographs in approximately 65 percent of cases. (Radiology 2006;240:169.)
The most common method of injury is a fall on an outstretched hand (FOOSH), and the diagnosis is usually based on clinical presentation and conventional radiographs. Swelling, reduced grip strength, and focal tenderness may be present. Tenderness often presents in one of three places, with anatomic snuffbox tenderness occurring with the most common scaphoid waist fractures. Any tenderness in the snuffbox should be treated as a scaphoid fracture until proven otherwise.
Physicians should take a conservative approach in these cases, and should cast the wrist and follow up with reimaging two to six weeks after the insult. If the findings remain equivocal, MRI of the wrist should be performed for its high sensitivity and specificity.
Three locations of fracture have been described: waist of scaphoid (most common), proximal pole (most problematic), and distal pole. The scaphoid bone's blood supply mostly comes from the dorsal scaphoid branch of the radial artery. (J Hand Surg Am 1980;5:508.) The proximal pole's blood supply depends entirely on intraosseous blood flow. (J Hand Surg Am 1980;5:508.)
Healing time highly depends on the location of the fracture, and ranges from three to six months. The peculiarity of the scaphoid's blood supply predisposes it to many complications, the most important one being avascular necrosis. The more proximal the fracture line, the higher the risk of developing AVN. Delayed union and nonunion are less severe complications. Surgical intervention may be needed in unstable nonunion and AVN cases.
The scaphoid bone is one of the most important bones of the wrist because it connects the proximal and distal carpal rows. The initial diagnosis may be clinical, but radiographs play an important role in the assessment and course of treatment. Missed scaphoid bone fractures, even when extremely subtle, may have drastic consequences and lead to instability of the affected joint.
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