Scaphoid Fractures
What are scaphoid fractures?
The scaphoid bone is one of eight small bones that make up the
“carpal bones” of the wrist. There are two rows of
bones, one closer to the forearm (proximal row) and the other closer to
the hand (distal row). The scaphoid bone is unique in that it
spans the two rows (see Figure 1). This puts it at extra risk
during injury, which accounts for it being the most commonly fractured
carpal bone by far.
How do scaphoid fractures occur?
Fracture of the scaphoid bone occurs most frequently from a fall onto
the outstretched hand. Typically there is pain initially, but the pain
may decrease after days or weeks. Bruising is rare, and swelling
may be minimal. Since there is no deformity, many people with this
injury mistakenly assume that they have just sprained their wrist,
leading to a delay in seeking evaluation. It is common for people
who have fractured this bone to not become aware of it until months or
years after the event.
Diagnosis of scaphoid fractures
Scaphoid fractures are most commonly diagnosed by x-rays of the
wrist. However, when the fracture is not displaced, x-rays taken
within the first week may not reveal the fracture. A non-displaced
scaphoid fracture could thus be incorrectly diagnosed as a
“sprain” because the x-ray was “negative.”
Therefore a patient who has significant tenderness directly over the
scaphoid bone (which is located in the hollow at the thumb side of the
wrist, or “snuffbox”) should be suspected of having a
scaphoid fracture and be splinted (see Figure 2). The patient
should be re-evaluated about two weeks later, and if findings are still
suspicious for a scaphoid fracture, x-rays at that time will usually
show the fracture due to changes in the bone at the edge of the
fracture. In cases where waiting two weeks in a splint may cause
undue hardship, or if the x-rays remain negative but the clinical exam
is still suspicious, more sophisticated (and expensive) imaging
techniques may be utilized, such as CT scan, bone scan, or MRI.
Treatment of scaphoid fractures
If the fracture is non-displaced, it could be treated by
immobilization in a cast. The cast usually covers the forearm,
hand, and thumb, and sometimes includes the elbow for the first phase of
immobilization. Although the fracture may heal in as little as 6
weeks, the healing can often be delayed. One reason for this delay
is the variable blood supply to different parts of the scaphoid
bone. The fracture can disrupt the bone’s blood supply,
impairing the healing. Part of the bone might even die after fracture
due to loss of its blood supply, particularly in the proximal
third of the bone, the part closest to the forearm. If the fracture is
in this zone, or if it is at all displaced, surgery is more likely to be
recommended. With surgery, a screw or pins are inserted to stabilize the
fracture, often with a bone graft to help heal the bone (see Figure 3).
Sometimes screw fixation surgery is recommended—even in
non-displaced cases—so as to avoid prolonged casting.
Complications of scaphoid fractures
Non-union: If a scaphoid fracture goes unrecognized, it often will
not heal. Sometimes, even with treatment, it may not heal because of
poor blood supply. Over time, the abnormal motion and collapse of the
bone fragments may lead to mal-alignment within the wrist and subsequent
arthritis. If caught before arthritis has developed, surgery may be
performed to try to get the scaphoid to heal.
Avascular necrosis: A portion of the scaphoid may die because
of lack of blood supply, leading to collapse of the bone and later
arthritis. Again, if arthritis has not developed, surgery to try to
restore circulation to the bone may be attempted.
Post-traumatic arthritis: If arthritis has already developed,
salvage-type procedures may be considered, such as removal of
degenerated bone or partial or complete fusion of the wrist joint.

Figure 1: The scaphoid bone is unique in that it
spans the two rows of wrist bones.

Figure 2: Significant tenderness directly over
the scaphoid bone (which is located in the hollow at the thumb side of
the wrist).

Figure 3: A screw or pins are placed to
stabilize the fracture.
© 2006 American Society for Surgery of the Hand
Developed by the ASSH Public Education Committee
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