A Patient's Guide to Scaphoid Fracture of the Wrist
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Introduction
Doctors commonly diagnose a sprained wrist after a patient
falls on an outstretched hand. However, if pain and swelling
don't go away, doctors become suspicious that the injury is
actually more serious. A fall on an outstretched hand commonly
breaks the scaphoid bone (also called the navicular
bone) of the wrist. X-rays taken at the time of the injury
may not clearly show the fracture. If the fracture is not
recognized early, it may not heal properly. This can lead
to problems later.
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This document will help you understand
• the anatomy of the wrist joint
• what causes fractures of the scaphoid bone
• what non-union of the scaphoid bone is
• what you can do to treat each condition
Anatomy
Where is the scaphoid bone of the wrist?
The anatomy of the wrist joint is extremely complex--probably the
most complex of all the joints in the body. The joint is actually
a collection of many joints and many bones. These joints and bones
let us use our hands in many ways. The wrist must be extremely mobile
to give our hands a full range of motion. At the same time, the
wrist must provide the strength for heavy gripping.
The wrist is made up of eight separate small bones, called the
carpal bones. The scaphoid bone is a carpal bone near the
base of the thumb. The carpal bones connect the two bones of the
forearm, the radius and the ulna, to the bones of
the hand. The metacarpal bones are the long bones that lie
underneath the palm. The metacarpals attach to the phalanges,
which are the bones in the fingers and thumb.
View close-up of anatomy.
One reason that the wrist is so complicated is because every small
bone forms a joint with the bone next to it. This means that what
we call the wrist joint is actually made up of many small joints.
Ligaments connect all the small bones to each other, and to the
radius, ulna, and metacarpal bones.
The scaphoid bone is a small carpal bone on the thumb side (radial
side) of the wrist. It is the most commonly fractured carpal
bone. This is probably because it actually crosses two rows of carpal
bones, forming a hinge. A fall on the outstretched hand puts heavy
stress on the scaphoid bone. This stress can cause either a small
crack through the middle of the bone or a complete separation of
the bone into two pieces. A separation is called a displaced
fracture.
View anatomy image with scaphoid
fracture.
Causes
What causes a scaphoid fracture?
A scaphoid fracture is almost always caused by a fall on the outstretched
hand. We commonly try to break a fall by putting our hands out for
protection. Landing on an outstretched hand makes hand and wrist
injuries--including a fracture of the scaphoid bone--fairly common.
View of a fall on outstretched
hand.
When a scaphoid fracture is recognized on the first X-ray, treatment
begins immediately. But patients often assume that the injury is
just a sprain, and they wait for it to heal on its own. In some
cases, the wrist gets better. In many cases the bone fails to heal.
The scaphoid fracture then develops into what surgeons call a non-union.
A non-union can occur in two ways. In a simple non-union, the two
pieces of bone fail to heal together. The second type of non-union
is much more serious. The lower half of the fractured bone loses
its blood supply and actually dies. This condition is called avascular
necrosis ("Avascular" means no blood supply, and "necrosis"
means dead.)
The scaphoid bone is at risk for avascular necrosis. Only one small
artery enters the bone, at the end that is closest to the thumb.
If the fracture tears the artery, the blood supply is lost. Avascular
necrosis becomes easy to see on X-rays several months after the
injury.
View of proximal fragment which
can lead to avascular necrisis.
Symptoms
How will I know if I have a scaphoid fracture?
The symptoms of a fresh fracture of the scaphoid bone usually include
pain in the wrist and tenderness in the area just below the thumb.
You may also see swelling around the wrist. The swelling occurs
because blood from the fractured bone fills the wrist joint. Thin
people will see a bulging of the joint capsule. The joint
capsule is the watertight sac that encloses the joint.
Symptoms of a non-union of the scaphoid bone are more subtle. You
may have pain when you use your wrist. However, the pain may be
very minimal. It is fairly common for doctors to see a non-union
of the scaphoid bone on X-rays, but the patient can't remember an
injury. These people probably suffered a wrist injury years ago
that they thought was a simple sprain. Still, the most common symptom
of a non-union is a gradual increase in pain. Over several years
the non-union can lead to degenerative arthritis in the wrist joint.
Diagnosis
What tests will my doctor run?
Your doctor will first take a medical history. You will be asked
questions about your pain and about any injuries to your wrist.
Your doctor will also do a physical exam. The prodding and moving
may hurt your wrist a bit. But it is important that your doctor
know exactly where your pain is coming from.
Doctors should assume that any patient who has fallen on an outstretched
hand and has swelling or tenderness on the thumb side of the wrist
has a scaphoid fracture. You should assume this until tests prove
otherwise. X-rays taken immediately after the injury may not show
a fracture. Still, most surgeons will put a cast on the wrist and
get another X-ray in ten days. This gives the edges of the fractured
bone time to heal, and may prevent non-union. By waiting ten days,
the fracture is easier to see on an X-ray.
View X-ray images:
View X-ray
View artist's enhancement of X-ray
If it is still not clear whether or not you have a fracture, your
doctor may order other imaging tests. You may have a bone scan
done. A bone scan involves injecting "tracers" into your
blood stream. The tracers then show up on special X-rays of your
wrist. The tracers build up in areas of extra stress to bone tissue,
such as a fracture.
Your doctor may also order an MRI scan. An MRI scan is a
special imaging test that uses magnetic waves to create pictures
of your body in slices. The MRI scan shows tendons as well as bones.
It is painless and requires no needles or injections.
Treatment
Can a fracture or non-union be healed?
Fracture
If the fracture is identified immediately and is in good alignment,
you will probably wear a cast for nine to twelve weeks. The cast
will cover your forearm, wrist, and thumb. This is necessary to
hold the scaphoid bone very still while it heals. Your doctor will
take X-rays at least once a month to check the progress of the healing.
Once your doctor is sure the fracture has healed, the cast will
be removed. Even with this type of treatment, there is still a risk
that the fracture may not heal well and will become a non-union.
View of hand in cast.
Some types of fractures have a higher risk for not healing well
and becoming a non-union. In these cases, your doctor may suggest
surgery immediately.
Non-union
A fracture that doesn't heal within several months is considered
a non-union. If the injury is fairly recent, your doctor might recommend
more time in the cast. He or she might also prescribe an electrical
stimulator. The electrical stimulator is a device that sends
a small electrical current to your scaphoid bone. You wear it like
a large bracelet for ten to twelve hours a day. Electrical current
has been shown to help the bones heal.
View of hand with an electrical
stimulator.
Surgical Treatment
If the non-union is quite old, or if the cast and the electrical
stimulator fail to heal the fracture, your surgeon will probably
suggest surgery. In surgery for a scaphoid fracture, the surgeon
first makes an incision in the wrist directly over the scaphoid
bone. The nerves and blood vessels are then carefully moved to one
side. This lets the surgeon see the joint capsule.
 Next
the surgeon finds the old fracture line on the scaphoid bone. All
the scar tissue between the two halves of the bone must be removed.
This creates a fresh bone surface to allow healing to begin again.
Your surgeon may use a bone graft. A bone graft involves
taking bone tissue from another spot in your wrist and inserting
it into the fracture. A bone graft can stimulate healing on the
surface of the bones. The bone graft is usually taken through a
second small incision just above the wrist. (It is sometimes taken
from the pelvis, through an incision in the side of your hip.)
After the bone graft is placed between the parts of the scaphoid
bone, some surgeons also insert a metal pin or screw across the
bone. The goal is to hold the two pieces of bone tightly together,
allowing them to fuse into one bone.
View image of scaphoid fracture
pin placement.
When the surgery is complete, the incision is stitched closed.
The arm is placed in a large bandage or a splint. You are then awakened
and taken to the recovery room.
You will need some type of anesthesia for this type of surgery.
You may get either general anesthesia or a regional block.
General anesthesia puts you totally to sleep. A regional block involves
injecting medications to numb the nerves of the arm. If you are
especially anxious, you may also get medications that allow you
to drift off to sleep. Be sure to discuss your options with your
doctor.
This is usually an outpatient procedure. That means you won't need
to stay overnight in the hospital.
Sometimes the bones still do not heal as planned. Doctors call
a fused bone that fails to heal a pseudarthrosis. If the
non-union continues to cause pain, you may need a second operation.
Your surgeon will probably add more bone graft and check that the
pins or screws are holding the bones together.
Rehabilitation
What will my recovery be like?
If the bone is in good alignment, and there are no problems with
the blood supply to the bone, you'll be placed in a cast for nine
to twelve weeks. Some doctors prefer to start with a long-arm cast.
Others use a thumb-spica cast designed to keep the wrist and thumb
from moving.
The amount of time you need to wear the cast depends on what part
is fractured and whether the bones heal well. When your doctor is
certain the bones have healed, your cast will be removed. Your wrist
will probably be stiff and weak from being in the cast. You may
need physical or occupational therapy to help improve wrist range
of motion and strength.
If you have surgery, you'll be placed in a splint for about twelve
weeks after surgery. Your surgeon will X-ray the wrist several times
after surgery to make sure that the bones are healing properly.
Once the two halves of the scaphoid bone have healed, you can safely
begin a rehabilitation program.
After surgery, you may need physical or occupational therapy sessions
for six to eight weeks. The first few treatments will focus on controlling
the pain and swelling. You will work into doing exercises to help
strengthen and stabilize the muscles around the wrist joint. Other
exercises are used to improve fine motor control and dexterity of
your hand. You'll be given tips on ways to do your activities while
avoiding extra strain on the wrist joint.
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