Oh no, I broke my wrist! The Scaphoid bone.

“What we got here is failure to communicate.  Some men you just can’t reach, so get what we had here last week.  Which is the way he wants it.  Well he gets it!”

Strother Martin as “The Captain” in the movie “Cool Hand Luke”

The wrist is a complicated area, with a large number of tendons and ligaments associated with a large number of bones.  The wrist consists of two large bones, the radius and the ulna, as well as eight smaller bones within the wrist itself.  The radius is the bone that is broken most commonly in the wrist, and of the smaller bones the one that breaks the most and causes the most trouble is the scaphoid.  I thought it would be worth some time to discuss fractures of the scaphoid and ways to diagnose and treat a broken scaphoid bone.  By the way, I will use the words “fracture” and “break” interchangeably.  They mean the same thing.

The scaphoid is located on the side of the wrist nearest the thumb.  If you hold your thumb up in the air like you are hitch-hiking you’ll see two tendons coming from the thumb back towards the elbow.  In between those two tendons is a small dip that is called the “anatomic snuffbox”:  this is where the scaphoid lives.  If you break your scaphoid this is where you will have the most tenderness and soreness.

By far the most common way the scaphoid is broken is to fall out onto your outstretched hand.  Sometimes the scaphoid can break during high intensity sports such as football without a clear mechanism.  The interesting thing is that the pain of a scaphoid fracture can be pretty minimal and can actually go away without the bone ever healing.  If you do hurt your wrist it’s also possible for an x-ray not to show the break initially.  This is due to the rather unique shape of the scaphoid.  The scaphoid is usually about an inch and a half long, round, with a curve to the bone.  Scaphoid means “boat” in Greek, but as one surgeon I heard giving a talk said “It doesn’t look like any boat I’ve ever seen.”  Because of this shape it can be hard for the x-ray beam to pass perpendicular  to the fracture line and show the break on an x-ray.  Because of these reasons people can break their scaphoid and never get treated for their injury.  Because the scaphoid has such a poor blood supply it usually doesn’t heal and can cause problems years down the road.

So first, let’s talk about how to diagnose a scaphoid fracture.  Let’s say you’ve fallen on your wrist, it hurts in the snuffbox area, and your x-rays don’t show a break.  There are two reasonable options at this stage.  You can wear a brace for 10-14 days and then get another x-ray.  Almost every scaphoid fracture with show up in this time frame and you can still make a treatment decision at that time.  If you didn’t want to wait then MRI has been shown to be the best way to diagnose a scaphoid fracture.  Either choice is reasonable and really depends on the patient and treating physician deciding to choose which way to proceed.

If the scaphoid is broken, then you usually have to make a decision whether to try and treat the broken bone with a cast or surgery.  First off, if there has been a delay in diagnosing the fracture, then surgery is almost always necessary.  If the fracture is recent, probably less than 6 weeks old or so, then you have to evaluate several factors to decide is surgery is needed.  One of these factors is the location of the fracture, that is, which part of the bone is broken.  The scaphoid runs from the wrist to the base of the thumb, and the end that is towards the thumb has a much better blood supply than the end that is near the wrist.   Fractures from the middle of the bone towards the thumb can heal pretty well with a cast, providing the fracture is not displaced or spread apart.  Fractures that are in the third of the bone closest to the wrist have a hard time healing with a cast and often require surgery.

The other factor to consider, which I mentioned early, is whether or not the fracture is displaced. In reality only fractures that are non-displaced (which means that there is a crack in the bone with no separation) can heal without surgery.

If your scaphoid fracture looks like it will heal without surgery, then wearing a cast in an option.  Most physicians use a short cast, below the elbow, with the thumb included in the cast.  Most fractures require a minimum of 6 weeks in a cast, and it can often take up to twice that long for the bone to heal properly.  Again, this is only a treatment available for acute, non-displaced fractures of the scaphoid.

For almost all other scaphoid fracture surgery is indicated.  An incision can be made on either the top or the bottom of the wrist and a screw can be placed across the break.  There are a number of headless screws available which can be placed inside the bone and won’t need to be removed.  The healing rate for both surgery and treatment with a cast are over 90%, which means that most but not all fractures will heal without any problems.

Another option for non-displaced scaphoid fractures is a placement of a screw over a pin placed through the skin.  This is called “percutaneous” screw fixation, and if a surgeon is experienced in this technique it is a safe and effective way to fix the scaphoid and avoid and extended period of time in a cast.  It’s important to discuss the pros and cons of these treatments with your physician to try and figure out what is the best solution for each person and their fracture.

So, what if your fracture was never diagnosed or didn’t heal after the initial treatment?  This is called a scaphoid non-union, and that will be the topic of my next post.

 

 

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