Wrist Pain: Why is my wrist hurting, Doc? The ulnar side of the wrist.

There are so many causes of wrist pain that it’s sometimes hard to decide where to start.  It would probably be best to define some terms so that we all know what we’re talking about.  There are two terms that are used to describe the location of problems around the wrist.  Hand surgeons use the words radial and ulnar to describe the areas where wrist problems occur.  These are named after the radius and ulnar bones, which are the two bones that connect the wrist to the elbow.  Radial refers to the side of the wrist  where the thumb is located, whereas ulnar refers to the side of the wrist where the little finger is.  There aren’t too many problems that involve both the radial and ulnar sides of the wrist so by splitting the wrist up into two sides we can usually get a better handle on what’s causing wrist pain.  This blog will deal with the ulnar side of the wrist, and next time I’ll go into common causes of radial sided wrist pain.

The most common cause of ulnar sided wrist pain that I see in my office is due to either irritation or tearing of a cartilage in the wrist.  This has the elegant name of the triangular fibrocartilage, or TFCC for short.  The TFCC is a cartilage that helps hold together the radius and ulnar bones at the wrist.  A number of other ligaments and tendons are involved in providing wrist stability, but the TFCC undergoes a lot of stress form normal day to day use of the hand and wrist.  The main stress on the cartilage is caused turning the hand over flat so that your palm faces the floor (known as pronation) and turning your palm up towards the ceiling (known as supination).  Since we’re constantly performing these actions, the TFCC undergoes a lot of stress, and as we age the cartilage can tear.  Most of the time a torn TFCC cartilage doesn’t cause any pain or problems but sometimes the cartilage gets irritated and starts to cause pain and swelling on the ulnar side of the wrist.  Some patients will have catching and popping in their wrists.  There is a soft spot on the ulnar side of the wrist between the ulna and the other wrist bones and this is where the TFCC is located.  That’s where people are tender when they have an irritated TFCC.  The good news is that most tears will calm down with rest, splinting, and non-steroidal anti inflammatory drugs such as Advil or Alleve.  If those conservative measures don’t work then cortisone shots can be very effective in getting rid of the pain and irritation.  In a small number of cases arthroscopic surgery can be performed to debride or clean out the cartilage.

Another common area of pain on the ulnar side of the wrist comes from a wrist tendon that runs right above the TFCC called the extensor carpi ulnaris tendon, or ECU for short.  The ECU runs in a sheath just over the TFCC and helps the TFCC hold the radius and ulna together at the wrist.  Thus the ECU is subject to much of the stress and strain that the TFCC is, and some people will actually have problems with both the TFCC and the ECU.  The ECU tendon can get irritated in it’s sheath and becomes inflamed and irritated.  The treatment of ECU tendonitis is basically the same as for the TFCC.  Rest. splints and medication can help, cortisone shots work pretty well, and for people who don’t get better surgery can be performed to clean out the tendon sheath.

The problems I’ve described are usually chronic in nature and occur without an specific injury such as a fall or car accident.  However both the TFCC and the ECU tendon can be damaged from a distinct, acute injury.  The acute injuries can also be treated by conservative means such as splints or cortisone injections, but it’s probably a little more common to have to have some sort of surgery in the acute situation.

There are other causes of wrist pain along the ulnar side of the wrist but they are much less common that the two we’ve already discussed.  People can develop growths such as ganglion cysts on the ulnar side of the wrist, but they are fairly rare.  In addition, a certain group of patients will have a situation where the ulna bone is a little longer than the radius bone at the wrist.  This can cause the ulna to bang into the wrist bones and cause many problems, including tearing the TFCC and some of the wrist ligaments.  This is called ulnar abutment syndrome and can often require surgery to clean out the wrist and shorten the ulna so it won’t keep causing problems.  A few patients will have arthritis where the radius and ulna meet, which usually causes catching and grinding in the wrist.

Most of the problems on the ulnar side of the wrist can be diagnosed through the history and and examination by the surgeon.  X-rays are usually needed to make sure there isn’t any arthritis or to see if there is evidence of ulnar abutment syndrome.  Occasionally an MRI is useful if the diagnosis isn’t clear from the history, exam and xrays.

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