FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

SHOULDER DISLOCATION DOESN'T USUALLY REQUIRE SURGERY

Question: I dislocated my shoulder this summer while I was pitching in a baseball game. The doctor in the emergency room put it back in place - what an experience that was! I've since recovered and now have full use of my arm. What are the chances of dislocating my shoulder again?

Answer: The shoulder joint is a complicated structure. The upper arm bone, the humerus, is connected to the shoulder bone, the scapula, with a ball-and-socket type of joint. The shoulder's version of this style of joint allows for great range of movement at the expense of some stability. In other words, the socket - called the glenoid cavity - is so shallow that the relatively large ball - called the head of the humerus - won't stay in its proper place without constant support from the shoulder's muscles and ligaments.

To dislocate a shoulder, the supporting muscles and ligaments must be stretched or torn. This allows the head of the humerus to slide over the rim of the socket. About 2 percent of the population sustains this injury at some time during their lives. In 95 percent of these cases, the humerus comes forward toward the front of the body, producing what we doctors call an anterior dislocation. This is probably what you had. And, as you also noticed, this compresses many pain-sensitive parts. Both the dislocation and replacement ("reduction" in doctor lingo) are quite uncomfortable.

Dislocations of the shoulder can result from relatively minor stress, such as throwing a ball, or from major accidents like a car crash or falling off a ladder. Most dislocations - perhaps as high as 75 percent of them - are sustained by individuals under age 40, with 50 to 60 percent being sports-related. And I find it interesting that right-handed people suffer this injury in the left arm about as often as in the right arm. Likewise, lefties are about as likely to injure their non-dominant side as their dominant one.

In a recent large study, it was found that people who had experienced a dislocation had almost a 50 percent chance of having a second dislocation, either of the same or the opposite shoulder. That isn't particularly great news. A somewhat brighter bit of information is that only 23 percent of those who had suffered dislocations had multiple recurrences that required surgery to "tighten up" the shoulder. The remaining 77 percent had one or two additional episodes, then their shoulders became more stable. Unfortunately, we don't know why these people got better and others didn't. An additional piece of good news is that only slightly more than 1 percent of those with dislocations developed shoulder arthritis within 10 years after their original injury.

It is important to keep all the shoulder muscles at a high level of fitness to reduce the risk of repeated injury. This is not particularly complicated, but it does require a specific set of exercises to be sure each of the many important muscle groups are strengthened. If you haven't already been instructed in these exercises, you should see your family doctor or physical therapist instead of trying to strengthen your shoulder without guidance. It often takes just one visit to learn the proper technique. It's well worth the time and expense.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.