Loose joints cause slips:
If you're between the ages of 18 and 35 with a shoulder that "slips", it's almost a sure bet the joint is too loose! Two decades ago this usually meant your shoulder was coming partly out of the socket, teetering dangerously near a complete dislocation. A major operation was often needed. It's different now!
Today, a whole galaxy of new shoulder lesions have been discovered by the arthroscope much as the Hubble telescope has located new stars and planets. Within the last decade textbooks on the shoulder have necessarily been re-written. You cannot understand your shoulder problem unless you generally know what they say. This is a summary.
Should I worry?
Yes, IF you are:
A male overhead athlete: pitcher, gymnast, butterfly stroker, raquet sport type Double jointed
Victim of a seizure disorder (muscle contractions may cause sliping of the joint) An addict (alcohol, drugs) relaxation does NOT always protect against injury
Dominant arm - for the shoulder that's giving you problems
Bad news-good news:
You're lucky if your shoulder dislocates with the first injury (usually a fall on the outstretched arm) We're told 75 per cent of shoulder trouble in adults up to age 35 starts this way. Normaly any one can see the shoulder bone isn't underneath the shoulder cap where it's supposed to be. An x-ray will clearly show it's out of the socket and lying over your ribs beneath the collar bone. Keep reading and find instructions on how to put it back in the socket if you're marooned in the far reaches of a national park or desert island. Sometimes you can bind the reduced joint to the chest for three weeks after the first dislocation and it will heal, but if it comes out a second time, surgery is needed to cure it - its not going to cure by itself - that advice should help your primary care physician.
Reserve your pity for the guy in our opening paragraph! Let's talk about him.
What's meant to be:
There's one joint in the shoulder where the action is - the gleno-humeral joint (see illustration). Think of this as the monster troublemaker in both the young and the old shoulder and you've moved immediately to the Nitti gritti.
This joint's as finely engineered as valves on a racing car. The shoulder socket doesn't begin to cover (contain) the shoulder bone and this allows the shoulder to glide through the largest range of motion of any joint in the body. If the joint is too loose , the shoulder bone tends to slide part way out of the socket. This is damaging to the joint and may cause serious trouble if not stopped. Unfortunately, the joint doesn't speak plain English, like "Hey, I'm your shoulder bone and I just slid part way out of the socket!" It speaks in code but some shoulder surgeons are compiling a glossary that might be of use to you readers, that "sliding part way out of the socket" may sound like:
•"There's an ache when I bring my arm overhead"
•"It catches (locks) when I start the pitch"
•"It hurts when I speed the arm up during delivery"
•"It slips when I follow through"
•"It gets tired after a couple of innings and will go dead if I keep on throwing"
•"The pain's right here" (hand clasped over front of deltoid muscle)- see drawing
What's happening inside?
First, if you practice "overhead" sports intensely or long enough, you will stretch out the joint tissues making it susceptible to the slippage that happens in loose joints. When the slipping happens, it causes damage to the parts that are supposed to help keep the shoulder bone in the socket the joint capsule or the labrum (this is like the meniscus cartilages in the knee). Once these are stretched or tom, they do not usually heal without some surgical help.
The capsule is like a sack that surrounds the joint and keeps the joint fluid from spilling out into the surrounding muscles and tendons. It also helps keep the shoulder bone in the socket. The labrum fits over the inside edges of the socket, like the red rubber ring around the top of a Mason jar. When the shoulder bone "slips", it may tear this labrum or strip it from the socket. This sack tissue can get between the socket and shoulder bone and cause the "catches", "locking", "slipping" described by athletes who have the problem. Again, it is not nature's way to heal this problem, it usually has to be reattached through the arthroscope or cut away to allow free movement of the shoulder.
How will I know?
While a good physical examination and x-ray will show a dislocation of the shoulder, stretched capsules and torn labrums don't show up on x-ray. They also are difficult to see on MRI although an MRI made after a dye injection in the joint has a pretty high rate of diagnostic success.
If you're seeing a doctor who's familiar with overhead athletes and their shoulder problems, he'll become suspicious just from the questions he asks you and the answers you give. He will then check for instability (surgeon's word for "looseness"). He may pull your arm bone directly down toward the floor while it's resting against your chest. If the shoulder bone comes down more than I inch from the shoulder cap, it's a sign the joint is loose. Other tests involve placing the shoulder bone under tension with the arm in certain positions to see if this causes slippage or causes the pain that brought you to the doctor. They are complicated and best done by an expert physician.
It may be necessary to perform an arthroscopic examination to make the diagnosis. When this is done, the doctor is often able to correct the trouble at the same time he discovers it. This is most likely an outpatient procedure done at a daytime surgical center.