Shoulder instability means that the shoulder joint is too loose and is able to slide around too much in the socket. In some cases, the unstable shoulder actually slips out of the socket. If the shoulder slips completely out of the socket, it has become dislocated. If not treated, instability can lead to arthritis of the shoulder joint.
Dislocations happen when a force overcomes the strength of the rotator cuff muscles and the ligaments of the shoulder. Nearly all dislocations are anterior dislocations, meaning that the humerus slips out of the front of the glenoid. Only three percent of dislocations are posterior dislocations, or out the back.
Sometimes the shoulder does not come completely out of the socket. It slips only partially out and then returns to its normal position. This is called subluxation.
Shoulder instability often follows an injury that caused the shoulder to dislocate. This initial injury is usually fairly significant, and the shoulder must be reduced. To reduce a shoulder means it must be manually put back into the socket. The shoulder may seem to return to normal, but the joint often remains unstable. The ligaments that hold the shoulder in the socket, along with the labrum (the cartilage rim around the glenoid), may have become stretched or torn. This makes them too loose to keep the shoulder in the socket when it moves in certain positions. An unstable shoulder can result in repeated episodes of dislocation, even during normal activities. Instability can also follow less severe shoulder injuries.
In some cases, shoulder instability can happen without a previous dislocation. People who do repeated shoulder motions may gradually stretch out the joint capsule. This is especially common in athletes such as baseball pitchers, volleyball players, and swimmers. If the joint capsule gets stretched out and the shoulder muscles become weak, the ball of the humerus begins to slip around too much within the shoulder. Eventually this can cause irritation and pain in the shoulder.
A genetic problem with the connective tissues of the body can lead to ligaments that are too elastic. When ligaments stretch too easily, they may not be able to hold the joints in place. All the joints of the body may be too loose. Some joints, such as the shoulder, may be easily dislocated. People with this condition are sometimes referred to as double-jointed.
Chronic instability causes several symptoms. Frequent subluxation is one. In subluxation, the shoulder may slip (sublux) in certain positions, and the shoulder may actually feel loose. This commonly happens when the hand is raised above the head, for example while throwing. Subluxation of the shoulder usually causes a quick feeling of pain, like something is slipping or pinching in the shoulder. Over time, you may stop using the shoulder in ways that cause subluxation.
The shoulder may become so loose that it starts to dislocate frequently. This can be a real problem, especially if you can’t get it back in the socket and must go to the emergency room every time. A shoulder dislocation is usually very obvious. The injury is very painful, and the shoulder looks abnormal. Any attempted shoulder movements cause extreme pain. A dislocated shoulder can damage the nerves around the shoulder joint.
If the nerves have been stretched, a numb spot may develop on the outside of the arm, just below the top point of the shoulder. Several of the shoulder muscles may become slightly weak until the nerve recovers. But the weakness is usually temporary.
Your doctor will diagnose shoulder instability primarily through your medical history and physical exam. The medical history will include many questions about past shoulder injuries, your pain, and the ways your symptoms are affecting your activities.
In the physical exam, your doctor will feel and move your shoulder, checking it for strength and mobility. Your doctor will stress the shoulder to test the ligaments. When the shoulder is stretched in certain directions, you may get the feeling that the shoulder is going to dislocate. This is a very important sign of instability. It is called anapprehension sign. (Don’t worry. Unless your shoulder is extremely loose, it will not dislocate.)
Your doctor may order an X-ray. X-rays can help confirm that your shoulder was dislocated or injured in the past.
If your doctor is unsure about the diagnosis, you may need to undergo further tests. A surgeon may need to examine your shoulder using an arthroscope while you are under general anesthesia, which puts you to sleep. An arthroscope is a tiny TV camera inserted into the shoulder through a small incision. This allows a good look at the muscles and ligaments of the shoulder. When you are awake, it is hard to test the ligaments because you automatically tighten the muscles during the exam.
When you go to the doctor with a dislocated shoulder, X-rays are necessary to rule out a fracture. X-rays are usually done after the shoulder is put back into joint. This allows your doctor to make sure the joint is back in place.
Your doctor’s first goal will be to help you control your pain and inflammation. Initial treatment to control pain is usually rest and anti-inflammatory medication, such as aspirin or ibuprofen. Your doctor may suggest a cortisoneinjection if you have trouble getting your pain under control. Cortisone is a strong anti-inflammatory medication.
Your doctor will probably have a physical or occupational therapist direct your rehabilitation program. At first, patients are shown ways to avoid positions and activities that put the shoulder at further risk of injury or dislocation. Overhand athletes may be issued a special shoulder strap or sleeve to stop the shoulder from moving in ways that strain it.
Your therapist may use heat or ice treatments to ease pain and inflammation. Hands-on treatments and various types of exercises are used to improve the range of motion in your shoulder and nearby joints and muscles. Later, you will do strengthening exercises to improve the strength and control of the rotator cuff and shoulder blade muscles. Your therapist will help you retrain these muscles to keep the ball of the humerus in the socket. This will improve the stability of the shoulder and help your shoulder joint move smoothly.
You may need therapy treatments for six to eight weeks. Most patients are able to get back to their activities with full use of their arm within this amount of time.
If your therapy program doesn’t stabilize your shoulder after a period of time, you may need surgery. There are many different types of shoulder operations that have been developed and used in the past to stabilize the shoulder. Almost all of these operations attempt to tighten the ligaments that are loose. The loose ligaments are usually along the front or bottom part of the shoulder capsule.
Surgery on the shoulder has improved dramatically over the past two decades. many of the procedures that have been developed in the past have been abandoned altogether. Today, surgery that is performed for stabilizing an unstable shoulder is most commonly done using the arthroscope.
The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
sources include: Houston Medical
OrthoWashington in Kirkland, WA is a premiere orthopedic practice and surgery center with surgeons and doctors serving patients in the greater Bellevue and Seattle areas.
Disclaimer: The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this website.
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