Shoulder instability, or shoulder dislocations, is actually a very complex issue. Not all shoulder dislocations occur for the same reason. We can have loose ligaments or torn ligaments — we can dislocate our arm forward, backwards or in both directions. You may have had only one dislocation, or you may have had many. Because there are different forms or types of shoulder instability (or shoulder dislocations) we classify them by:
- when they occurred (acuity)
- which direction they occurred (anterior,posterior or multi-directional), and
- the problem or issue that exists within the shoulder to enable to the shoulder to dislocate (labral tears, ligament tears, stretched ligaments or genetically loose ligaments)
Instability or shoulder dislocations results is a situation where the shoulder is loose, and dislocates. Shoulder instability presents as a spectrum of issues. Shoulder instability can occur because you stretched your ligaments slowly over time (overhead sports), or instability (shoulder dislocations) can occur after a single traumatic episode (fall, tackle, etc) which has resulted in a ligament or labral tear. The ligaments and labrum contribute significantly to the stability of our shoulders. The ligaments are attached to the glenoid labrum… a cartilage disc around the socket of the shoulder. IF you tear the labrum, the ligaments are no longer functioning well. This is how a labral tear can lead to shoulder instability or shoulder dislocations.
Shoulder dislocations can also be described in terms of their chronicity; acute vs chronic (fresh vs old) , or the direction of the instability; anterior instability (forwards) , posterior instability (backwards) and mult-directional instability (every direction).
By far the most common form of shoulder dislocation is the traumatic, anterior form. This typically involves a collision on the ball field or a fall on an outstretched arm. The anterior labrum tears, a Bankart lesion (see Image) occurs and the shoulder dislocates. Some shoulders may spontaneously reduce, however, on many occassions, a trip to your local Emergency Room is needed to reduce the shoulder or put the shoulder back into place.
Why did my shoulder dislocate?
In most traumatic dislocations, a labral tear has occurred. The labrum or the ligaments on the front of the shoulder, tear and allow the ball of the shoulder joint to jump over the edge of the socket and remain in that position until reduced. The most common form of instability of the shoulder involves trauma, a labral tear and a Bankart lesion.
In cases where the ligament has stretched over time, usually due to stress of pitching, swimming or overhead sports, the ligaments are simply not able to prevent the shoulder from moving forward and dislocating. In this situation, the ligaments are not torn, they are simply not tight enough.
In patients over the age of 50, a common cause of instability or a shoulder dislocation is a massive rotator cuff tear. This typically follows trauma, but instead of tearing the ligaments or the labrum in the shoulder, all the supporting muscles tear and the shoulder slides out of place. Most dislocations in patients over 50 should be evaluated with and Ultrasound or MRI to determine the integrity of the rotator cuff muscles.
Labrum Tears and Instability: What are some of the issues to consider?
By far the most significant issue in shoulder instability (associated with a labral tear) is the issue of recurrence... or re-dislocation. The younger you are when you first dislocate, the higher the risk of recurrent shoulder dislocations. Some studies have shown the recurrence rate can be as high as 50-75% in patients under 21 years of age. This occurs because they have a labral tear, which does not heal back to its normal positon, and the ligaments are loose because the labrum is not in its proper position.
In traumatic shoulder dislocations there is a risk of nerve or vessel inury. These are relatively rare, but it can cause temporary numbness or tingling in the arm. This occurs because the top of the humerus will hit the nerves in front of the shoulder when it dislocates.
How are labral tears and shoulder dislocations initially treated?
By far, the most common treatment is a sling until you feel better. It is controversial whether or not the sling helps you “heal” your labral tear or diminishes the risk of re-dislocation. The number one issue you need to be concerned about following a shoulder dislocation is whether or not the shoulder is going to dislocate again. The risk of having more dislocations is related to your age at the time of your first dislocation. The younger you are (under 30), the higher the risk is that you will go on to dislocate over and over again.
The treatment for a shoulder which continues to dislocate is an arthroscopic repair of the labrum where we actually sew or stitch the labrum back to the front of the shoulder.
When is shoulder instability surgery necessary?
Do all labral tears require surgery?
In patients with traumatic instability associated with a labral tear, surgery is indicated in cases where recurrence (additional dislocations) are documented, and a labral tear, or a ligament tear is present. The number of recurrent dislocations can influence the success rate of the surgery. Everytime your shoulder redislocates, you are stretching the ligaments further. During the surgery, which is usually an arthroscopic procedure, the labral tear is reduced back to its normal position and held in place by a number of sutures or stitches as demonstrated in the video referenced above.
In patients with atraumatic or multi-directional instability, surgery is only indicated after documented failure of a proper, lengthy physical therapy program. Many patients in this group will not require surgery.
In older patients whose instability is due to a massive rotator cuff tear, urgent surgery is usually indicated to repair the rotator cuff. This maximizes your chances for a successful repair since the rotator cuff can retract and undergo degenerative changes (atrophy) with time — making a delayed repair difficult, if not impossible.
What are the risks of shoulder surgery?
The risks of surgery, in general, include the risk of infection, recurrent instability (no surgery is 100% successful), nerve injuries, stiffness, loose or migrating hardware, and loss of motion.
What is the success rate of shoulder instability surgery:
In cases of traumatic unidirectional instability, the success of an arthroscopic reconstruction is between 88-92%. The success rate diminishes if you have had many dislocations.
In cases where you ligament simply stretched and you failed to improve with physical therapy, the results of surgery are less impressive than in the traumatic group. Success rates of 55-85% are quoted in the literature — and the success truly depends on the type or direction of the instability you have or whether or not your ligaments are *normal*.
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What is the best treatment for your Shoulder Dislocation condition?
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