The Basics of Multidirectional Shoulder Instability (MDI)
Multidirectional instability of the shoulder, MDI for short, refers to symptomatic instability of the shoulder and more than one direction.
Typically this involves either anterior or posterior instability based on which direction involves the most symptoms.
Activities that are repetitive such as baseball pitching, swimming, gymnastics or volleyball may lead to a gradual soft tissue elongation in young patients and resulting instability.
Along with the anterior or posterior instability, most patients have symptoms from instability of the inferior glenohumeral joint.
Multidirectional instability is more common in patients who are female and in younger athletes.
Often times patients are not able to point to a discrete incidents of trauma or a frank dislocation.
The initial symptom that patient experiences may simply be pain which may make it difficult to diagnose.
With activity however, patients may experience a dead arm, numbness and tingling in the arm, weakness or early fatigue.
On physical examination patients may have increased translation of the shoulder downwards.
Also a physical examination there are multiple tests that the orthopedic surgeon can perform to see if instability is symptomatic anteriorly or posteriorly.
Sometimes patients of multidirectional shoulder instability also have hyper laxity in general so this should be evaluated as well.
Additional diagnoses that should be looked at in patients where multidirectional instability is thought to be occurring include impingement syndrome, rotator cuff tear, thoracic outlet syndrome, biceps tendinitis, and cervical disc herniation.
MDI treatment should be centered around dedicated physical therapy.
Strengthening and endurance of the rotator cuff along with the muscles around the scapula should be the focus of this treatment.
As opposed to traumatic unidirectional instability, patient to have MBI experience much more success with physical therapy.
If the patient fails 6 to 12 months of considerable conservative treatment, surgery can then be opted for.
Successful surgery for MDI has included both open and arthroscopic techniques.
One of the procedures is called an open capsular shift procedure where the orthopedic surgeon decreases the volume of the joint to increase stability.
This procedure remains the gold standard for treatment of MDI.
However, arthroscopic surgery results have improved dramatically over the years and now rival those of the open capsular shift procedure.
The results of capsular shift procedures have shown it produces over a 90% long term shoulder stability.
The overall excellent results are just over 60% with an additional 33% having good results.
So the good to excellent surgical results approach close to 95%.
Along with a capsular shift procedure, additional considerations may include a procedure to close the rotator interval.
This is typically an add-on to an inferior capsular reconstruction when a patient has instability in that inferior direction.
Typically this involves either anterior or posterior instability based on which direction involves the most symptoms.
Activities that are repetitive such as baseball pitching, swimming, gymnastics or volleyball may lead to a gradual soft tissue elongation in young patients and resulting instability.
Along with the anterior or posterior instability, most patients have symptoms from instability of the inferior glenohumeral joint.
Multidirectional instability is more common in patients who are female and in younger athletes.
Often times patients are not able to point to a discrete incidents of trauma or a frank dislocation.
The initial symptom that patient experiences may simply be pain which may make it difficult to diagnose.
With activity however, patients may experience a dead arm, numbness and tingling in the arm, weakness or early fatigue.
On physical examination patients may have increased translation of the shoulder downwards.
Also a physical examination there are multiple tests that the orthopedic surgeon can perform to see if instability is symptomatic anteriorly or posteriorly.
Sometimes patients of multidirectional shoulder instability also have hyper laxity in general so this should be evaluated as well.
Additional diagnoses that should be looked at in patients where multidirectional instability is thought to be occurring include impingement syndrome, rotator cuff tear, thoracic outlet syndrome, biceps tendinitis, and cervical disc herniation.
MDI treatment should be centered around dedicated physical therapy.
Strengthening and endurance of the rotator cuff along with the muscles around the scapula should be the focus of this treatment.
As opposed to traumatic unidirectional instability, patient to have MBI experience much more success with physical therapy.
If the patient fails 6 to 12 months of considerable conservative treatment, surgery can then be opted for.
Successful surgery for MDI has included both open and arthroscopic techniques.
One of the procedures is called an open capsular shift procedure where the orthopedic surgeon decreases the volume of the joint to increase stability.
This procedure remains the gold standard for treatment of MDI.
However, arthroscopic surgery results have improved dramatically over the years and now rival those of the open capsular shift procedure.
The results of capsular shift procedures have shown it produces over a 90% long term shoulder stability.
The overall excellent results are just over 60% with an additional 33% having good results.
So the good to excellent surgical results approach close to 95%.
Along with a capsular shift procedure, additional considerations may include a procedure to close the rotator interval.
This is typically an add-on to an inferior capsular reconstruction when a patient has instability in that inferior direction.
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