Last Updated: Friday" January 28 2005
The AMBRII and TUBS syndromes represent clearly defined clinical pathologic entities each of which has specific diagnostic features and treatment strategies. Together they constitute the great majority of patients who present with glenohumeral instability. Patients who do not fit into one of these two categories have highly individualized problems and cannot be grouped effectively together. In evaluating these patients a meticulous history and physical examination take on even greater importance.
Examination and tests
When there has been an initiating injury it is essential to determine the position of the arm and the direction and magnitude of the force producing the injury so that the likelihood of a capsular tear can be determined. Unless this is clearly the case the default assumption is that the shoulder has become dysfunctional without a substantial anatomic lesion and therefore needs to be managed with a rehabilitative approach emphasizing strength balance endurance and good technique.
Unless a functionally significant instability can be determined on history and physical examination the emphasis on rehabilitation must continue. When the history and physical examination do not indicate the nature of the functional instability "studies" such as contrast CT MRI examination under anesthesia and arthroscopy are unlikely to be helpful in determining the treatment. "Findings" on these tests such as "increased translation a large axillary pouch or labral fraying" may be identified even in functionally normal shoulders and as such may have no relation to the patient's functional problem. The risk therefore is that findings on these tests may distract the clinician from findings on history and physical examination. Unless the functional instability can be rigorously characterized by the history and physical examination it is unlikely that surgical treatment will be curative.
The history and physical examination constitute the most efficient and cost effective mechanisms for identifying treatable problems of glenohumeral instability. When these clinical tools do not clearly define the nature of the patient's functional problem management by techniques other than physical rehabilitation and activity modification are unlikely to be effective. Using this approach the need for expensive diagnostic approaches in cases of suspected instability is reduced to a minimum and surgery is reserved for those who can most benefit from it. This highly selective approach improves the overall results of surgical treatment of instability by helping to avoid the situation where a well-done operation fails to restore the patient's function.