Being the most mobile joint in the body is a huge responsibility indeed. This means that the stability of the shoulder is often the first thing that gets sacrificed when a traumatic injury occurs. Another daunting fact is that once a shoulder dislocation or instability episode happens the rate of recurrence in later years is at least 70%.

Traumatic instability (TUBS) is instability that happens from a force that is large enough to injure some of the major supporting structures of the joint like the glenohumeral capsule, ligaments, rotator cuff, or the bone of the humerus or glenoid. Anterior glenohumeral instability is the shoulder condition in which soft-tissue or bony injury allows the humeral head to subluxate or dislocate from the glenoid fossa and the joint surfaces no longer touch each other.

Traumatic anterior shoulder instability (TASI) accounts for 95% of glenohumeral dislocations so this just shows how common this type of instability is. When this takes place due to a traumatic event, the function of the shoulder most likely compromised. The patient will usually go through apprehension, recurrent subluxations, and frank dislocations. Following these mechanisms certain activities including overhead arm motions, external rotation, and, thus, physical or athletic activities will be hugely limited.

As per the Stanmore triangle of instability there are three classifications which are Traumatic structural, Atraumatic structural and the Habitual non-structural (muscle patterning or neurological changes). A traumatic instability can occur as a result of a fall on the outstretched hand during a sports activity like football, or wrestling.

A careful history and clinical examination and diagnostic X-rays are often helpful in evaluating the patient with traumatic instability. There are specifically designed physical tests for this as well like the apprehension, relocation and surprise (release) test. These tests are highly specific and strongly predictive of traumatic anterior glenohumeral instability. A fourth test, the bony apprehension test diagnose can especially help diagnose instability with a significant osseous lesion component. A detailed MRI following the tests can help reveal labrum or bony injuries of the glenoid and proximal humerus which is a condition called Hill Sachs.

Some common symptoms related to recurrent anterior instability could be glenohumeral joint pain, shoulder stiffness with difficulty warming up for the activity, rotator cuff weakness, sensation of popping, grinding or catching deep in the shoulder joint, pain when reaching backward or above shoulder height, apprehension when sleeping with the arm overhead in abduction and external rotation. The resultant neurological symptoms can be tingling or burning in the lower arm and hand or a localized numbness of the skin overlying the deltoid muscle and also tenderness of the anterior glenohumeral joint line and the posterior rotator cuff.

Depending on chronicity of symptoms, recurrence of instability, and the severity of labrum or glenoid defects, the treatment options can be operative or non-operative. Non-operative treatments include slings, bracing and physiotherapy. Operative treatment can include bony and soft-tissue reconstructions performed through open or arthroscopic approaches. Arthroscopic Bankart is the most common surgical procedure for the treatment of anterior shoulder instability. The modified Latarjet procedure have also been fairly successful in those with combined bone loss.

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Q&As on Traumatic Anterior Shoulder Instability

What is traumatic anterior shoulder instability?

Traumatic instability (TUBS) develops when a force is strong enough to harm any of the joint’s key supporting components, such as the glenohumeral capsule, ligaments, rotator cuff, or the humerus or glenoid bone, strikes the joint.

Traumatic instability often results after a fall onto an extended hand, such as in skiing, hockey, or boxing. The evaluation of the patient with traumatic instability may benefit from using X-rays and a thorough history and clinical examination.

Surgery for the injury might be considered if the instability occurs often or if the risk of recurrent dislocation usually prevents you from using your shoulder. After this procedure, postoperative care is crucial.

Why is traumatic instability also called TUBS syndrome?

Traumatic anterior shoulder instability is called TUBS syndrome because it results after a severe trauma incident, often from abduction and extension of the arm raised in the coronal plane. We refer to the typical kind of traumatic instability as the TUBS syndrome. Anteroinferiorly, the ensuing instability is often unidirectional. Typically, the Bankart lesion—an avulsion of the capsuloligamentous complex from the inferior anterior lip of the glenoid—represents the pathophysiology. Surgery to repair the ligament avulsion is usually necessary to regain function in cases with functionally severe recurrent traumatic instability. To establish this diagnosis, we have developed specific diagnostic standards.

What are the management options for traumatic anterior shoulder instability?

Only educating patients about the lesion’s existence and identifying postures and activities they should avoid may constitute the proper therapy for certain people. The shoulder’s musculature may be strengthened to prevent forcing the shoulder into unstable postures. The exercise regimen recommended for atraumatic instability may also be considered for traumatic instability. To prevent abduction, external rotation, and stretch of the shoulder, “training tape” may be placed on the anterior portion of the shoulder. Yet, many people with persistent problems may want to think about having surgery to fix the problem.

What are the symptoms of traumatic anterior shoulder instability?

The symptoms of traumatic anterior shoulder instability are:

  • Glenohumeral joint discomfort.
  • Tight shoulders make it difficult to warm up for the activity.
  • Rotator cuff insufficiency/
  • deep into the shoulder joint, there is a popping, grinding, or catching sensation.
  • suffering from back or upper shoulder pain
  • Uncertainty while sleeping with the arm up and rotating externally
  • Neurological: Localised numbness of the skin behind the deltoid muscle or tingling or burning in the lower arm and hand
  • Anterior glenohumeral joint line and posterior rotator cuff tenderness

What is the anterior drawer test?

The patient is lying on his back with his injured shoulder hanging over the exam table. There should be no tension in the patient’s arm. Place the arm in a posture that combines forward flexion, lateral rotation, and a middle abducted stance. The fingers and thumb of the stabilizing hand are placed on the scapula, securing it at the scapular spine and the coracoid. An anterior pull on the patient’s arm applies a gliding force on the glenohumeral joint. The glenoid labrum may be torn if a click is heard during the motion, or the joint may be loose enough for the humeral head to slide over the glenoid labrum rim.

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