What is Traumatic Anterior Shoulder Instability (TUBS)?


The shoulder is the most movable joint in the body because of the range of motion performed by it. This also makes it the most unstable joint and vulnerable to injuries. 

Traumatic anterior shoulder instability is a very common condition having a high recurrence rate in young people. It is more likely to happen to males before the age of 30. 


The shoulder comprises of the humerus, scapula, and clavicle. The movements occurring in the shoulder are controlled by the actions of the glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic joints. The ligaments and muscle structures around the glenohumeral help in creating balanced joint reactions. If the unity of these structured is disrupted it can lead to atraumatic or traumatic instability. 90% of the dislocations occur in the anterior part of the shoulder. 


Causes of Traumatic Anterior Shoulder Instability 


Traumatic anterior shoulder instability (TUBS) occurs due to a large external force enough to injure the important joint structures. Typically, traumatic instability can be a result of a sporting accident or fall on the outstretched hand. The instability is often in the anteroinferior direction. 


Symptoms of Traumatic Anterior Shoulder Instability 


  • Severe pain and stiffness in the anterior region of the shoulder
  • Continuous feeling of discomfort even when performing minimal movements
  • Limited ROM and weakness in the shoulder 
  • Inability in lifting heavier objects and difficulty in lowering the arm
  • Clicking sound when moving or lifting the arm


Although the symptoms vary from patient to patient, these are the common symptoms that a patient may suffer. 


Diagnosis of Traumatic Anterior Shoulder Instability 


Evaluating patients with TUBS can be a complicated process thus doctors need to obtain a comprehensive history of the patients. Details regarding the traumatic event including the arm position are necessary to come to a clear diagnosis. 


The doctor will carry out a physical examination to check for symptoms and signs that can determine the severity of the pain and will also look for stiffness and flexibility in the shoulder.


The most common direction of traumatic instability is anteroinferior. The doctor will check for stability by keeping the patient’s hands under the back of the shoulder acting as the fulcrum for external rotation and force. The doctor will then apply extension and external rotation loads in different positions of elevation to challenge various parts of the anterior mechanism. If the patient limits the range of motion actively, the doctor will proceed to hold that position for 1 or 2 minutes to fatigue the stabilizing muscles. When the muscles tire out, the mechanism holding the humeral head in the glenoid will feel as if it moving out of the joint. This examination will strongly support the diagnosis of traumatic anterior instability. 


The physical examination will be followed by X-rays and MRI scans. X-rays help in showing the clear image of the bones and the displacement caused due to instability.

MRI scans can be advised as the next step as they will show the damage caused to the ligaments and muscle structures around the joints. 


The doctor may also conduct necessary tests to come to a clear conclusion and rule out other shoulder related problems. These tests include:


  1. Kinetic Medial Rotation Test: A test used to differentiate between anterior shoulder pain symptoms that could be instability or impingement.
  2. Surprise/Release Test: This test helps in indicating pain when the shoulder is placed in a position of abduction, ninety-degree elbow flexion, or maximum external rotation.
  3. Rowe Test: A shoulder examination that indicates anterior instability. A positive result or increased motion can mean glenohumeral instability, while pain may mean rotator cuff ligament or tendon damage. 


After consultation and coming to a diagnosis, the doctor will select the method of treatment to be followed. 


Treatment for Traumatic Anterior Shoulder Instability 


Treatment for Traumatic Anterior Shoulder Instability ranges from nonsurgical methods to surgical methods depending on the severity of the problem.


Nonsurgical methods include: 

  • Rest: Rest plays an important role in speeding up the healing process. Activities that put pressure on the anterior region of the shoulder should be avoided
  • Ice packs: applying ice packs on the affected areas two or three times a day will help in reducing the pain and lessen the swelling providing temporary relief.
  • Medication: pain killers or muscle relaxants as prescribed by the doctor are very effective and help in reducing the pain.
  • Physical therapy: physical therapy performed under the supervision of trained professionals yields good results. Therapy should include range of motion exercises as well as stretching and strengthening exercises.  


If nonsurgical treatments fail the doctor may advise surgical treatments. Several studies have indicated favourable results for surgical stabilization of the shoulder after a traumatic injury. 


Treatment should be decided considering the patient’s health and lifestyle.