Anterior Shoulder Instability

Anterior glenohumeral instability occurs when the shoulder dislocates or subluxes out the front of the shoulder. This may occur when if the labrum in the shoulder is injury or if the capsulolabral tissue in the front of the shoulder is stretched. In athletes instability may occur with repetitive external rotation with the arm in abduction. This is the position the arm is in when throwing a ball.

Anterior shoulder instability may occur from preceding traumatic dislocations, repetitive microtrauma with overhead activity, or generalized ligamentous laxity.

Anterior Shoulder Instability Anatomy

  • Glenohumeral stability is dependent on static (labrum, glenohumeral osseous morphology, glenohumeral capsular ligaments) and dynamic (RTC, deltoid, biceps, scapular musculature, "concavity compression") restraints.
  • Inferior glenohumeral ligament (consist of anterior inferior glenohumeral ligament, axillary pouch and posterior inferior glenohumeral ligament) is the most important for resisting anterior translation in the abducted arm.
  • The rotator cuff produces concavity-compression by creating a net force vector which directs the humeral head into the glenoid. The scapular stabilizers affect this net force by positioning the glenoid.
  • Deltoid acts as an anterior stabilizer in the abduction and externally rotated position
  • Patients with anterior shoulder instability generally have injuries to the labrum or bone (glenoid) in the front of the shoulder and also have impaired proprioception in the shoulder.

Anterior Shoulder Instability Symptoms

Patients with anterior shoulder instability typically complain of pain or instability sensations with the arm in abduction and external rotation (throwing position). Throwers note a sensation of the shoulder sliding out the front during the late cocking phase of throwing. This may be related to a "dead arm syndrome" with transient sudden, sharp pain associated with loss of ball control and numbness.

Patients who have an associated nerve injury may have weakness in the shoulder and loss of sensation around the shoulder.

Anterior Shoulder Instability Treatment

Treatment options for anterior shoulder instability include both operative and non-operative treatments. Non-operative treatment includes physical therapy focused on a strengthening program especially aimed at the dynamic glenohumeral and scapular stabilizers. Patients should also avoid provocative position for 8 weeks followed by gradually return to sport specific activities.

Operative treatment includes anterior capsular plication and/or Bankart repair. This can be done using open or arthroscopic techniques. Patients with complex instability problems may need surgery which includes bone grafting to restore stability to the shoulder.

The best treatment for any particular patient is dependent on there age, activity level and associated injuries. Young patients more frequently have recurrent instability while older patients may have an associated rotator cuff tear. Your orthopaedic surgeon will discuss all your treatment options with you and help you decide which is the best option for you.

Risks of surgery include but are not limited to: recurrent instability, chondrolysis, arthritis, fluid extravasation, Infection, Neurovascular Injury, Hardware failure, Pain unchanged or worse than before surgery, Stiffness, Incisional scar (cosmesis), CRPS, Numbness surrounding the incision, Incomplete relief of pain, Incomplete return of function, Need for further surgery, blood clots (DVT), pulmonary embolus (PE), and the Risks of anesthesia including heart attack, stroke and death. Although complications can occur they are uncommon and most patients are satisfied with their surgical outcomes. You should always discuss any concerns that you have about surgery with your surgeon and ensure that you have a surgeon that you trust and are confident in.

After surgery patients are placed into a sling for 6-8 weeks to allow the tissues the shoulder to heal. An elbow, wrist and hand range of motion program is started immediately. They are seen in the office 7-10 days after surgery to review their findings at surgery, check their incision and begin a gentle passive range of motion program for the shoulder. Range of motion and strengthening exercises are advanced over the next 6-8 weeks under the direction of a physical therapist. Eventually a sport specific therapy program is begun and patients return to full activities / sports generally at 4-6 months after surgery.

Further information about Anterior Shoulder Instability can be found at the following sites:

Every person and their particular circumstances are different so the treatment for your shoulder may be different than those discussed above. Please read this information carefully. Write down any questions that you have about your injury and its treatment and discuss them with your surgeon. Working together you and your surgeon will determine the best treatment for you.

anterior shoulder instability, shoulder instability, anterior glenohumeral instability

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