Posterior Shoulder Instability

Lennard Funk

Most dislocations of the shoulder are anterior, but posterior dislocations and instability can occur. It may be as a result of a traumatic injury, due to excess joint laxity, abnormal bones or muscle imbalance (see more here).
The shoulder joint slips out when lifting the arm forward in the frontal plane (flexion).

One typical mechanism of injury is falling on a flexed elbow and shoulder as shown below. We have found this to be a common injury in rugby.

The structures that get injured with a posterior dislocation/subluxation include (in order of frequency):

  1. Posterior labrum - Posterior Labral Tear (reverse Bankart tear)
  2. Posterior capsule - Reverse HAGL
  3. Rotator cuff tear
  4. Bony injury - reverse bony Bankart

Investigations generally include plain x-rays, MR Arthrogram or CT Arthrogram.

Surgical repair is required for recurring instability with structural lesions as above.
For information on Atraumatic posterior instability click here

Also see Posterior Instability in the Education Section

This website is certified by Health On the Net Foundation. Click to verify. This site complies with the HONcode standard for trustworthy health information:
verify here. satisfies the INTUTE criteria for quality and has been awarded 'editor's choice'.

The material on this website is designed to support, not replace, the relationship that exists between ourselves and our patients. Full Disclaimer