What is an "engaging" Hill-Sachs injury of the shoulder? That's what the report I received from the orthopedic surgeon says is my diagnosis.
The explanation of an engaging Hill-Sachs injury may take a few steps. Let's start with a little bit of anatomy. The shoulder joint is a ball-and-socket joint. The socket is fairly shallow. This puts the joint at risk for dislocation. To help deepen the socket, the shoulder joint has a rim of cartilage called a labrum. The labrum forms a cup for the end of the arm bone (humerus) to rest and move inside.
A Bankart lesion is an injury to the labrum caused by forward (anterior) shoulder dislocation. The force of the head of the humerus (upper arm bone) as it dislocates, tears the labrum and the ligaments attached to it. The shoulder joint is unstable when the labrum is torn. There isn't anything to keep the head of the humerus from slipping forward out of the socket again. Surgery to repair the damage is usually needed.
A Hill-Sachs lesion is an injury that causes damage to the head of the humerus. It also occurs with shoulder dislocation and usually develops after the Bankart lesion occurs. When the shoulder dislocates, the smooth surface of the humerus hits against the bony edge of the socket (called the glenoid). The collision causes a dent in the bone of the humerus. This is also called an impaction fracture.
When pain occurs as the arm is rotated and moved away from the body (movements called external rotation and abduction) in someone who already has a Hill-Sachs lesion, it's referred to as an engaging Hill-Sachs lesion.
Surgery to repair the torn labrum and stop the humeral head from banging against the edge of the socket is usually very successful. Athletes are able to return to a pre-injury level of sports participation. The only concern is for recurrent shoulder dislocation; this can be prevented by repairing all aspects of damage in the shoulder. A careful and thorough orthopedic (and sometimes arthroscopic) exam is necessary to identify all soft tissue damage and bony defects requiring attention.
Francesco Franceschi, MD, et al. Remplissage Repair -- New Frontiers in the Prevention of Recurrent Shoulder Instability. A 2-Year Follow-up Comparative Study. In The American Journal of Sports Medicine. November 2012. Vol. 40. No. 11. Pp. 2462-2469.
*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.