It took three surgeons before they could finally diagnose my shoulder with a humeral avulsion of the glenohumeral ligament. I guess they call this an HAGL injury. Even with X-rays and MRIs, they never found the problem until my first surgery didn't work and they went in a second time. Is this typical with these kinds of shoulder injuries? I'm just wondering...
A quick review of HAGL injuries might help other readers researching this question. The word humeral tell us the shoulder is involved because the humerus is your upper arm bone. At the top of the humerus is the round ball that fits into your shoulder socket and makes all those circular arm movements possible. Avulsion of tendons or ligaments means there has been a tearing of the soft tissues -- enough to pull away from the bone where it was attached.
The glenohumeral ligament is a band of tissue around the shoulder that provides the stability needed to keep the head of the humerus in the socket. Age-related degeneration and trauma (injuries) that damage this ligament can result in a chronically dislocating shoulder.
Recognizing that a patient has a humeral avulsion of glenohumeral ligaments (HAGL) is a key to successful treatment of shoulder instability. In many cases, a patient with a shoulder that frequently pops out of the joint has more than one type of damage to the soft tissue structures. If the HAGL lesion goes undetected, surgery to treat other problems may not be successful. This is not uncommon and sounds like what happened to you.
How does the surgeon diagnose the problem? There are several steps in the diagnostic process. First, the surgeon asks the patient all about how this happened, what the symptoms are, and what makes it better or worse. A very important piece of patient history is a prior failed shoulder surgery.
HAGL tears occur most often when the person has the arm in a position of abduction (away from the body) and external rotation (outward rotation). Think of a pitcher's arm after the wind-up and just before releasing the ball or how you would hold your hand under your head when lying on the ground looking up at the stars. Force or trauma with the arm and hand in this position cause avulsion injuries of the soft tissues leading to dislocation.
Clinical tests are carried out to give the surgeon an idea of the joint motion and muscle strength (or weakness). The surgeon will challenge the shoulder in different positions and directions. These tests are called provocative maneuvers.
This step helps identify which muscles, tendons, and ligaments might be affected. The direction of instability is determined through these tests. The shoulder can have multidirectional instability meaning it is unstable (dislocates) in more than one direction -- forward, backward, upward, and/or downward.
X-rays and other imaging studies such as MRI may be done. These tests give the surgeon a look inside to see what is going on. But for humeral avulsion injuries of the glenohumeral ligaments, magnetic resonance arthrography or MRA (dye injected into the joint before the MRI) is really essential.
An even better diagnostic test is the arthroscopic exam where the surgeon inserts a long, thin needle into the joint. There's a tiny TV camera at the end of the scope that gives an inside view of the joint. The surgeon can see where the ligament attaches and look for any places along the rim of the socket or front and back of the joint capsule where the soft tissue has pulled away from the bone.
Humeral avulsion of glenohumeral ligaments (HAGL) can go undetected when the torn edge of the ligament scars down to the joint capsule. The area of damage isn't easily seen because it is hidden underneath the subscapularis muscle. If this lesion isn't discovered and repaired, the shoulder will remain unstable. Repeated dislocations even after surgery to correct some other problem (e.g., torn labrum, avulsion of tendon, rotator cuff tears) is an indication of an HAGL lesion.
Michael S. George, MD, et al. Humeral Avulsion of Glenohumeral Ligaments. In Journal of the American Academy of Orthopaedic Surgeons. March 2011. Vol. 19. No. 2. Pp. 127-133.
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