Editor's Note: Dr. Boyd Hoddinott (aka, "doch") came to me with this idea, and it's a solid one. Boyd has a BSc, M.D., CCFP, and MPH, and has 45 years of experience in sports medicine at the local, university and international levels of skiing, track & field, hockey, football, off-ice training and wrestling. Originally born in Parry Sound, Ontario, he now is part of Maple Leaf Family and Sports Medicine here in Ohio. This first article came to pass based on discussions of Ryan Murray's injury back in the fall of 2012. I have edited the article for flow only; all original content is from Dr. Hoddinott. --DP
There are two joints in the shoulder: the glenohumeral, and the acromicoclavicular ("ac"). Though I have seen far more ac than glenohumeral joint injuries in hockey players, most of these "separations" (as they are commonly called) limit activity because of pain, not function. An ac joint separation in a shoulder for an athlete who is a "thrower", however, is obviously very problematic.
So, the term "separated shoulder" gets used a lot, but there are some distinctions to be made. The ac joint "separates", whereas the glenohumeral joint "dislocates". If the hip joint has a deep socket, picture the shallow glenohumeral ball and socket as a "basketball on a plate". This anatomy allows for an amazing range of movement (compare your shoulder to any other joint in your body) but this necessitates a natural degree of instability. To help stabilize this joint, the ball of the humerus is held by a cartilaginous band attached to the outside edge of the socket (the "labrum"). This labrum has the consistency of your ear cartilage and grips the head of the humerus (upper arm bone).
In addition to this structure, the shoulder joint is also held in place is by a series of muscles, which include the six rotator cuff tendons as well as the pectorals, latisimus and deltoid muscles. If these tendons become stretched or partially torn, or the muscles are weakened by nerve pressure, then the protection of the joint suffers.
The second image for you to picture is the six rotator cuff tendons (muscles) coming off the shoulder blade and body like strings on a puppet that work in concert to stabilize the ball in the socket as the humerus moves through its wide range. As we age, these tendons fray to the point that 30% of shoulders in normal 40 year olds have partial tears (often without symptoms).
In the young athlete, however, when the shoulder dislocates, the labrum is almost always torn and will not heal properly without surgery--the "Bankart procedure"--or some variation with sutures and staples. The surgery is usually very successful (see Brassard, Derrick: both shoulders) but may have to be delayed if the nerve is stretched and muscles subsequently weakened. Though I have no direct knowledge, my reading from reports of Ryan Murray’s injury is that his junior coach kept playing him after the first dislocation and he suffered further dislocations. This stretched the axillary nerve that supplies the deltoid muscle. Thus, his surgery was delayed from November until January to allow the nerve to recover. This circumstance makes for a much longer rehab. We cannot blame Columbus medical staff or trainers for this, and I wonder if management was informed about the initial dislocation.
Obviously, the joint can dislocate in any direction. Due to the strength of young athletes and the forces applied, more of these are anterior (front) or inferior (under), though I have seen most every direction. Rebuilding the muscles after the post-operative healing period of a couple of months takes a long time, and is critical to protect against future dislocations.
I hope this article gives you a better understanding of shoulder injuries in the young athlete. Go Jackets!
--Dr. Boyd C. Hoddinott