Patient Education

There is no other joint in creation like the human shoulder.  A hip joint resembles a trailer hitch and the knee is a rotating gliding hinge, but the shoulder is like a golf ball on a tee that is turned sideways!  The shoulder is very complex and can perform wonderful functions, from throwing a baseball 100mph to bench pressing 300lbs to climbing a sheer rock wall to holding a toddler overhead.

The shoulder is stabilized both passively and actively.  The labrum (Latin for ‘lip’) is a fibrous ring that deepens the socket and also provides attachment for the shoulder capsular ligaments as a means of passive stabilization.  There are 18 muscles around the shoulder joint that provide power and compressive forces that pull the humeral head (the golf ball) into the glenoid (the tee).  The amazing thing is that the shoulder is stable through an arc of 180 degrees or more in most planes.

In my practice, the most common problems are, in order:

1. Rotator cuff tears
2. Shoulder osteoarthritis
3. Adhesive capsulitis (frozen shoulder)
4. Shoulder instability
5. Acromioclavicular joint arthritis and separations
6. Isolated bursitis without rotator cuff tear
7. Shoulder pain referred from the neck

I will discuss each of the problems below.

There are 4 deep muscle tendon units that are interwoven to some degree and their collective job is to take the torque out of the shoulder to keep the humeral head centeredon the glenoid and also to compress the joint to provide stability.  These 4 deep muscle tendon units are collectively called the rotator cuff.  Tears most commonly occur in the tendon near the bony attachment on the humerus (upper arm bone).  See the illustration at the left.

Again, in my practice, the most common causes of cuff tears are 1. A fall onto the shoulder or arm, 2. Repeated overuse (like being a mechanic or swimmer), 3. Being yanked by a dog on a leash, 4. No identifiable cause.  It is amazing that up to 40% of people will have some degree of cuff tear in their life.

The articular cartilage that lines our joints is truly incredible.  It is made up of multiple layers and is rigidly fixed to the underlying bone.  Loss of articular cartilage manifests as OSTEOARTHRITIS; the xray hallmarks are joint space narrowing, spurring and cysts in the bone (like a pothole in the street).  Many people I see with normal xrays have been told by another doctor that they have “arthritis” in the shoulder joint, but more often than not, that turns out to be not true.  True osteoarthritis can be treated conservatively with activity modification, injections of steroid medication, occasionally arthroscopic debridement of loose particles and inflamed tissue and perhaps (not yet proven scientifically) stem cells.  The greatest gains in shoulder surgery in the past 15 years have been in shoulder replacement prosthesis design and in surgical technique.

For people who have osteoarthritis and a functional rotator cuff, the surgical treatment is anatomic total shoulder replacement. This technique replaces the ball of the humeral head with a metallic ball, secured by a stem inside the humeral shaft and a high molecular weight polyethylene new surface on the glenoid.

If the rotator cuff is badly diseased or irreparably torn, a reverse total shoulder replacement is utilized, fixing the ball on the glenoid to provide a fulcrum for the high molecular weight polyethylene tray placed on the humeral side (hence then name reverse since the ball is placed on the glenoid instead of the humerus).  Tremendous advances have been made in this technology since the FDA approved it in November of 2003.  I placed my first reverse total shoulder replacements in April 2004 and have performed more than 1300 of these operations since, as of November 2018.

If it is unclear, after thorough exam and diagnostic studies, as to the integrity of the cuff, I can make an intraoperative decision as to which design will work better, since I can place either prosthesis through the same 3 inch minimally invasive incision.

Frozen shoulder is one of the most painful problems a person can have with their shoulder.  In most cases, there is no known reason that it started, but the problem rather quickly results in painful loss of motion.  The lining of the joint becomes intensely inflamed and leads to motion loss, most notably in reaching to the side and reaching behind.  While the cause isn’t known, about 75% of people who get frozen shoulder are women, often with some recent hormonal fluctuations, especially associated with menopause.  About 20% of people presenting with frozen shoulder are men, but they have often had a recent trauma that jarred the shoulder, probably causing some bleeding into the joint that led to the inflammation.  The other group of people prone to develop frozen shoulder are diabetics, possibly because of some degree of neuropathy.

The following arthroscopic photographs from the Boston Shoulder Institute show the difference between the normal appearance of the shoulder on the left and someone with frozen shoulder on the right.

Quite often, if I can evaluate someone within 3 months onset of frozen shoulder, I can reverse the problem with injections of corticosteroids into the shoulder joint and into the subacromial bursa outside the shoulder, followed by 2-3 weeks of physical therapy.  It is important for people to understand that frozen shoulder is a self-limited problem, but that it can take 12-18 months to resolve spontaneously, which is a long time to be miserable with a stiff painful shoulder.  Rarely, arthroscopic treatment to remove the inflamed tissue and release the contracted capsule are needed for successful resolution in a timely manner.

COMMON SHOULDER INSTABILITY PATTERNS

This problem is very common in athletes, especially overhead and collision/contact athletes.  The variations of shoulder instability are too great to discuss here exhaustively, but are described as resulting from either a complete dislocation or a partial dislocation (also known as subluxation) or an overuse instability (such as from pitching a baseball). They are described in terms of the direction of instability and progression of the problem, often leading to being unstable in multiple directions as more episodes of instability occur.  Many involve tears of the labrum, the location of which is usually determined by the position of the arm at the time of injury.

While almost all rotator cuff tears have an associated subacromial bursitis, the bursa can become inflammed without the cuff being torn.  This often happens with overuse or even with sleeping in an abnormal position.  The diagnosis is often made from just the history and several physical exam findings; usually, the rotator cuff is strong, but the shoulder is clearly irritated despite normal or near normal motion.  Treatment is only very rarely surgical; an injection into the area with corticosteroid and a very brief course of physical therapy will ususally solve the problem.   If not, MRI is used to rule out an associated rotator cuff tear.

Many of the nerves that come the spinal cord in the neck have branches that send fibers to the shoulder; irritation of these nerves, because of the way nerves work (often causing a phenomenom called referred pain) can cause shoulder pain when the problem exists elsewhere.  For instance, you have probably heard of people who are having a heart attack who report having pain in the left arm; this is an example of referred pain.  Referred pain occurs because the limb buds of the embryo develop into arms and legs, pulling the nerves along as the buds grow; the referred pain happens in patterns in part determined by whatever other structures developed in the limb bud or even in the precursors to the bud in the long axis of the spine (like the heart or esophagus).  Also, most of the shoulder nerves come from the 5^th and 6^th cervical nerve roots, which are the levels most commonly effected by ruptured discs or pinched nerves.  A good history and exam are very helpful in sorting out the problem.  MRI is extremely helpful as well, as can be nerve conduction studies.

I am so glad you asked.  The rotator interval is the part of the shoulder that consists of the front part of the supraspinatus cuff tendon, the biceps long head’s exit point from the shoulder, and the upper 1/3 of the subscapularis front cuff tendon, all of which are covered by the insertion site for a structure called the coracohumeral ligament.  This area is where most cuff tears start and symptoms often present with biceps long head pain, often down to the elbow.  Tears start here because we live our lives with our shoulders forward and to the side, whether working out with weights or using our computer’s mouse.  This area also is the most complicated area of the shoulder with a pulley to hold the biceps in place, as well as having the insertion of the two cuff tendons in a very small space.  It has become very popular to cut the biceps tendon long head and reattach it lower down the arm, but I do not subscribe to that approach.  My preference, with a normal biceps long head tendon, is to repair the pulley and subscapularis.

The following are a photos from inside a left shoulder and a drawing of the same area from outside a left shoulder.

Tears in this area of the shoulder are very common and failure of this problem to have been addressed with prior surgery is by far the most frequent source of post operative discomfort I see when giving second opinions.