Shoulder Impingement Syndrome - Shoulder Tendonitis

Your shoulder is composed of three bones.  The humerus is your upper arm bone.  The clavicle is your collarbone.  The scapula is the shoulder blade that moves on your back.  A prominent edge of the scapula, the acromion, forms the top of the shoulder.

 

The head of the humerus is round.  It rotates in a shallow basin on the scapula called the glenoid.  A group of ligaments, called the joint capsule, hold the head of the humerus in position.  Ligaments are strong tissues that connect bones and provide stability.  In other words, the joint capsule is responsible for holding your upper arm in place at your shoulder.

 

Four muscles at the shoulder form the rotator cuff of tendon that connects to the head of the humerus.  The muscles allow the arm to rotate and move upward to the front, back, and side.  A gliding membrane, the bursa, lubricates the rotator cuff tendons and reduces friction around them when they move. 

 

You use your rotator cuff muscles whenever you perform overhead motions, such as lifting your arms up to put on a shirt or reaching for an item on a shelf.  These motions are used repeatedly during sports, such as serving in tennis, pitching in baseball, stroking in swimming, and passing in football.  Overhead motions may also be used for job duties, such as for construction.

Impingement syndrome usually occurs as a result of muscle imbalance around the shoulder that place increase stress on the rotator cuff tendons.

 

Secondary impingement syndrome results from the rubbing or pinching of the tendons and bursa during repetitive overhead movements.  Shoulder impingement syndrome occurs when the space beneath the acromion is too small for the rotator cuff tendons.  The space may be too narrow because of structural abnormalities in the shoulder bones, bone spurs, or thickened tissues. 

 

As the tendons and bursa rub together during movement, it causes friction, pain, and limited motion.  Degenerated tendons can become painful.  Tendons may develop tendonitis and the bursa may develop bursitis.  Both are painful conditions.  Continued inflammation can cause the rotator cuff tendons to tear or detach from the top of the humerus. 

Shoulder impingement syndrome causes a generalized aching pain in the shoulder and upper arm.  You may feel weakness and pain when you raise your arm for activities, such as combing your hair or putting on a shirt.  Pain at night is typical and may interfere with sleep.

Your doctor can diagnose shoulder impingement syndrome by reviewing your medical history and examining your shoulder.  X-rays are ordered to check for bone spurs or acromion abnormalities.  A magnetic resonance imaging (MRI) scan may be used to show more detailed pictures of your shoulder, particularly the rotator cuff, the muscles and joint capsule. 

Surgery is recommended when non-operative treatments have provided minimal or no improvement of your symptoms.  Surgery may be necessary to enlarge the space beneath the acromion to allow the tendons to glide freely, or to trim degenerated tendon.  This can be accomplished with surgery to remove bone spurs and the undersurface of the acromion(acromioplasty), remove some of the bursa, and occasionally a small part of the clavicle.  The surgery is typically performed arthroscopically.

 

During an open surgical repair, the surgeon makes a three or four inch incision over the shoulder to access the joint.  Arthroscopic surgery is a less invasive surgical procedure.  It uses an arthroscope and narrow surgical instruments that are inserted through small incisions.  An arthroscope contains a lens and lighting system that allow a surgeon to view inside of a joint.  The arthroscope is attached to a miniature camera.  The camera allows the surgeon to view the magnified images on a video screen or take photographs and record videotape. 

With arthroscopic technology, your surgeon will not need to open up your joint fully.  The arthroscope can be used to remove bone spurs and excess bone.  It can also be used to repair torn tissues.

Non-surgical treatments for shoulder impingement syndrome include rest from the irritating activity and ice packs or medication for pain and inflammation.  Cortisone injections are often used.  Physical therapy is very often used to regain motion and strengthen weakened muscles, thereby decreasing pain.  Physical therapists may also use modalities, such as ultrasound, to help relieve pain and stiffness.
 
If you undergo surgical treatment, your surgeon will refer you to physical therapy following your procedure.  You may initially wear an arm sling to immobilize and support your arm.  At first, a physical therapist will move and stretch your arm for you with passive range of motion exercises.  You will progress to performing arm movements independently and general strengthening exercises.  Your program will focus on achieving muscle balance for your shoulder joint.  Your exercise programs will be upgraded as you progress.  Sports specific exercises will be added, if necessary.  Eventually, your physical therapist will create a home exercise program just for you that should be continued indefinitely, as it can help prevent re-injury.

Arthroscopic surgery usually leads to less pain in the early post operative period.  It has a reduced risk of infection, less blood loss, and less pain and stiffness because only small incisions are used and less surrounding tissue is affected or exposed.  The recovery process is different for everyone, but typically it takes several months to recover from surgery with participation in rehabilitation therapy.  Your doctor will let you know what to expect.