Total Shoulder Replacement

Introduction

The shoulder has a greater range of motion than any other joint in our body, but because it can perform so many movements, the shoulder is vulnerable to stress, injury, and arthritis. Arthritis is a major cause of shoulder pain.

Arthritis is a common disease that causes joint pain, stiffness, and swelling. It affects the cartilage in joints.  Cartilage is a very tough, shock absorbing material that covers the ends of many of our bones.  The cartilage forms a smooth surface and allows the bones in our joints to glide easily during motion.  Arthritis can cause the cartilage to wear away. Loss of the protective lining can cause painful bone on bone rubbing.

Severe shoulder arthritis can be quite painful and can cause restriction of motion.  While the symptoms of shoulder arthritis may be tolerated with some medications and lifestyle adjustments, there may come a time when surgical treatment is necessary.  Shoulder replacement surgery, also called Arthroplasty, involves the replacement of the damaged bone and cartilage with metal and plastic implants.  Shoulder Arthroplasty is a treatment option that can relieve pain and restore function.  Very often, people tolerate their symptoms for long periods of time because the arm is not a weight bearing extremity.  For this reason, arthritis of the shoulder is not as common as in the hip and knee.  As such, most people know someone who has had a hip or knee replacement, but many people do not even know that shoulder replacement is an option.

Anatomy

Our shoulder is composed of three bones.  The humerus is our upper arm bone.  The clavicle is what we call our collarbone.  The scapula is the shoulder blade that moves on our back.  A part of the scapula, called the acromion, forms the top of the shoulder.  There are a total of four joints in our shoulder complex.  The humerus and the scapula form the main shoulder joint, the glenohumeral joint.

The glenohumeral joint is not a true ball-in-socket joint like the hip, but it is similar in structure.  The top of the humerus is round like a ball.  It rotates in a shallow basin, called the glenoid, on the scapula.  A group of ligaments, called the joint capsule, hold the ball of the humerus in position.  Ligaments are strong tissues that provide stability. In other words, the joint capsule is responsible for holding our arm in place on our body.

Several ligaments connect our shoulder bones together.  Tendons attach our muscles to our bones. Our muscles move our bones by pulling on our tendons.  They move our arms to position our hands for a variety of functions.  The shoulder also provides stability when our elbow flexes as we lift objects.

The Rotator Cuff tendons connect strong muscles to the humerus bone.  These muscles allow the arm to rotate and move upward to the front, back, and side.  A fluid-filled sac, called the subacromial bursa, lubricates the rotator cuff tendons allowing us to perform smooth and painless motions.  We use the rotator cuff muscles to perform overhead motions, such as lifting up our arms to put on a shirt, comb our hair, or reach for an item on a top grocery shelf.  These motions are used repeatedly during sports, such as pitching in baseball, serving in tennis, and passing in football.

Causes

Arthritis is a major cause of pain, stiffness, and swelling in the shoulder.  Arthritis can occur for many reasons, including aging, “wear and tear,” injury, autoimmune disease, and inflammatory disease.  There are over 100 different types of arthritis. Osteoarthritis, Post-Traumatic Arthritis, and Rheumatoid Arthritis are types of arthritis that frequently develop in the shoulder.

Osteoarthritis is the most common type of arthritis affecting some 21 million Americans alone.  It tends to develop as people grow older.  Osteoarthritis can result from overuse of a joint during sports or work.  Post-Traumatic Arthritis can develop in individuals of all ages after a shoulder injury, such as a fracture.

Osteoarthritis causes the cartilage covering the end of the bones to gradually wear away resulting in painful bone on bone rubbing.  Abnormal bone growths, called spurs, can grow in the joint. The bone spurs add to the pain and swelling, while disrupting movement.

Rheumatoid Arthritis is one of the most serious and disabling types of arthritis.  Rheumatoid Arthritis can affect people of all ages, but most frequently occurs in women and those over the age of 30.  It is a long-lasting autoimmune disease that causes the synovium to be inflamed and painful.  It also causes joint swelling and deterioration.  Tissues surrounding the joint may also become affected. Pain, stiffness, and swelling are usually ongoing symptoms, even during rest.

Some people that have had a rotator cuff injury for a long time may develop Rotator Cuff Tear Arthropathy.  This condition results from the changes in the shoulder joint that occur because of the rotator cuff tear.  Eventually, arthritis can develop, which leads to destruction of the joint cartilage.

Shoulder Replacement Surgery is also a treatment for Avascular Necrosis.  This medical condition causes a lack of blood flow to the head of the humerus bone, causing it to die.  Avascular Necrosis can be caused by several factors, including chronic steroid use, deep sea diving, severe fractures, sickle cell disease, and heavy alcohol consumption.

Symptoms

A deep ache is the primary symptom of shoulder arthritis. In the early stages of arthritis, your shoulder pain may get worse with movement or activity.  As time goes on, your shoulder pain may become continuous, even when you are resting.  It may be severe enough to keep you awake at night and interrupts the ability to do everyday tasks such as putting on a belt or carrying groceries. Inflammation can cause your shoulder joint to also feel swollen and stiff.

Arthritis can make your joints feel weak or unstable.  Your shoulder may feel like it “grinds” or “catches” when you raise your arm.  You may have difficulty moving your arm.  This can make it challenging to complete common activities, such as putting on your shirt or washing your hair.

Diagnosis

Your doctor can diagnose arthritis by conducting a physical examination.  You will be asked about your symptoms and level of pain.  You may be asked to perform simple arm and shoulder movements to help your doctor assess your muscle strength, joint motion, and joint stability.  Blood tests and other laboratory tests may identify what type of arthritis you have.

Your physician will order X-rays to see the condition of your shoulder bones and to identify areas of arthritis or bone spurs.  Sometimes your doctor may order Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI) scans to get a better view of the bone and soft tissue structures.  These imaging tests are also painless.  They require that you remain very still while a camera takes images of your shoulder joint.  CT scans provide a view in layers like the slices that make up a loaf of bread.  MRI scans provide the most detailed images of the tendons and ligaments.

Treatment

Some cases of shoulder arthritis can be treated with non-surgical methods including pain relief and rest.  Over-the-counter medication or prescription medication may be used to reduce pain and swelling.  If your symptoms do not improve significantly with these medications, your doctor may inject your joint with corticosteroid medication.  Corticosteroid medication is a relatively safe pain reliever.

Occupational or physical therapists can help you strengthen the muscles surrounding your shoulder joint.  Your therapists may also apply heat treatments to help ease your pain and stiffness.  They may recommend ways for you to do your daily activities, such as housework and meal preparation, in a manner that puts less stress on your joints.

Surgery

Shoulder Arthroplasty is recommended when non-surgical treatments have provided minimal or no improvement of your symptoms.  The goal of Shoulder Arthroplasty is to relieve pain and restore shoulder mobility.  The surgery is performed as an inpatient procedure, and you may expect to stay in the hospital a day or two following your surgery.  You will either require general anesthesia or a regional nerve block for the procedure.  There are a few different types of shoulder replacement surgeries.

Total Shoulder Replacement Surgery is recommended for people with bone-on-bone Osteoarthritis and intact rotator cuff tendons.  This is the most common type of shoulder replacement surgery.  Your surgeon will make an incision, approximately six inches long, on the front of your shoulder joint.  Your surgeon will replace the damaged head of the humerus with a highly polished metal ball.  The metal ball may be surgically implanted in the humerus or attached with surgical cement, depending on the condition of the bone.  The glenoid is replaced with a plastic socket.

In some cases, the surgeon may only replace the head of the humerus in a procedure called a Hemiarthroplasty.  This procedure is used if the glenoid cartilage is in good condition.

A Hemiarthroplasty is commonly used to treat shoulder fractures.

A Reverse Total Shoulder Replacement Surgery is recommended for people with completely torn rotator cuffs, severe arthritis with cuff tear arthropathy, or prior failed shoulder surgery. Traditional total shoulder replacement would still leave these individuals with pain and the inability to lift their arms above their shoulders. In a Reverse Total Shoulder Replacement Surgery, the ball and the socket are switched. The metal ball is attached to the scapula, and the socket is attached to the end of the humerus. This allows the deltoid muscles, instead of the damaged rotator cuff muscles, to lift the arm above the shoulder.

Another form of replacement is resurfacing Arthroplasty when the cartilage is removed from the humeral head and a metal "cap-like" prosthesis is placed over it.

Recovery

Your shoulder will need several months to fully recover from the surgery.  Your surgeon will restrict your arm movements for a short period of time following your procedure.  You will wear an arm sling for some period of time after surgery.  An occupational or physical therapist will help you gently move your arm starting on the first day following your surgery, or on the day of surgery.

Generally, Shoulder Arthroplasty rehabilitation takes from three to six months.  You will gradually work to strengthen and increase the movement in your shoulder.  Your recovery time will depend on the extent of your condition and the amount of surgery that you had.  Your surgeon will let you know what to expect.  Overall, most people achieve good results with shoulder replacement surgery.  They experience an improved quality of life because of decreased pain and improved function.