Background and Etiology
The shoulder complex is composed of three osseous joints and one articulation, with stability provided by muscles, ligaments, the glenoid labrum and joint capsule. The glenohumeral joint of the shoulder is a ball and socket joint between the head of the humerus or the upper arm bone (ball) and the glenoid fossa of the scapula (socket) or shoulder blade.
The bony joint surfaces of the head of the humerus and the glenoid fossa are covered with articular cartilage. The articular cartilage has a smooth and shiny surface that allows the ends of the bones to slide freely over each other. This is what enables the joint to move smoothly.
Arthritis is described as the wearing, degeneration, or loss of articular cartilage in a joint. The three most common types of joint arthritis are osteoarthritis, rheumatoid arthritis, and traumatic arthritis. However, a specific type of arthritis, called glenohumeral arthritis, affects the shoulder joint. These different types of arthritis, in addition to severe fractures, can damage the shoulder joint so much that it functions very poorly. In these cases, a shoulder replacement may be necessary.
The most common conditions that lead to a shoulder replacement are glenohumeral arthritis, osteoarthritis, Rheumatoid Arthritis, traumatic arthritis, and severe fractures.
Glenohumeral Arthritis is also known as shoulder arthritis. It is a gradual wearing and degeneration of the joint surfaces or articular cartilage in the glenohumeral joint. Glenohumeral Arthritis is a common source of shoulder pain in older individuals, affecting as much as 20% of the older population. It can affect young people, though this is less common. This type of arthritis is also less common than arthritis in the hips, knees, or hands.
Osteoarthritis is a gradual wearing down and degeneration of the joint surfaces or articular cartilage. Osteoarthritis is most common in people who are middle age or adults over the age of 50.
Unlike other forms of arthritis, rheumatoid arthritis is a systemic autoimmune disease that is not caused by common wear and tear on the joint. This condition usually affects joints symmetrically (for example, both shoulders). Rheumatoid arthritis causes degeneration of the articular or joint cartilage. It can also affect the tissue that surrounds and lubricates the joint (synovium). If the joint surfaces and cartilage are not lubricated they can start to rub, causing the wear that leads to arthritis pain.
Rheumatoid arthritis can affect other parts of the body including organs like the heart and lungs, and can even cause fatigue. The cause of Rheumatoid arthritis is not fully known. It is considered an autoimmune disease where the cells of the body attack themselves. Although it is a chronic condition, individuals can have periods with little to no symptoms mixed with acute or symptomatic periods. There can be a genetic component to this disease. In the case of severe rheumatoid arthritis of the glenohumeral joint may be a shoulder replacement may be indicated.
Traumatic arthritis occurs as a result of blunt, penetrating, or repeated trauma to a joint. Damage to the articular cartilage can occur when extreme force or pressure is exerted on a joint, causing the cartilage to tear or break off into small pieces. These pieces can become lodged in the joint, where they will rub against the other joint structures. This trauma can make the joint weak, causing the inflammation and pain associated with arthritis.
A fracture is defined as a partial or complete crack in a bone. Fractures can be severe with complete displacement of the two ends of the bone that requires surgery to realign. Fractures of the shoulder are usually caused by direct trauma or a fall on outstretched hand (FOOSH). The shoulder is comprised of three bones: the humerus, scapula (shoulder blade) and clavicle (collar bone). In the case of severe glenohumeral fractures a shoulder replacement may be indicated.
Symptoms of an arthritic shoulder joint
- Severe pain and aching in the shoulder
- Loss of range of motion of the shoulder
- Swelling around the joint
- Increased size or visible deformity of the joint
- Weakness that makes daily activities, particularly those that require lifting or over the head motion difficult
- A sensation of “cracking” or “crunching” in the shoulder joint
- Stiffness, that can be extreme, causing tremendous difficulty moving the joint
A shoulder replacement is a surgical procedure. A shoulder can be resurfaced, or the joint can be completely removed and replaced with artificial material.
This surgical procedure is an alternative to total shoulder replacement. Younger individuals tend to be good candidates for this procedure. It involves the placement of a cap over the head of the humerus and the use of a metal cup in the glenoid (socket) of the scapula ( shoulder blade) . There is less bone loss required in this procedure and the risk of dislocation is reduced. It is recommended for patients who do not have large bone loss, rheumatoid arthritis or osteoarthritis.
Total Shoulder Replacement
Total shoulder replacement may be indicated in severe cases of glenohumeral arthritis, osteoarthritis, rheumatoid arthritis or traumatic arthritis secondary to a fracture. Patients who have intact rotator cuff tendons tend to be good candidates for a total shoulder replacement.
There are several different designs for shoulder replacements but all have two components: the ball made of highly polished strong metal or ceramic and the socket, a durable cup made of plastic, metal, or ceramic material. Cement may or may not be used to stabilize the prosthesis on the existing bone.
Physical Therapy Interventions
Physical Therapists are professionals, educated and trained to administer interventions. As defined by The Guide to Physical Therapist Practice, interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis and the patient or client’s goals.
Following joint replacement surgery, a well planned out rehabilitation program of physical therapy interventions will be essential to the success of a shoulder replacement. Following the procedure there will be a period of immobilization with restrictions on movement and function. The physical therapy and rehabilitation program will be focused on regaining range of motion, strength, stability and proper function of the shoulder complex. Common Physical Therapy interventions in the treatment of post surgical shoulder replacement include:
- Manual Therapeutic Technique (MTT): Hands on care including soft tissue massage, stretching and joint mobilization by a physical therapist to improve alignment, mobility and range of motion of the shoulder. Use of mobilization techniques also help to modulate pain.
- Therapeutic Exercises (TE) including stretching and strengthening exercises to regain range of motion and strengthen muscles of the shoulder and upper extremity to support, stabilize and decrease the stresses place on the shoulder joint.
- Neuromuscular Reeducation (NMR) to restore stability, retrain the upper extremity, and improve movement techniques and mechanics (for example, reaching, over head activities and lifting) of the involved upper extremity.
- Modalities including the use of ultrasound, electrical stimulation, ice, cold, laser and others to decrease pain and inflammation of the involved joint.
Following surgery, it is important that the patient returns to full activity gradually. Instruction in daily activities and a comprehensive home program are helpful for regaining strength and range of motion in the shoulder as the surrounding tissues work with the new artificial joint to control the arm. Patients do well following shoulder replacement as there is a reduction in pain, improvement in motion and one can return to most daily activities. Many patients return to sports such as golf, swimming, and bowling. Minimizing the stress on the shoulder joint will extend the longevity of the shoulder replacement.