Arthritis - Gleno-humeral joint arthritis
X-ray showing degenerative osteoarthritic changes of the shoulder joint

Definition

Osteoarthritis or arthritis of the shoulder is a degenerative condition caused by chronic inflammation of the shoulder joints, the acromioclavicular and/or the gleno-humeral joint, which leads to severe pain and loss of function.

Erosion of the shoulder joint cartilage due to arthritis

Pathology

Osteoarthritis is a complex pathology of the joints originating from a variety of aetiologies, which have in common a persistent inflammatory process affecting multiple joint structures such as the cartilage, the connective tissue forming the synovium, the bursa and even tendons and muscles. Due to the protracted inflammation the surrounding tissues gradually degenerate and the joint space is reduced causing the opposing bones to rubbing against each other. These effects produce joint swelling, severe pain and decrease in joint mobility. 

Osteoarthritis may involve a single joint or several joints of the body and can arise suddenly or develop over years. This pathology is most frequent in women and ageing individuals. After the age of 50 most people will have a degree of joint osteoarthritis. Sadly there is no treatment to cure this disease. Due to its heterogeneity, osteoarthritis of the shoulder is divided into six main pathologies:

1. Osteoarthritis

2. Rheumatoid arthritis

3. Post-traumatic arthritis

4. Rotator cuff tear arthropathy

5. Avascular necrosis

6. Overuse

patient with severe arthritis

Causes

1. Osteoarthritis is common in older people over the age of 50 years and affects more often the acromioclavicular than the gleno-humeral joint. It results from the disruption of the cartilage tissue covering the bone extremities (acromion and clavicle), reducing the intraarticular space of the joint so that during the shoulder movement the interfacing bones touch each other, provoking pain.

2. Rheumatoid Arthritis (RA) is a chronic, autoimmune disease that involves several joints of the body simultaneously and symmetrically. It is the result of the immune system not recognising and attacking its own tissue, producing chronic inflammation with degenerative consequences for the joint. Over time RA affects the synovium, which is a thin membrane filled with fluid that lubricates the joint facilitating the movement of the humerus head. Consequently, the synovium becomes inflamed, swells, degenerates and elicits pain and shoulder stiffness.

3. Post-Traumatic Arthritis is a form of degenerative osteoarthritis that develops following an injury, such as a fracture or dislocation of the shoulder. Injuries occur in sports, motor vehicle accidents, falls or any other source of physical trauma. With damage to the cartilage and/or bone the relationship of the joint structures changes, creating a friction among its parts, which over time results in wear and tear of the joint. This rubbing is exacerbated with intensive sport or when practicing other physical activities. Excessive body weight is another factor accelerating posttraumatic arthritis due to the pressure posed on the joint.

4. Rotator Cuff Tear Arthropathy: Shoulder osteoarthritis can develop following a tear of the rotator cuff tendons. When the damaged rotator cuff is unable to stabilise the humeral head and hold it within the glenoid socket, the friction of the humeral head against the acromion will damage the surface of both bones. Over time this functional alteration sets the development of shoulder joint arthritis. When combined, a rotator cuff tear and advanced arthritis result into severe pain and inability of the patient to lift the arm.

5. Avascular Necrosis: When blood supply to the head of the humerus is impaired, the cells of the affected bone area will die, causing an avascular necrosis. This is an ongoing condition, which over time leads to a severe destruction of the shoulder joint. Initially, avascular necrosis only involves the humeral head, which eventually collapses damaging the articular cartilage and the glenoid socket. This alteration progresses into full arthritis. Avascular necrosis can be the consequence of steroid overdose, alcohol abuse, sickle cell disease and a traumatic fracture of the shoulder. When specific causes are not known, this condition is defined as idiopathic avascular necrosis.

6. Overuse: The main aetiology for the development of osteoarthritis of the shoulder joint is the overuse of the shoulder in ageing individuals and active sportsmen/women. Weightlifters, other athletes or workers who repeatedly lift heavy objects with overhead movement are vulnerable to develop in particular acromio-clavicular (AC) joint arthritis. 

Repetitive shoulder movement in construction workers can lead to arthritis

Risk factors

The incidence to acquire shoulder osteoarthritis is higher in individuals who practice certain physical professions and sports involving repetitive overhead and throwing activity (swimmers, weight lifters, tennis/racquet players) mainly due to overuse. 

Common risk factors include history of shoulder injury and fractures, surgery and systemic chronic inflammatory conditions originating from genetic autoimmune diseases such as rheumatoid arthritis, gout and psoriasis. Age and female gender, congenital bone and joint deformities, infection of the shoulder (septic arthritis), alcoholism and prolonged steroid use constitute additional risks factors for shoulder osteoarthritis.

Pain is the main symptom of shoulder arthritis

Symptoms

The symptoms arising from shoulder osteoarthritis, independent of its origin, are classically manifested with shoulder pain, which worsens as the disease progresses. In the early phase of the disease pain intensifies with shoulder movement but eventually is felt also at rest. Pain also commonly disrupts sleep quality. Pain is located in different areas depending on the type of shoulder osteoarthritis:

If the glenohumeral joint is affected, pain is felt deep in the back of the shoulder.

Osteoarthritis of the acromioclavicular joint is located on the top of the shoulder and possibly radiates towards the lateral side of the neck.

In rheumatoid arthritis pain is spread throughout the shoulder, especially if both the gleno-humeral and acromio-clavicular joints are affected.

With ongoing osteoarthritis the shoulder mobility becomes gradually restricted due to the stiffening of the joint especially when lifting the arm over the head. Other common symptoms include grinding, catching and popping noises that can be heard when moving the shoulder. As a consequence of ongoing inflammation bony growths named spurs may develop in the joint further compromising shoulder flexibility.

Medical examination of the shoulder

Diagnosis

Diagnosis is formed by firstly discussing the patient’s medical history of previous shoulder injuries and then with physical examination including special tests to determine changes in the range of movement of the shoulder and pain that may arise with function. During clinical examination the following parameters are assessed:

Inspection of the shoulder to detect structural changes to muscles, tendons and ligaments

Pain triggered in response to palpation and pressure onto the shoulder

Range of movement during passive and active motion

Production of any noises with shoulder movement

Weakness of shoulder muscle

Contribution of other joints in case of rheumatoid arthritis, gout

Primarily X-ray but also CT scan and MRI are useful diagnostic tools to detect changes in the shoulder such as joint restriction, cartilage degeneration, presence of bone spurs and associated injuries of the shoulder. These radiologic images allow to identify the nature of shoulder osteoarthritis. The diagnosis is also proven when the pain disappears after local injection of anaesthetics. If rheumatoid arthritis is suspected a blood test will confirm the disease. In case of gout or possible joint infection a small sample is aspirated from the synovium.

Treatment

Local injection of steroids in a patient with shoulder arthritis

Nonoperative treatment

Conservative treatment is the frontline for the management of shoulder osteoarthritis and includes an initial period of rest, together with application of ice/heat pads, oral administration of non-steroidal antiinflammatory drugs, (NSAIDs) and local injection of steroids when the symptoms are significant. Local hyaluronan injection seems to be effective in early arthritis having longer benefit than steroids, but involve a higher cost. In case of rheumatoid arthritis methotrexate (a disease-modifying anti-rheumatic drug with immunosuppressant activity) can be prescribed. Physical therapy is recommended to improve the range of movement and other symptoms.

Shoulder arthroscopy for debridement of an acromion spur
Shoulder hemiarthroplasty
Total shoulder replacement
Reverse total shoulder replacement

Surgical treatment

If conservative treatment for shoulder osteoarthritis is unsuccessful and the degeneration of the joint is advanced, surgery is the only option. This can be achieved via minimally invasive arthroscopic or open access surgery. Different techniques are available to repair the arthritic shoulder and vary relative to the disease conditions, use of the shoulder and age.

Arthroscopic resection arthroplasty is used to debride (remove) fragments on the inner joint to create more space and restore mobility. This procedure however will not eliminate arthritis but alleviate the symptoms temporarily. In most cases it is done arthroscopically. When the degenerative process has destroyed either the humeral head or the glenoid a prosthetic shoulder replacement is necessary. This type of surgery requires open approach and comprises a partial or total shoulder prosthesis whereby:

Humeral head resurfacing is a simplified approach of joint reconstruction. The goal of this surgery is to resect part of the humeral head, which is covered using a metal cap. This treatment is a good compromise prior to proceed with hemi or total shoulder replacement and is specifically advised in younger patients practicing sport.

Hemiarthoplasy consists in the replacement of the entire humeral head with a metal sphere and a stem inserted in the humeral shaft.

Total shoulder arthroplasty involves a complete prosthetic replacement of both the humeral head as described in hemiarthroplasty and the glenoid (socket) of the shoulder, which is substituted with a concave plastic prosthesis.

Reverse total shoulder arthroplasty is similar to the replacement of the socket and glenoid but employs a reversed ball-socket prostheses. The bio-mechanical concept is reversed and the glenoid becomes the ‘humerus head’ whereas the previous humerus head becomes the ‘glenoid’.

Resection arthroplasty is a procedure used for the treatment of arthritis of the acromio-clavicular joint. A section of the clavicle adjacent to the humeral head is resected and eventually replaced with scar tissue.

In the surgeries described a number of post-operative complications include: infections, bleeding, blood clot formation, damage of vessels and nerves, ongoing pain issues, reduced mobility and in very severe cases, ankylosis (stiffening) of the shoulder joint. Loosening and dislocation of the prosthesis may occur especially early after surgery. This may require surgery if recurrent.

A physiotherapist assists a patient with shoulder arthritis

Rehabilitation

During the post-surgery period up to 4 weeks it is advised to use a sling to support the shoulder and allow healing. Gentle physiotherapy can commence some days after the operation to strengthen the muscles around the shoulder to avoid prosthesis dislocation or loosening. This is followed by more strenuous exercise program at home for 2 to 4 months. In general following a shoulder replacement it is recommended to avoid heavy weight lifting and repetitive shoulder movements. Physiotherapy includes a number of additional measures:

Massage

Joint mobilisation

Ice/heat treatment

Physical exercise (stretching, pendular movements, shoulder shrug / squeeze, rotation)

Electrical stimulation

Education in sport and daily activities

Use of sport taping

Use of posture support

Return to sport plan

Regular exercise during aging delays the onset of shouder diseases

Prevention

Generally patients with shoulder osteoarthritis are advised to maintain an active lifestyle to keep their joint flexible and improve muscle tone to support the shoulder joint. This includes a regular exercise program, keeping weight under control, reducing overhead movements and resting when joints are painful. It is critical to modify some daily activities in order to release the pressure on the shoulder. This is achieved by reducing strenuous overhead activity and use postural taping during training.