SHOULDER

Shoulder Arthritis

The shoulder is made up of three bones, upper arm bone (humerus), shoulder blade (scapula) and collarbone (clavicle). A combination of muscles and tendons keeps your humerus centred in its shoulder socket. These are called the rotator cuff. There are two joints in the shoulder, both may be affected by arthritis. One joint is located where the clavicle and top of the shoulder blade (acromion) meet, known as the acromioclavicular (AC) joint. The other is where the head of the humerus fits into the scapular, called the glenohumeral joint.

The most common forms of arthritis affecting the shoulder include:

Osteoarthritis
Both surfaces of the joints in the shoulder are covered with articular cartilage which provide a smooth cushion and allow pain free, frictionless movement of the joint. Degeneration of the cartilage results in osteoarthritis. As the articular cartilage wears away, the surfaces become frayed and rough, and the protective joint space between the bones decreases. During movement the bones of the joint rub against each other causing ‘bone on bone’ pain. Osteoarthritis is the most common type of arthritis which often occurs with advanced age, excessive strain or another disease, injury or deformity.

Rheumatoid arthritis

Rheumatoid arthritis is an auto-immune disease meaning the defences that protect the body from infection instead damage normal tissue (such as cartilage and ligaments) and soften bone. The joints of the body are covered with lining called synovium which lubricates the joint and makes it easier to move. Rheumatoid arthritis causes the lining to swell leading to pain and stiffness in the joint. Rheumatoid arthritis affects multiple joints in the body, mainly hands and feet) and tends to be symmetrical (affects the same joint on both sides of the body).

Symptoms

Each form of arthritis affects the shoulder differently, however pain is the most common symptom of shoulder arthritis, is aggravated by activity and progressively gets worse over time. The location of pain will vary depending on which shoulder joint is affected:

Glenohumeral joint pain is centred in the side or back of the shoulder and may intensify with changes in the weather. Ache deep in the joint is a common complaint.
Acromioclavicular (AC) joint pain is focused on the top of the shoulder and can sometimes radiate to the side of the neck
Rheumatoid arthritis pain may be throughout the shoulder if both glenohumeral and AC joints are affected.

Other symptoms include limited range of motion, early morning stiffness, swelling and redness. Bone spurs or excessive bone can also build up around the edges of the joint.

Causes

Damage of the cartilage in the shoulder joint can cause shoulder arthritis. When the cartilage is damaged, the raw bones begin to painfully rub against each other leading to inflammation. The proportion of cartilage damage and inflammation varies on the type and stage of the arthritis. Osteoarthritis is caused by a decrease of cartilage in the joint which may be due to excessive strain over prolonged periods of time, other joint diseases, injury or deformity however is commonly associated with ageing and general joint degeneration.

Rheumatoid arthritis is often caused when the genes responsible for the disease are triggered by infection or any environmental factors. With this trigger the body produces antibodies (the defence mechanism of the body) against the joint and may cause rheumatoid arthritis.

There are numerous other conditions that can cause arthritis and often the exact cause is not known. These include:

Growth abnormalities of the shoulder
Trauma (fracture)
Increased stress on the joint for example overuse, excessive weight.
Avascular necrosis (loss of blood supply) caused by high dose steroid use, heavy alcohol consumption, sickle cell disease, trauma injury (shoulder fracture)
Infection
Growth abnormalities of the shoulder
Connective tissue disorders
Inactive lifestyle e.g. obesity; inflammation e.g. Rheumatoid arthritis

Diagnosis

Diagnosis is made by medical consultation and examination, taking the patient's past medical history and confirmed by X-ray of the shoulder. Sometimes an MRI and/or CT scan may be offered, this can help determine whether pain is being impacted by other areas of the shoulder.

Treatment Options

Once damage has been done to the cartilage and tissues within the hip, unfortunately it is irreversible and there is no ‘cure’ for arthritis. Rather it is about managing your symptoms in the initial stages and progressing to more definitive treatment as your symptoms progress and as dictated by medical professionals.

Non Operative Treatment

As with other arthritic conditions, your GP or medical physician would probably start you on the most common non-operative treatment including pain killers (paracetamol or panadol osteo) and anti-inflammatories if tolerated and not contraindicated. It can also be helpful to manage your arthritis by activity modification i.e. limiting pain provoking activity and physical therapy exercises to improve range of motion, strength and function of the shoulder. Icing your shoulder for 20 to 30 minutes two or three times per day can also help to reduce inflammation and ease pain.

Injections can sometimes be helpful to reduce pain if surgery is not indicated.

Surgery

Following consultation and review, if arthritis has progressed and other interventions have not succeeded, surgical intervention for treatment may be recommended. As with all surgeries, it comes with some risks and should be left as a last resort.

Shoulder Arthroscopy

In some cases shoulder arthroscopy may be an option to debride (clean out) the inside of the joint, diagnose and treat other issues in the shoulder. Shoulder arthroscopy provides pain relief however will not eliminate arthritis from the joint.

Find out more about Shoulder Arthroscopy.

Shoulder Replacement

Advanced arthritis can be treated with shoulder replacement surgery where the damaged and diseased portions of the bone and cartilage are surgically removed and replaced. Replacement surgery options include:

Total Shoulder Replacement (Left) - where both the head of the humerus and glenoid are replaced. A plastic cup is fitted into the glenoid and the metal ball is attached to the top of the humerus.
Reverse Total Shoulder Replacement (Right)- in a reverse shoulder replacement, the socket and metal ball are opposite to a total shoulder replacement. The metal ball is fixed to the glenoid and the plastic cup is fixed to the upper end of the humerus. Reverse total shoulder replacement works better for people with cuff tear arthropathy as it relies on different muscles, not the rotator cuff, to move the arm.