Glenohumeral Joint Osteoarthritis

What is shoulder osteoarthritis?

What are the causes of shoulder arthritis?

What is shoulder osteoarthritis?

Osteoarthritis (OA) of the shoulder refers to the wear and tear changes that can affect the joint cartilage, similar to other joints in our body.

The shoulder joint (the glenohumeral joint) is a ball and socket type joint. The ball is formed by the humeral head (the upper end of the arm bone), and the socket is formed by the glenoid, part of the shoulder blade that articulates with the humerus. Both the ball and socket are covered by “cartilage”. This protective layer lines the joints in our body to ensure smooth and frictionless joint movement. In Shoulder osteoarthritis, the cartilage will get thinner and, over time, might get completely disrupted. This progressive and degenerative process is referred to as “osteoarthritis”.

The shoulder (glenohumeral joint) differs from another small joint called the acromioclavicular (AC) joint. The latter is higher up, located between the collar bone (clavicle) and a part of the shoulder blade called the acromion. This joint can also be affected by osteoarthritis. The glenohumeral and AC joints are important for normal shoulder function and movements.

What are the causes of shoulder arthritis?

The shoulder joint is less affected by arthritis than the weight-bearing joints within the body (knee and hip). Some of the factors that can predispose to shoulder osteoarthritis:

- Age: Shoulder osteoarthritis is more common in people over 50.

- Trauma: Previous shoulder fracture or dislocation can predispose to osteoarthritis, particularly if the fracture involves the joint surface. This is referred to as “post-traumatic osteoarthritis.”

- Developmental factors: Some shoulders have slightly altered development (for example, shallow socket). Such factors can affect joint stability and predispose to osteoarthritis

- Other factors like increased BMI and family history of arthritis

What are the clinical features of shoulder arthritis?

The symptoms depend mainly on the degree of arthritis. They include

- Dull and deep ache within the shoulder joint.

Occasionally, the pain might get worse and feels sharp due to active inflammation.

- If arthritis progresses, the pain will worsen, limiting usual activities and sleep. It will also lead to a reduction in the range of movement, especially overhead activities.

- Feeling of grinding when trying to move the shoulder. This is called crepitus and happens because of the loss of cartilage, resulting in the bones rubbing against each other.

What other conditions can present similar to shoulder osteoarthritis?

Symptoms of shoulder arthritis can be similar to a few other conditions, such as:

Shoulder osteoarthritis vs frozen shoulder

One difference would be the age group in which these two conditions prevail. Shoulder arthritis is more common in people over 60 years, whereas frozen shoulder is more common in younger groups, mainly affecting people between 40-60 years. However, if there has been a previous shoulder injury, shoulder arthritis can be seen at a younger age.

Both conditions can lead to restriction in shoulder movement; however, in arthritis, the reduction in movement is most noticeable early morning and might be eased slightly after activity. In frozen shoulder, the movement that involves moving the arm to the outside (termed external rotation and shown in the picture below) is most affected. Finally, a shoulder X-ray would be very useful for the diagnosis. In osteoarthritis, it will show the arthritic changes and confirm the diagnosis. In Frozen shoulder, the X-rays are usually normal.

Shoulder arthritis vs. Acromioclavicular (AC) joint osteoarthritis.

The AC joint is higher between the collar bone and the shoulder. So, AC joint arthritis pain is usually felt at the end of your collar bone just underneath the skin at the top of your shoulder. It is mainly aggravated by overhead activities. To find out more, please see our article about AC joint arthritis.

How to diagnose shoulder osteoarthritis?

The diagnosis of shoulder osteoarthritis is usually suspected clinically based on the clinical features and examination findings and confirmed with imaging. A shoulder X-ray is usually the first imaging test performed. It is very good in assessing arthritis changes within the joint. An x-ray will show a reduction or loss of the joint space with bony changes depending on the severity of the arthritis. Blood tests might also be arranged. These are mainly done to rule out a different type of arthritis that can affect joints (called inflammatory arthritis). These are different from osteoarthritis. Rheumatoid arthritis is an example of inflammatory arthritis.

Although a shoulder X-ray is an excellent examination to assess the shoulder joint for osteoarthritis, it provides a limited assessment of the soft tissues. Therefore, it cannot assess if there is significant active inflammation (called synovitis) in the lining of the shoulder joint. Therefore, we perform further shoulder imaging, like ultrasound or MRI, if there is a discrepancy between the clinical and x-ray findings. An ultrasound examination would be very useful, particularly when there is concern regarding other shoulder problems like sub-acromial bursitis and rotator cuff disease, as these conditions can be accurately assessed on ultrasound. Furthermore, ultrasound is very useful to guide injection therapy in the shoulder.

What is the treatment for shoulder osteoarthritis?

Many patients respond very well to conservative management, especially if the arthritis is mild. These include:

Physiotherapy. This aims to increase the range of shoulder movements using a dedicated exercise program and increase strength in the shoulder muscles.
Anti-inflammatory tablets (like ibuprofen) and creams (like voltarol gel).
Activity modifications and avoiding certain movements that can aggravate the arthritis

Can a steroid injection help with shoulder arthritis?

If the above measures are not helping and your shoulder pain is severe, affecting your daily activities, exercises and sleep, then there is a role of an ultrasound-guided cortisone injection into the shoulder joint. Injecting under ultrasound guidance is very useful as it allows for live visualisation of the needle to ensure accurate injection into the shoulder joint. Ultrasound guidance results in more accurate, less painful and faster procedures. Unlike ultrasound sound, an X-ray can also be used to guide injections into the shoulder joint, .

How does steroid injection help with shoulder arthritis?

Corticosteroid (cortisone) is a potent anti-inflammatory medicine routinely used to manage inflammatory conditions (like bursitis, arthritis and tendinosis). They are commonly used in managing shoulder arthritis and frozen shoulder to reduce inflammation and allow the patient to manage the condition, usually by undergoing physiotherapy and strengthening the shoulder muscles. To find out more, please read our article about ultrasound-guided shoulder steroid injection

Ultrasound guided shoulder joint steroid injection

What are the medicines injected in a shoulder steroid/cortisone injection?

The commonly used type of steroid injection for subacromial bursa injection is triamcinolone acetonide (Kenalog). This is a long-acting preparation that normally takes a few days to start working. Current evidence suggests that cortisone can improve pain and function for up to 3 months, but in some cases, it can last longer. The injections usually also contain a local anaesthetic that provides immediate pain relief lasting a few hours. The steroid injection may take up to 2 weeks to reach its full therapeutic effect.

Can intra-articular Hyaluronic acid injection help with shoulder arthritis?

Hyaluronic acid is a naturally occurring substance within our bodies/joints and is increasingly being recognised as an effective treatment option for osteoarthritis (mainly the mild and moderate form of the disease). Evidence shows that intra-articular Hyaluronic acid injections have anti-inflammatory and analgesic effects, in addition to joint lubrication and shock absorbent properties. Therefore, it can be used in the management of shoulder arthritis and we use this in our practice as an alternative to cortisone injections. To find out more about intra-articular Hyaluronic acid injections, please see our article.