What Is Shoulder Arthritis?

Introduction

Arthritis is the general term used for a group of diseases that cause inflammation and pain in the joints. There are different types of arthritis affecting various parts of the body including: osteoarthritis, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, reactive arthritis, and gout. While these types all share similarities, each is very different and could be covered in an article of their own. However, for this article, we will be focusing on types of arthritis affecting the shoulder. 

The shoulder is one of the most mobile joints in your body, its structure permitting a wide range of movement in multiple directions. It is comprised of two joints formed by several bones. The glenohumeral joint is formed by the rounded head of the humerus (the upper arm bone), articulating with the glenoid socket of the scapula (shoulder blade). The acromioclavicular joint is formed between the tip of a process which comes up and over from the back of the shoulder blade to the front of the body and the outer end of the clavicle (collarbone). This is the only bony attachment of the arm to the rest of the body via the breastbone (sternum). The other attachments are formed by muscles, and the stability of the shoulder is largely produced by a cuff-like ring of muscles called the ‘rotator cuff’, which also keeps the arm bone head (humeral head) centred in the shallow glenoid socket. 

The shoulder is a type of joint called a ball-and-socket joint, but the shallowness of the socket allows a wide range of motion at the expense of stability.²

Arthritis, as mentioned earlier, involves inflammation and pain in the joint(s). In a healthy joint, there is a layer of smooth cartilage that covers the ends of the bones, allowing them to move smoothly without friction. In arthritis, this cartilage becomes increasingly damaged, resulting in pain, stiffness, and reduced joint mobility. These are the most common symptoms of arthritis in general.⁶

So, when we talk about ‘shoulder arthritis’, we are referring to arthritic conditions where the shoulder glenohumeral joint's cartilage deteriorates, causing pain, discomfort, reduced movement and ultimately loss of function.

Types of shoulder arthritis

There are several types of shoulder arthritis, but the two most common are osteoarthritis and rheumatoid arthritis.

Osteoarthritis

Osteoarthritis (OA), the most common type of arthritis, occurs when the cartilage and other tissues within the joint break down after developing a change in their structure. 

Cartilage is a smooth protective connective tissue which forms a thin (approximately 3mm) covering over the bone surfaces that move together within the joint. In an analogous manner to Teflon, it greatly reduces the friction between the surfaces. A lubricating fluid (synovial fluid) is also secreted by the synovial layer, which nourishes the cartilage and further reduces friction, creating smooth movement.

Contrary to popular belief, cartilage breakdown is not due to simple ‘wear and tear’ of the joint – rather, a disease process produces changes within the cartilage or other tissue, setting off the breakdown, which generally degenerates slowly with time. It is not known what actually triggers the changes.

In the shoulder, this can develop as a result of ageing, abnormal joint structure, a genetic defect in the cartilage, previous injuries, and excessive or abnormal use of the joint. As the protective cartilage in the shoulder joint is damaged and breaks down, the bones may eventually rub against each other, causing pain, stiffness and a grinding sensation (crepitus) during movement.^1,6

Rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, which means that the body's immune system mistakenly attacks its own tissues. Unlike osteoarthritis, RA directly affects the synovial membrane, which lines the joint capsule that surrounds the joint surfaces and produces synovial fluid. This can lead to inflammation in the shoulder joint and cause pain and damage over time.⁷

In most cases, shoulder pain and inflammation due to RA tend to happen in the later stages of the disease and in people who are older when they develop RA. 

Rheumatoid arthritis has also been linked to other shoulder conditions because of the chronic inflammation involved. These include rotator cuff degeneration and tears, frozen shoulder syndrome, and bursitis.⁷

Causes of shoulder arthritis

Various risk factors can contribute to the onset of shoulder arthritis, such as age, previous injuries, overuse of the joint, genetics, and, in the case of RA, autoimmune diseases. 

As people get older, the risk of developing arthritis increases because the cartilage becomes more vulnerable to damage. ⁶ Changes triggered in the structure of the shoulder joint cartilage can lead to the progressive deterioration of cartilage with age and the onset of arthritis. This is estimated to affect one-third of people aged 60 years and older.³

Previous injuries to the shoulder, such as fractures of the bones in the shoulder joint or dislocations, can increase the likelihood of developing shoulder arthritis later in life. Damage to the joint can disrupt the normal functioning of the shoulder, shoulder socket and the surrounding area, accelerating cartilage degeneration.⁶

Overuse of the joint by people such as athletes and manual workers can also result in shoulder arthritis over time. Repeated and excessive use of the shoulder joint, especially in activities that involve lifting heavy objects or repetitive overhead motions, are contributing factors to the development of shoulder arthritis.^2,6,8

Genetics are also thought to play a role in this. Some individuals may be genetically predisposed to rheumatoid arthritis. If you have a family history of rheumatoid arthritis, you may have an increased risk of developing it yourself.^5,6

Autoimmune conditions like rheumatoid arthritis and lupus can increase the risk of developing arthritis in multiple joints, including the shoulder. These conditions are a result of the body's immune system mistakenly attacking its own tissues and damaging the shoulder joint in the process.⁷

Symptoms of shoulder arthritis

Symptoms of shoulder arthritis may seem similar to those symptoms in other areas of the body affected by arthritis. Also, some other musculoskeletal conditions affecting the shoulder can present with similar symptoms. These can include pain in various parts of your shoulder, stiffness or limited shoulder movement, a grinding sensation (crepitus) with movement, and weakness in the shoulder. These symptoms are usually worse at night and with any activity that requires the arms to be lifted over head height. They include:

• Shoulder Pain: persistent pain in the shoulder joint, particularly when you move your arm or lift objects, is a hallmark symptom of shoulder arthritis^{2, 3}
• Stiffness: you may experience stiffness in your shoulder, making it difficult to move your arm freely. This symptom may be more prominent in the early hours of the day after waking up 
• Limited range of motion: arthritis can restrict the range of motion in your shoulder, sometimes making it challenging to perform everyday activities such as reaching overhead, reaching behind your back or even holding and using household items^2,6,8
• Swelling and tenderness: inflammation of the shoulder joint can lead to swelling and tenderness around the affected area. This is especially common in rheumatoid arthritis of the shoulder, which might also include a ‘hot to touch’ feeling in the area⁷
• Crepitus: some people with shoulder arthritis may notice a crackling or grinding sensation in their shoulder when they move it. This is called crepitus and is caused by the bones rubbing against each other due to cartilage loss²
• Weakness: Muscle weakness in the shoulder can develop as a result of arthritis, further limiting your ability to use the joint effectively^3,6

It's important to note that the severity and progression of symptoms can vary markedly from person to person. 

Diagnosing shoulder arthritis

Diagnosis of shoulder arthritis will typically involve combining information from medical history, physical examination, and imaging tests. Upon your visit, your healthcare provider will start by asking you about your symptoms, including when they started, how they have progressed, and any relevant medical history, such as previous injuries or a family history of arthritis. This will be followed by a physical examination of your shoulder joint. They will assess your range of motion, check for swelling and tenderness, and listen for crepitus during movement.^2,3,6,7

To confirm the diagnosis and assess the extent of cartilage damage, your doctor may order imaging tests. X-rays and CT scans can show changes in the joint space and the presence of bone spurs or osteophytes, while MRI (magnetic resonance imaging) can provide a detailed view of soft tissues such as cartilage, tendons, and the synovium.^{2, 6, 7}

Treatment options for shoulder arthritis

The good news is shoulder arthritis has a lot of treatment options, all of which aim to improve your quality of life. The choice from a range of treatments with varying degrees of invasiveness depends on the severity of your symptoms and the extent of the joint damage. However, they can be classified into three kinds of management – conservative, surgical and alternative options:

Conservative treatments

• Physical Therapy:  a physical therapist (physiotherapist) can design a customised exercise program to strengthen the muscles around the shoulder joint. This will aim to improve joint stability and range of motion and reduce pain.
• Medications: nonsteroidal anti-inflammatory drugs (NSAIDs) can help relieve pain and reduce inflammation, which are the hallmark symptoms of arthritis. In some cases, periodic corticosteroid injections into the joint may also be recommended to provide short-term relief for a few months ^2,6
• Lifestyle Modifications: Avoiding activities that worsen symptoms and sometimes using assistive devices or braces may help manage pain and reduce strain on the shoulder joint ^2,6

Surgical treatments

• Arthroscopy: Arthroscopic surgery is a minimally invasive procedure that allows doctors to examine or treat the interior of a joint through small incisions, also known as keyhole incisions, using an instrument called an arthroscope. If there is minimal joint damage, arthroscopic surgery can be used to remove damaged tissue, bone spurs, or loose bodies from the joint. This approach often leads to shorter recovery times compared to open surgery, making it a preferred choice for many joint-related issues^{6, 7}
• Shoulder replacement: for more advanced cases of shoulder arthritis, a surgical procedure known as shoulder replacement may be recommended. In this surgery, the damaged parts of the shoulder bones are removed and replaced with prosthetic implants. The implants, usually made of metal and plastic, mimic the natural structure of the shoulder^{6, 7}
• Resurfacing: in some cases, rather than replacing the entire joint, only the damaged part of the joint is resurfaced with a prosthetic component ^{6, 7}

Complementary therapies

• Acupuncture: some people find relief from arthritic pain through acupuncture, which involves the insertion of thin needles into specific points on the body 
• Heat and cold therapy: applying heat or cold packs to the affected area can help alleviate pain and reduce inflammation
• Supplements: glucosamine and chondroitin sulphate supplements are sometimes used to support joint health, although their effectiveness is still a subject of debate  
• Chiropractic care: The American Arthritis Foundation notes that studies in mainstream medical journals are increasingly showing the benefits of chiropractic care for low back and joint pain, which applies a variety of modalities rather than just manipulation. Like the NHS, it also advises observing certain precautions when sourcing chiropractic care and then only from a registered practitioner.

FAQs

Can shoulder arthritis be prevented?

While it may not always be possible to prevent shoulder arthritis, there are steps you can take to reduce your risk. Maintaining a healthy weight, avoiding overuse of the shoulder joint, and protecting yourself from injuries are good preventive measures. Additionally, staying active and performing exercises that strengthen the muscles around the shoulder can help maintain a healthy joint.^1,2,6

Is shoulder arthritis only seen in older adults?

No, shoulder arthritis can affect people of all ages, although it is more common in older adults. However, younger individuals can develop shoulder arthritis as a result of injuries or genetic predisposition.^1,2,4,7

How is shoulder arthritis different from other types of arthritis?

Shoulder arthritis specifically affects the shoulder joint, whereas other types of arthritis, like rheumatoid arthritis, can affect multiple joints throughout the body. Each type of arthritis may have distinct causes and treatment approaches.^1-4,6

Can I still use my shoulder if I have arthritis?

Yes, you can still use your shoulder, even if you have arthritis. In fact, it's important to stay active to maintain joint mobility and muscle strength. Your healthcare provider or physiotherapist can recommend exercises and ‘occupational’ modifications to help you use your shoulder effectively while managing pain and discomfort.^2,3

Is surgery the only treatment option for shoulder arthritis?

No, surgery is not the only treatment option for shoulder arthritis. Many individuals find relief from non-surgical treatments such as physical therapy, medications, and lifestyle modifications. The choice of treatment depends on the severity of your symptoms and the extent of joint damage.^2,6,7

Can shoulder arthritis get worse over time?

Yes, shoulder arthritis can progress over time if left untreated. Without intervention, the cartilage in the shoulder joint may continue to deteriorate, leading to increased pain and functional limitations. Seeking early diagnosis and appropriate treatment can help slow down or manage the progression of the condition.^2,3

How long is the recovery time after shoulder replacement surgery?

Recovery time after shoulder replacement surgery varies depending on the individual and the type of procedure performed. Generally, it can take several weeks to several months to regain full strength and range of motion. Your surgeon and physiotherapist will provide guidance on post-operative care and rehabilitation.

Are there any long-term complications of shoulder arthritis?

Untreated or poorly managed shoulder arthritis can lead to long-term complications such as chronic pain, muscle weakness, and restrictions in daily activities. In severe cases, it can affect the overall quality of life. However, with proper treatment and lifestyle adjustments, these complications can often be minimised.

Summary

The shoulder consists of multiple bones and operates as a shallow ball-and-socket joint, allowing for an extensive range of motion. In cases of shoulder arthritis, the protective cartilage within the joint deteriorates, leading to discomfort and pain.

The two most prevalent types of shoulder arthritis are osteoarthritis and rheumatoid arthritis. Osteoarthritis is often a result of ageing, prior injuries, or excessive joint use, where the protective cartilage breaks down, causing bones to rub against each other. Rheumatoid arthritis is an autoimmune disease which impacts the synovium and induces inflammation within the shoulder joint, ultimately affecting the range of motion and muscle strength. Notably, it can lead to additional complications such as rotator cuff degeneration, frozen shoulder syndrome, and bursitis.

Symptoms, ranging from pain and stiffness to weakness and limited range of motion, can vary in severity and progression among individuals.

A wide array of treatment options is available for shoulder arthritis, including physiotherapy, medication, surgery, and complementary therapies, all aimed at enhancing one's quality of life. 

Prevention strategies involve maintaining a healthy weight, avoiding overuse, and protecting against injuries while remaining active is crucial for preserving joint mobility and muscle strength.