Shoulder Joint Arthritis
Arthritis is the loss of the cartilage lining of the joint surface (articular surface). Normally this is a soft, glistening, smooth, white tissue, which acts as a bearing surface to allow the joint to move freely. If the cartilage is damaged the surface becomes rough and no longer glides. This causes pain and stiffness within the joint.
What are the causes?
Osteoarthritis: Less common in the shoulder than in the hip and knee. It may be genetic (inherited) or may be due to heavy manual work but a specific cause is usually not found.
Rheumatoid Arthritis: This condition affects joint and organs throughout the body.
Trauma: If the shoulder joint has been broken (fractured) at some point the cartilage may have been damaged.
Instability: If the shoulder has dislocated a number of times, the cartilage may have been damaged with each dislocation.
What are the symptoms?
Pain is usually the first complaint. It is often felt deep in the shoulder and may be difficult to locate precisely. The shoulder may feel stiff and weak. There may also be a sensation of grinding or catching within the shoulder. On occasion there may be an audible crunching.
How is the diagnosis made?
The doctor will listen to the description of the symptoms and will examine the shoulder. Plain x-rays are performed as a first port of call and are usually sufficient to make the diagnosis. If there is a concern that there may be more than arthritis in the shoulder (i.e. a rotator cuff tear), then further investigations will be performed.
What is the initial treatment?
There is no cure for arthritis. If the cause is rheumatoid arthritis, then a rheumatologist will be involved to optimize the medications to control the condition. If one of the other causes is responsible then initial treatment consists of painkillers and anti-inflammatories, exercises to strengthen the rotator cuff and exercise modification (avoiding the things that hurt).
If the initial treatment does not work, what is next?
A Corticosteroid injection into the shoulder can give pain relief. The amount of benefit is variable as is the duration, which may be as little as days or as long as months.
Arthroscopy and debridement in which an arthroscope is introduced into the shoulder and the rough cartilage is smoothed down also has variable results with benefits as variable as those seen with injection although usually longer lasting.
Shoulder replacement in which the arthritic shoulder joint is replaced with a new one of metal and plastic give relief of pain in 90% of patients. The replacements last on average 15 years.