Shoulder Joint Replacement surgery has been performed for about 60-70 years. Initially, it was done to replace the shoulder joint in cases of humeral head fractures, but later it has been increasingly used to treat shoulder osteoarthritis.
Although the number of shoulder joint replacement surgeries is less than knee and hip replacements, the quality and design of shoulder prostheses, as well as surgical techniques, have been developed. This has expanded the use of shoulder joint replacement surgery to treat various conditions. Moreover, shoulder joint replacement surgery effectively reduces pain and improves shoulder function, allowing patients to better return to daily activities.
The shoulder joint consists of 3 bones
- The humerus, whose upper end is a round ball-shaped head
- The scapula, which has a socket-like surface to accommodate the round head of the humerus
- The clavicle
The parts of the shoulder joint at the humeral head and socket are covered with cartilage, which is smooth and slippery to reduce friction during movement. Both the humeral head and socket are held together or covered by the joint capsule, muscles, and surrounding tendons, which provide stability to the shoulder joint. These structures are essential for the shoulder’s wide range of motion, making it the most mobile joint in the body.
‘Shoulder joint replacement surgery’ refers to removing the damaged or worn joint surface and replacing it with a prosthetic material, which may involve replacing only the humeral head or both the humeral head and socket.
Causes of diseases requiring shoulder joint replacement surgery
- Osteoarthritis of the shoulder, which can result from 4 conditions
- Degenerative Osteoarthritis
This condition involves the degeneration of the cartilage surface due to aging and use, mostly found in patients over 60 years old, and is the most common cause for shoulder joint replacement surgery.
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- Inflammatory Osteoarthritis
Various inflammatory arthritis conditions cause chronic inflammation of the joint capsule, thickening of the capsule, and adhesion to the cartilage surface, leading to cartilage degeneration and osteoarthritis. The most common inflammatory arthritis causing shoulder osteoarthritis is rheumatoid arthritis.
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- Traumatic Osteoarthritis
Patients may have shoulder injuries such as fractures or collapse of the cartilage surface, or recurrent shoulder dislocations, which accelerate the development of osteoarthritis.
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- Rotator Cuff Arthropathy
When the rotator cuff tendons are severely torn for a long time, the humeral head moves upward and is no longer centered in the socket, causing friction with the upper edge of the socket during movement. Additionally, when the joint capsule and tendons are torn, the joint fluid leaks out, accelerating cartilage degeneration. This type of osteoarthritis involves pathology in both the shoulder joint and rotator cuff tendons, so shoulder joint replacement surgery in these patients requires more detailed treatment than in other groups.
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- Severe Humeral Head Fracture
In cases where the humeral head is severely fractured into multiple pieces making metal fixation unsuitable, fractures with a risk of avascular necrosis, fractures in elderly patients, or those with osteoporosis, these factors are considered for treatment by shoulder joint replacement surgery instead of metal fixation.
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- Humeral Head Avascular Necrosis
Some conditions cause impaired blood supply to the humeral head, leading to bone death and collapse, resulting in subsequent joint degeneration. Reduced blood supply may be seen in patients on long-term steroid use, fractures at the humeral head, prolonged deep diving, chronic heavy alcohol consumption, etc. Osteoarthritis from this cause can be effectively treated with shoulder joint replacement surgery.
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- Failed Shoulder Surgery
Additionally, shoulder joint replacement surgery is an option for failed shoulder surgeries such as Failed Massive Rotator Cuff Repair, Failed Resection Arthroplasty, Failed Glenohumeral Arthrodesis, etc.
What are the symptoms in patients with the above conditions that should be considered for shoulder joint replacement surgery?
- Severe shoulder pain that interferes with daily activities, such as pain when reaching for objects, dressing, bathing, or pain even at rest, such as at night causing insomnia
- Frozen shoulder with limited movement to the extent that the arm cannot be used in daily life
- Weak shoulder muscles with inability to lift the arm
- Failure of conservative treatments including medication, injections, physical therapy, and non-prosthetic conservative surgery
