Introduction
The shoulder is the most mobile joint in the body, allowing a wide range of movements. However, this versatility makes it susceptible to injuries, stress, and arthritis, which is a leading cause of shoulder pain.
Arthritis is a prevalent condition that leads to joint pain, stiffness, and swelling. It primarily affects the cartilage, the resilient tissue that cushions the ends of bones in joints, allowing them to glide smoothly during movement. When arthritis occurs, the cartilage can degrade, resulting in painful friction as bones rub together.
Severe shoulder arthritis can lead to significant discomfort and limited mobility. While symptoms can often be managed with medication and lifestyle changes, surgery may eventually become necessary. Shoulder replacement surgery, known as arthroplasty, replaces damaged bone and cartilage with artificial implants, providing pain relief and restoring function. Many individuals tolerate their symptoms for extended periods since the shoulder is not a weight-bearing joint. Thus, awareness of shoulder replacement options is often less common compared to hip and knee replacements.
Anatomy
The shoulder consists of three main bones: the humerus (upper arm bone), clavicle (collarbone), and scapula (shoulder blade). The acromion, part of the scapula, forms the top of the shoulder. Together, these bones create four joints within the shoulder complex, with the glenohumeral joint being the primary joint.
While the glenohumeral joint is not a typical ball-and-socket joint like the hip, it operates similarly. The rounded top of the humerus fits into a shallow socket called the glenoid on the scapula. Strong ligaments, known as the joint capsule, keep the humeral head in position, providing stability.
The shoulder's movement is facilitated by tendons that connect muscles to bones. The rotator cuff tendons attach powerful muscles to the humerus, allowing for rotation and movement in various directions. A lubricating sac called the subacromial bursa helps these tendons operate smoothly, essential for overhead activities such as lifting, sports, and daily tasks.
Causes
Shoulder arthritis can result from various factors, including aging, wear and tear, injury, autoimmune disorders, and inflammatory diseases. Over 100 types of arthritis exist, with osteoarthritis, post-traumatic arthritis, and rheumatoid arthritis being particularly common in the shoulder.
Osteoarthritis, affecting approximately 21 million Americans, often develops with age or due to joint overuse. Post-traumatic arthritis can arise after injuries like fractures.
In osteoarthritis, cartilage gradually deteriorates, leading to painful bone-on-bone contact. Bone spurs may form, exacerbating pain and swelling.
Rheumatoid arthritis is a serious autoimmune disease that inflames the synovium, causing joint deterioration and persistent symptoms such as pain and stiffness.
Chronic rotator cuff injuries may lead to rotator cuff tear arthropathy, which can progress to arthritis, damaging joint cartilage. Shoulder replacement surgery is also used for conditions like avascular necrosis, where blood flow to the humeral head is compromised.
Symptoms
A deep ache is the hallmark symptom of shoulder arthritis. In the early stages, pain may intensify with movement or activity. Over time, discomfort can become continuous, even at rest, possibly disrupting sleep and daily activities like dressing or carrying groceries. Inflammation can lead to swelling and stiffness, making joints feel weak or unstable. Some individuals may experience grinding or catching sensations when moving their arms, complicating simple tasks.
Diagnosis
A doctor can diagnose shoulder arthritis through a physical examination, assessing symptoms and pain levels. Patients may perform basic arm movements to evaluate muscle strength and joint stability. Blood tests and lab evaluations may help identify the specific type of arthritis.
X-rays will reveal the condition of the shoulder bones and highlight arthritis or bone spurs. In some cases, a CT scan or MRI may be ordered for a more detailed view of bone and soft tissue structures, both of which are painless imaging tests.
Treatment
Initial treatment for shoulder arthritis may involve non-surgical methods, including rest and pain relief. Over-the-counter or prescription medications can reduce inflammation and discomfort. If these measures are ineffective, corticosteroid injections may provide temporary relief.
Therapists can assist in strengthening the shoulder's surrounding muscles and recommend techniques to reduce stress on joints during daily activities.
Surgery
Shoulder arthroplasty is considered when non-surgical treatments yield minimal improvement. This procedure aims to alleviate pain and restore mobility. Typically performed as an inpatient surgery, patients may stay in the hospital for one to two days and receive general anesthesia or a regional nerve block.
Various shoulder replacement options exist:
- Total Shoulder Replacement: Suitable for patients with severe osteoarthritis and intact rotator cuff tendons. The surgeon replaces the damaged humeral head with a metal ball and the glenoid with a plastic socket.
- Hemiarthroplasty: Involves replacing only the humeral head, often used for shoulder fractures when the glenoid cartilage is healthy.
- Reverse Total Shoulder Replacement: Designed for those with torn rotator cuffs, severe arthritis, or failed previous surgeries. The ball and socket are reversed, allowing other muscles to lift the arm.
- Resurfacing Arthroplasty: Involves capping the humeral head with a metal prosthesis while preserving some cartilage.
Recovery
Recovery from shoulder surgery can take several months. Post-operative care includes limited arm movement and the use of a sling. A physical or occupational therapist will begin gentle movements on the first day after surgery.
Overall, rehabilitation typically spans three to six months, focusing on restoring strength and range of motion. Individual recovery times vary based on the surgery's extent and patient condition. Most individuals experience significant improvements in pain and functionality following shoulder replacement surgery, leading to an enhanced quality of life.
