The shoulder is a ball and socket joint made up of three bones, namely the humerus, scapula, and clavicle. The ends of all articulating bones are covered by smooth tissue called articular cartilage which allows the bones to slide over each other without friction enabling smooth movement.
The ligaments of the shoulder joint include coraco-clavicular ligaments, acromio-clavicular ligament, coraco-acromial ligament, and glenohumeral ligaments.
The rotator cuff is the main group of muscles in the shoulder joint and is comprised of 4 muscles. The deltoid muscle forms the outer layer of the rotator cuff and is the largest and strongest muscle of the shoulder joint.
Two important groups of tendons in the shoulder joint are the biceps tendons and rotator cuff tendons.
The nerves of the arm pass through the shoulder joint from the neck. These nerves form a bundle at the region of the shoulder called the brachial plexus. The main nerves of the brachial plexus are the musculocutaneous, axillary, radial, ulnar and median nerves.
Blood vessels travel along with the nerves to supply blood to the arms. Oxygenated blood is supplied to the shoulder region by the subclavian artery that runs below the collarbone. As it enters the region of the armpit, it is called the axillary artery and further down the arm, it is called the brachial artery. The main veins carrying de-oxygenated blood back to the heart for purification include axillary vein, cephalic vein, and basilica vein.
The shoulder is the most flexible joint in the body enabling a wide range of movements including forward flexion, abduction, adduction, external and internal rotation, and 360-degree circumduction.
Treatment of shoulder injuries includes non-surgical and surgical measures.
Shoulder Joint Replacement
Shoulder joint replacement is a surgical procedure performed to replace a damaged shoulder joint with artificial implants. It is usually performed to relieve shoulder pain when the joint is severely damaged by osteoarthritis, rheumatoid arthritis, post-traumatic arthritis, rotator cuff tear arthropathy, avascular necrosis (tissue death), fracture and failed former shoulder replacement surgery.
During the surgery an incision is made over the affected shoulder to expose the shoulder joint. The humerus is separated from the glenoid socket of the scapula. The arthritic parts of the humeral head and socket are removed and prepared. A carefully designed glenoid component made of plastic is attached to the socket with bone cement, and the humeral component, consisting of a metal ball attached to a stem, is cemented with bone graft or press-fitted into the upper arm bone. The two ends are brought together, and the joint capsule is stitched closed to hold the joint in place. The muscle and tendons are then repaired and skin is closed. This procedure is called a total shoulder replacement. Depending on the level of damage to the joint, your doctor may choose to replace only a part of the joint:
- Damaged humeral head is replaced with a prosthetic ball and stem (stemmed hemiarthroplasty)
- Damaged humeral head is replaced with only a cap-like prosthetic head, without stem (resurfacing hemiarthroplasty)
As with all surgical procedures, shoulder joint replacement surgery may be associated with certain complications such as infection, dislocation or instability of the implanted joint, fracture of the humerus, damage to nerves or blood vessels, blood clots (deep vein thrombosis), problems with wound healing, wearing of the joints or scar formation.
Arthroscopy is a minimally invasive diagnostic and surgical procedure performed for joint problems. Shoulder arthroscopy is performed using a pencil-sized instrument called an Arthroscope. The arthroscope consists of a light system and camera to project images to a computer screen for your surgeon to view the surgical site. Arthroscopy is used to treat disease conditions and injuries involving the bones, cartilage, tendons, ligaments, and muscles of the shoulder joint.
The shoulder joint is made up of a ball and socket joint, where the head of the humerus (upper arm bone) articulates with the socket of the scapula (shoulder blade) called the glenoid. The two articulating surfaces of the bones are covered with cartilage, which prevents friction between the moving bones enabling smooth movement. Tendons and ligaments around the shoulder joint provide strength and stability to the joint. Injury and disease to the bones or soft tissues of the shoulder joint can make it instable, and lead to pain, inflammation and reduced mobility.
Shoulder arthroscopy is indicated to treat the following shoulder conditions when conservative treatment such as medication and therapy fails to relieve pain and disability:
- Shoulder Impingement: this occurs when the shoulder blade applies pressure on the underlying soft tissues when the arm is lifted
- Rotator cuff tear
- Frozen shoulder or stiffness of the shoulder joint
- Shoulder Instability this occurs when the head of the upper arm bone slips out of the socket of the shoulder blade’s glenoid cavity either due to injury or overuse
- Biceps rupture occurs when the tendons attaching the bicep muscle to the shoulder or elbow tears
- Damaged cartilage or ligaments
- Bone spurs or bony projections
- Arthritis of the collarbone
Your surgeon performs shoulder arthroscopy under general or regional anesthesia. You may be positioned lying down on your side with your arm propped up or sitting in a semi-seated position. Sterile fluid is injected into the shoulder joint to expand the surgical area so your surgeon has a clear view of the damage and room to work. A button-sized hole is made in the shoulder and the arthroscope is inserted. Your surgeon can view images captured by the camera in the arthroscope on a large monitor. Surgical instruments are introduced into the joint through separate small holes to remove and repair the damage to the joint. After surgery, the instruments are removed and the incisions are closed with stitches or small sterile bandage strips.
After the surgery, the small surgical wounds take a few days to heal and the surgical dressing is replaced by simple Band-Aids. The recovery time depends on the type and extent of problem for which the procedure was performed. Pain medications are prescribed to keep you comfortable. The arm of the affected shoulder is placed in a sling for a short period as recommended by your doctor. Physical therapy is advised to improve shoulder mobility and strength after the surgery.
The advantages of arthroscopy compared to open surgery with a large incision include
- Less pain
- Fewer complications
- Shorter hospital stay
- Faster recovery
Risks and complications
Complications of shoulder arthroscopy include infection, bleeding, damage to nearby nerves or blood vessels, or delayed healing after the surgery. In certain cases, stiffness of the shoulder joint may occur after the surgery. It is important to participate actively in your physical therapy to prevent this from occurring.