The shoulder is the most flexible joint in the body enabling a wide range of movements including, forward flexion, abduction, adduction, external rotation, internal rotation, and 360-degree circumduction.
Thus, the shoulder joint is considered the most insecure joint of the body but the support of ligaments, muscles and tendons function to provide the required stability.
Bones of the Shoulder
The shoulder is a ball and socket joint made up of three bones, namely the humerus, scapula and clavicle.
The end of the humerus or upper arm bone forms the ball of the shoulder joint. An irregular shallow cavity in the scapula called the glenoid cavity forms the socket for the head of the humerus to fit in. The two bones together form the glenohumeral joint, which is the main joint of the shoulder.
The term arthritis literally means inflammation of a joint but is generally used to describe any condition in which there is damage to the cartilage. Damage of the cartilage in the shoulder joint causes shoulder arthritis. Inflammation is the body's natural response to injury. The warning signs that inflammation presents are redness, swelling, heat, and pain.
A rotator cuff is a group of tendons in the shoulder joint that provides support and enables a wide range of motion. A major injury to these tendons may result in rotator cuff tears. It is one of the most common causes of shoulder pain in middle-aged and older individuals.
Impingement results in the young and middle-aged who engage in physical activities that require repeated overhead arm movements. The pain may be due to bursitis (inflammation of the bursa) overlying the rotator cuff or tendonitis of the cuff itself. In some circumstances, a partial tear of the rotator cuff may cause impingement pain.
Total shoulder replacement surgery is performed to relieve symptoms of severe shoulder pain and disability due to arthritis. In this surgery, the damaged articulating parts of the shoulder joint are removed and replaced with artificial prostheses. Replacement of both the humeral head and the socket is called a total shoulder replacement.
Reverse total shoulder replacement is an advanced surgical technique specifically designed for rotator cuff tear arthropathy. In this procedure, the humeral ball is placed in the glenoid cavity of the shoulder blade (scapula) and the plastic socket is placed on top of the arm bone.
Shoulder joint replacement can be performed by a traditional open approach or through a minimally invasive approach. The incision of a minimally invasive shoulder joint replacement is about 5 cm compared to 17 cm with the traditional approach. It involves less damage to the soft tissues and underlying muscles, enabling a faster recovery.