The shoulder joint is a ball and socket joint. A 'ball' at the top of the upper arm bone (the humerus) fits neatly into a 'socket', called the glenoid, which is part of the shoulder blade (scapula). The labrum is a ring of fibrous cartilage surrounding the glenoid for stabilization of the shoulder joint. The biceps tendon attaches inside the shoulder joint at the superior labrum of the shoulder joint. The biceps tendon is a long cord-like structure which attaches the biceps muscle to the shoulder and helps to stabilize the joint.
The shoulder joint is the most flexible joint of the body. It allows various motions of the hands making it possible for us to do a vast array of different activities. However, its flexibility makes it more prone to injuries. A fracture is a break in the bone that commonly occurs because of injury, such as a fall or a direct blow to the shoulder. A fracture of the upper part of the arm (proximal humerus) is more common in elderly individuals and its frequency increases with age.
Proximal Humerus Fractures
The humerus is the upper arm bone and it forms two joints —shoulder joint and elbow joint. The proximal humerus refers to the upper end of the arm bone, which forms the shoulder joint. Fractures of the proximal humerus are common in elderly individuals, suffering from osteoporosis. Fractures may be caused by traumatic injuries such as a fall on outstretched hand, from greater heights or motor vehicle accidents. In younger individuals, severe trauma can cause these fractures.
Proximal humerus fractures can be categorized into 4 groups:
- Greater tuberosity fractures: Greater tuberosity is the insertion site for attachment of rotator cuff tendons. Greater tuberosity fractures are less common and are seen in cases of shoulder dislocations and in those with osteoporosis.
- Lesser tuberosity fractures: These fractures are often caused by posterior shoulder dislocations or traumatic muscle contractions by electrical shock or convulsions. If left untreated, these fractures cause subscapularis muscle (stabilizer and mobilizer muscle) deficiency and require a major muscle transfer procedure.
- Surgical neck fractures: Fractures of the surgical neck are most common in patients with osteoporotic bone. These fractures also damage the axillary nerve that carries sensory impulses to the shoulder.
- Humeral head fractures: Humeral head fractures occur often in elderly individuals and chances are increased in those with osteoporotic bone. These fractures occur in younger individuals by significant trauma whereas a mild traumatic injury can cause this type of fracture in elderly individuals with osteoporosis.
In addition to above, another type of proximal humerus fractures is two, three, and four part fractures, a fracture that causes multiple fragmentation of the proximal humerus.
Patients with proximal humerus fractures experience severe pain, swelling, and restricted motion of the shoulder.
Proximal humerus fractures are diagnosed by physical examination, X-ray of the affected area and/or computerized tomography (CT) scan.
Most proximal humerus fractures are minimally displaced and can be treated with conservative approaches such as use of sling to immobilize and early physical therapy to improve the functional outcome. Surgery may be necessary in displaced fractures. The multiple fragments are fixed with plates, screws, or pins and in severe cases a shoulder replacement surgery is performed.