Elbow Injuries and Disorders

Anatomy

In order to understand disorders of the elbow, an appreciation for the basic anatomy is required. The elbow joint consists of the articulation of the upper arm, or humerus, with the two bones of the forearm, the radius and ulna. The radius and ulna articulate with the lateral and medial portions of the humerus (termed condyles) in a manner allowing for hinge-like movement, as well as pivoting movements termed pronation and supination. The elbow joint movements are stabilized posteriorly by the olecranon process of the ulna bone, and laterally and medially by two major ligament complexes. Bursa, or fluid filled sacs, facilitate movement by reducing friction between elbow components.

Overuse

Humeral epicondylitis is the most common elbow problem and is a result of overuse of the elbow joint. The associated pain is a result of inflammation of the area where the forearm muscles attach to the humerus. The inflammation is more commonly on the lateral humerus (aka “tennis elbow”), but can also occur on the medial side (aka “golfer's elbow”) or posteriorly around the triceps tendon. These conditions are most common between the age of 30 and 50 in those who perform repetitive hand or arm movements as a part of their profession.

Repetitive forceful extensions of the elbow can also cause bony collisions between the olecranon and the humerus, leading to a condition called posterior impingement syndrome. The bones will often thicken and or fragment in response to the trauma, leading to pain over the olecranon process, limited range of motion, and swelling.

Overuse of the elbow can also lead to inflammation of the bursa or muscle tendons, conditions termed bursitis and tendonitis, respectively. Bursitis most commonly involves the olecranon bursa, and tendonitis most commonly involves the biceps or triceps tendons.

Trauma

Trauma to the elbow joint can typically result in two types of injury: fracture or dislocation. Elbow dislocation often results from falling on an outstretched arm. Dislocation in any direction is possible, but posterior movement of the forearm bones is most common. A dislocated elbow will commonly be held at a 45-de-gree angle and will often have a clear deformity on or around the olecranon process. In children, a partial dislocation called radial head subluxation is possible. This occurs when a child's arm is forcibly pulled while in the extended position, causing the radial head to slip underneath the annular ligament (part of the lateral ligament complex that stabilizes the radial head articulation with the ulna).

Elbow fractures most commonly involve the radial head or olecranon process. Radial head fractures account [Page 591]for a third of elbow fractures, and often result from falling on a partially flexed but outstretched arm. Symptoms include point tenderness on the radial head, pain with pronation and supination, decreased range of motion, and possibly swelling. Olecranon process fractures generally result from direct trauma to the posterior elbow, often from falling backward. Alternatively, and less commonly, the olecranon suffers a stress fracture from forceful triceps muscle contraction while the arm is flexed, as in throwing a baseball. Much less commonly, the humerus may be fractured. Fractures above the condyles are termed supracondylar fractures, and are most common in kids under the age of 10. Although rare, condylar fractures can also occur.

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