Elbow and Forearm Overuse Injuries 

Overuse injuries of the elbow and forearm are very common in athletes.^{[1, 2]} Any sport that subjects an athlete to repetitive elbow flexion-extension or wrist motion can cause these syndromes. A simple way to approach these syndromes is to divide them into the different pathologies. Athletes can have tendinopathies of the triceps or biceps tendons.

Although lateral epicondylitis and medial epicondylitis are both overuse injuries, they are covered individually in other articles within this journal. Pronator syndrome is covered as a distinct entity of median nerve entrapment. Radial nerve injury is also in another article.^[3] This article includes injuries to the elbow capsule and olecranon area.

Overuse injuries to the forearm and elbow are very common in throwing and racquet sports.^{[4, 5, 6, 7, 8, 9, 10]} Any activity that entails repetitive flexion-extension of the elbow or pronation-supination of the wrist can lead to overuse injuries. As the number of recreational athletes increases, the incidence of these injuries increases.^[11] The physician must obtain a very comprehensive history when dealing with these injuries because a subtle finding often can determine the proper diagnosis.^{[7, 8, 10, 12, 13]} Obtaining a vocational history is also very important because many skilled laborers or assembly line workers perform the same offending motion at work.

For excellent patient education resources, visit eMedicine's Hand, Wrist, Elbow, and Shoulder Center and Sports Injury Center. Also, see eMedicine's patient education articles Repetitive Motion Injuries, Sprains and Strains, and Tennis Elbow.

Related eMedicine topics:

Biceps Tendinopathy

Little League Elbow Syndrome

Nerve Entrapment Syndromes

Related Medscape topics:

Resource Center Exercise and Sports Medicine

Resource Center Trauma

Frequency

United States

The frequency of elbow and forearm overuse injuries is difficult to determine because of the multiple comorbid states and diagnoses that are possible (see Differentials and Other Problems to Be Considered). Some of these are covered in this article.

The elbow is a complex joint that consists of 3 true joints that function as 1 joint.^{[1, 2]} The humeroulnar joint is a modified hinge joint and allows flexion and extension. The humeroradial joint functions not only as a hinge joint to allow flexion and extension, but also as a pivot joint that allows rotation of the radial head on the capitellum. The proximal radioulnar joint allows supination and pronation to occur. The combined motion of these joints allows a range of motion from 5-150º of flexion-extension and 75º of pronation to 80º of supination. Remember that the olecranon process of the ulna sits in the humeral olecranon fossa in 20º or less of flexion.

The ligamentous structures can be divided into the lateral and medial structures.^{[1, 2]} These ligaments are better described as thickenings of the capsule, rather than true ligaments. Of the 3 medial structures, the anterior medial collateral ligament (AMCL) is the most important, providing approximately 70% of the valgus stability of the elbow. On the lateral side, the lateral ulnar collateral ligament (LUCL) is the strongest of the 4 branches, providing varus support.

The annular ligament maintains the radial head position in the radial notch of the humerus. Dynamic stability is provided by 4 muscle groups that transverse the elbow. The biceps brachii, brachioradialis, and brachialis muscles are the major flexors of the elbow joint. The triceps and anconeus muscles achieve extension. The supinator and biceps brachii muscles provide supination. Pronation is achieved through the pronator quadratus, pronator teres, and flexor carpi radialis muscles.

Understanding where the 3 major nerves cross the elbow is also very important. Overuse injuries or direct trauma can affect these nerves. The median nerve crosses the joint medially between the 2 heads of the pronator muscle and consists of fibers from the C5-T1 spinal nerves. The ulnar nerve travels posterior to the medial epicondyle in the cubital tunnel, down the posterior medial side of the forearm and crosses the wrist in the Guyon canal. This nerve is composed of fibers from C8 and T1 spinal nerves. The radial nerve crosses the elbow laterally and branches into the superficial (sensory) and posterior interosseous nerve, which is purely motor in innervation. This branch goes deep through the arcade of Frohse, which is a common site of entrapment. The radial nerve is made up of branches from the C5-C7 spinal nerves.

Repetitive elbow flexion can cause biceps tendinosis or anterior capsule strain. Activity that involves forceful elbow extension can cause triceps tendinosis or posterior impingement syndrome. In addition, any activity that causes increased valgus stress on the elbow can also cause ulnar nerve injury, posterior impingement syndrome, or olecranon stress fractures. These injuries are common in throwing sports and overhead racquet sports. Sports that require a great deal of wrist flexion-extension or pronation-supination can lead to pronator syndrome or radial tunnel syndrome. Posterolateral rotatory instability is seen only after a posterior elbow dislocation.

Related eMedicine topics:

Biceps Tendinopathy

Elbow, Fractures and Dislocations - Adult

Little League Elbow Syndrome

Nerve Entrapment Syndromes

Ulnar Nerve Entrapment

Related Medscape topics:

Resource Center Exercise and Sports Medicine

Resource Center Trauma