ELBOW

Published on 16/03/2015 by admin

Filed under Orthopaedics

Last modified 16/03/2015

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CHAPTER 5

ELBOW

image

SELECTED MOVEMENTS

ACTIVE MOVEMENTS1 image

Supination

RESISTED ISOMETRIC MOVEMENTS3,4 image

TEST PROCEDURE

The muscles of the elbow are tested isometrically, with the examiner positioning the patient and saying, “Don’t let me move you.” From this position, the examiner tests elbow flexion, extension, supination, and pronation. Wrist extension and flexion also must be tested, because a large number of muscles act over the wrist as well as the elbow. The examiner should slowly and steadily build up resistance when testing isometric muscle strength.

CLINICAL NOTES

• If the patient has complained that combined movements under load, repetitive movements under load, or sustained positions under load cause pain, the examiner should carefully examine these resisted isometric movements and positions as well, but only after the basic movements have been tested isometrically.

• Muscle flexion power around the elbow is greatest in the range of 90° to 110° with the forearm supinated. At 45° and 135°, flexion power is only 75% of maximum.

• Research shows that men isometrically are two times stronger than women when testing elbow strength. In both men and women, extension is 60% of flexion and pronation is about 85% of supination.

• If the history indicates that concentric, eccentric, or econcentric movements have caused symptoms, these movements should also be tested with load or no load as required.

SPECIAL TESTS FOR LIGAMENTOUS INSTABILITY

Relevant Special Tests

Epidemiology and Demographics512

The elbow is the second most commonly dislocated joint in adults and the most commonly dislocated joint in children. Six in 100,000 people dislocate an elbow over a lifetime. Dislocations account for 10% to 25% of all injuries of the elbow.

The mean age for dislocation of the elbow is 30 years. About 40% of elbow dislocations occur during a sports activity, most often gymnastics, wrestling, basketball, or football. Dislocations occur 2 to 2.5 times more often in males than in females.

Medial collateral ligament injury is common with activities that require repetitive overuse. Young athletes who play overhead sports (e.g., baseball pitchers) often experience pain and injury to this ligament. The cause frequently is a combination of overuse and poor mechanics.

Relevant History

Patients may or may not have a prior history of damage to the elbow. Lateral instability occurs after elbow dislocation in 75% of cases.13 Athletes who participate in overhead sports may have a history of lower extremity or back pain that does not allow normal throwing mechanics. This can lead to excessive stress in the elbow, especially on the medial collateral ligament.

Relevant Signs and Symptoms

Dislocation/Subluxation

With dislocation, the elbow is very painful and increased swelling is noted at the joint. The elbow is held in 90º of flexion, and the patient appears to closely guard the upper extremity. The forearm appears shorter than the upper extremity or contralateral side. All movements of the elbow are painful and limited. Even with reduction, ROM is limited, the joints are swollen, and muscle spasm and (at end range) pain are present.

Mechanism of Injury

Dislocation/Subluxation

The definition of elbow dislocation implies a complete discontinuity of the ulnohumeral articulation with associated radiocapitellar disruption. This can occur with or without proximal radioulnar disruption, associated neurovascular injury, and/or residual elbow instability. Ligament damage can occur with or without a concomitant elbow dislocation, as in the case of elbow subluxation. A posterior elbow dislocation is caused by a fall on an outstretched arm with the elbow forced into hyperextension. Mechanically, the hand is supinated as the body rotates in a pronated direction in relation to the elbow; this produces a valgus force on the elbow. As the body continues in a forward motion, the elbow hyperextends and a posterior dislocation of the ulna in relation to the humerus occurs.

Repetitive Stress Injuries

The stability of the elbow relies on the stability and integrity of the ligaments. Ligaments are designed to resist primarily tensile loading. Activities that repetitively overstress the affected ligaments can lead to injury and eventual laxity. Damage to the medial collateral ligament occurs when a valgus force is applied to the elbow joint; damage to the lateral collateral ligament occurs when a varus force is applied. Such damage can be due to either trauma or repetitive overuse.