Diagnosis

Patients who have lateral elbow instability present with a variable history and symptoms. Previous trauma can involve a documented dislocation of the elbow or an injury without dislocation. Patients report a sensation of their elbow intermittently "giving way" or "going out." Common mechanical symptoms include popping, catching, or snapping of the elbow. The symptoms typically manifest during loading of the joint in a slightly flexed position with the forearm in supination, such as when picking up a heavy briefcase. In patients whose elbows are more unstable, these episodes can occur with very minor loading, such as when turning over in bed during sleep.

Lateral Elbow Positioning

FIGURE 8.2. The deep (above) and superficial (below) layers supporting the lateral elbow. The deep layer consists of the lateral collateral and annular ligament complex with the tightly opposed overlying tendinous fibers of the supinator muscle. The superficial layer comprises the extensor tendons and their intermuscular fascia and septa. Note that the axis of the elbow is defined by the intermuscular septum between the extensor digitorum communis (EDC) and the extensor digiti quinti (EDQ). The extensor carpi ulnaris (ECU), with its broad fascial band, has the best mechanical advantage of the extensors in resisting posterolateral rotatory instability of the elbow. ECRL, extensor carpi radialis longus; ECRB, extensor carpi radialis brevis.

FIGURE 8.2. The deep (above) and superficial (below) layers supporting the lateral elbow. The deep layer consists of the lateral collateral and annular ligament complex with the tightly opposed overlying tendinous fibers of the supinator muscle. The superficial layer comprises the extensor tendons and their intermuscular fascia and septa. Note that the axis of the elbow is defined by the intermuscular septum between the extensor digitorum communis (EDC) and the extensor digiti quinti (EDQ). The extensor carpi ulnaris (ECU), with its broad fascial band, has the best mechanical advantage of the extensors in resisting posterolateral rotatory instability of the elbow. ECRL, extensor carpi radialis longus; ECRB, extensor carpi radialis brevis.

The physical examination is characteristically benign with respect to range of motion (although a slight loss of extension can be observed) and motor and sensory evaluations. Grip strength is typically normal as well. If the

FIGURE 8.3. Cadaveric specimen depicting the broad fas-cial band on the undersurface of the extensor carpi ulnaris (ECU) (arrow). This band originates on the inferior aspect of the humeral epicondyle and runs along the undersurface of the ECU at its inferior margin to insert onto the ulna. With the extensor muscles and intermuscular septa, it provides a secondary restraint to posterolateral elbow instability.

FIGURE 8.3. Cadaveric specimen depicting the broad fas-cial band on the undersurface of the extensor carpi ulnaris (ECU) (arrow). This band originates on the inferior aspect of the humeral epicondyle and runs along the undersurface of the ECU at its inferior margin to insert onto the ulna. With the extensor muscles and intermuscular septa, it provides a secondary restraint to posterolateral elbow instability.

patient's initial injury occurred long before this examination, he or she might only have minimal discomfort when the examiner palpates the bony or soft tissue structures of the lateral portion of the elbow. The elbow is clinically stable to varus and valgus stress. Plain radiographs (anteroposterior and lateral views) are usually negative, but the examiner might observe a small lateral avulsion fragment off the lateral epicondyle (Fig. 8.4).

Small Ossific Fragment Adjacent Elbow
A
Small Ossific Fragment Adjacent Elbow

FIGURE 8.4. (A) Anteroposterior and (B) lateral radiographs of a patient with posttraumatic rotatory instability of the elbow. Note the small avulsion fragments (arrows) seen adjacent to the radial head from proximal failure of the collateral and extensor tendon origins at the lateral epicondyle. The lateral radiograph reveals a concentrically reduced joint. Small lateral avulsion fractures are occasionally associated with this condition.

FIGURE 8.4. (A) Anteroposterior and (B) lateral radiographs of a patient with posttraumatic rotatory instability of the elbow. Note the small avulsion fragments (arrows) seen adjacent to the radial head from proximal failure of the collateral and extensor tendon origins at the lateral epicondyle. The lateral radiograph reveals a concentrically reduced joint. Small lateral avulsion fractures are occasionally associated with this condition.

Often, several physicians may have examined the patient, but may not have made a specific diagnosis.

Although clinically demonstrating frank posterolateral instability is difficult, the appropriate provocative maneuver often can reproduce subtle subluxation of the lateral portion of the elbow. One such maneuver is the posterolateral rotatory instability test.2 The examiner conducts this test with the patient's arm in adduction, forearm in supination, and elbow in approximately 40° to 45° of flexion. The examiner stabilizes the humerus with one hand, placing his or her fingers along the lateral ulno-humeral joint line. The examiner's contralateral arm applies a slight axial and valgus force while loading the patient's proximal forearm in supination. Gaping at the ulnohumeral articulation as the ulna and radial head sub-luxate from the humerus demonstrates instability (Fig. 8.5). This maneuver results in a posterolateral prominence as the radial head subluxates with the ulna away from the capitellum. The elbow subluxates during this maneuver but does not dislocate. Pronating and slightly flexing the joint reduce the ulnohumeral articulation. A palpable "clunk" occasionally accompanies reduction.

A positive posterolateral rotatory instability test is difficult to elicit in patients who are not anesthetized, especially in individuals who have well-developed musculature. Patients who have lateral rotatory instability characteristically resist this provocative maneuver. Guarding, in effect, constitutes a positive apprehension test. The clinician can conduct the examination most easily when the patient is anesthetized because the muscles are relaxed. Lateral stress radiographs aid in the diagnosis. A true lateral elbow film can be taken with the forearm maximally supinated or during the posterolateral rotatory instability test (Fig. 8.5B). This film might reveal a widened ulno-humeral articulation with an inferiorly subluxated radial head that is now posterior to the midline of the capitel-lum. Although not typically used to make the diagnosis, magnetic resonance imaging commonly reveals a disruption of the lateral collateral and tendinous origins at the humeral epicondyle. The clinician sometimes can observe subluxation of the lateral joint as well (Fig. 8.6).

Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

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