REIDER PART 1
07

Chapter 3 Elbow and Forearm 97

V

Figurę 3-56. The milking maneuver.

varus stress test are analogous to those of the valgus stress test, but the direction of force application is reversed. This time, the limb is positioned with the shoulder morę internally rotated. The examiner grasps the patient s limb above the elbow with one hand and below the elbow with the other hand and applies a controlled varus stress (Fig. 3-57). Again, care must be taken to avoid rotating the entire limb when the varus stress is applicd.

In the presence of abnormal laxity of the lateral liga-ment complex, the examiner feels the bones separate at the elbow when the varus stress is applied and come back together with a clunk when the stress is relaxed. As in the valgus test, comparison with the other side is helpful in determining whether a perceived increase in laxity is truły pathologic.

Posterolateral Rotatory Instability Test (Pivot Shift Test). The posterolateral rotatory instability test, or pivot shift test, is designed to detect posterolateral instability of the elbow, a condition that occurs owing to insufficiency of the portion of the lateral ligamcntous complex known as the lateral ulnar collateral ligament. This syndrome is manifested by episodes suggestive of subluxation or dislocation. The posterolateral rotatory instability test may be performed with the upper limb at the patient’s side or with the shoulder flexed so that the limb lies above the paticnt’s head. 0’Driscoll and col-leagues, who first described this test, preferred the latter position. The test is performed with the patient supine and the shoulder flexed overhead. The examiner grasps the patient’s forearm, externally rotating the shoulder to its limit to prevent humerał rotation and płacing the forearm in a supinated position. The test begins with the

Figurę 3-57. Varus stress test (arrow indicatcs direction of force applied to forearm).

patients elbow in fuli extension. The examiner applies valgus and axial compression forces to the elbow and a supination torąue to the forearm. This produces a rotatory subluxation of the ulnohumeral joint with a cou-plcd posterolateral dislocation of the radial head from the humerus (Fig. 3-58A). As the elbow is flexed to about 40°, the posterolateral rotatory subluxation increases to its maximum (Fig. 3-58B). The radial head creates a posterolateral prominence with an obvious dimple in the skin located just proximal to it. Additional flexion results in sudden reduction of the radiohumeral and ulnohumeral joints (Fig. 3-58C). The dimple disap-pears, and the radius and ul na can be felt and seen to snap back into place on the humerus. The palpable sub-luxation and reduction just described are usually appre-ciated only when the test is performed with the patient under generał anesthesia. If the test is performed with the patient awake, an abnormal result is signified by the patient s apprehension; only occasionally can a sudden reduction of the radiohumeral and ulnohumeral joints be elicited.

The physical fmdings in common conditions of the elbow and forearm are summarized in Table 3-1.