Instability of the Elbow Following

Background: Resection is a common procedure for the treatment of comminuted fractures of the radial head. While radial head resection is associated with a high success rate when performed for appropriate indications, a number of well-defined biomechanical complications have been reported following this procedure, including proximal migration of the radius, the development of valgus deformity, and recurrent elbow instability in the acute setting. However, pos-terolateral rotatory instability has not previously been recognized as a complication of radial head resection. While the absence of the radial head makes the diagnosis difficult, we have identified a series of patients with posterolat-eral rotatory instability following radial head resection. We believe that this instability is secondary to unrecognized lateral ulnar collateral ligament deficiency. Methods: Between November 1995 and September 2000, forty-two patients were evaluated because of elbow or forearm complaints following radial head resection. Seven patients (17%) were diagnosed with posterolateral rotatory instability on the basis of characteristic clinical and radiographic findings. Results: The study group included five men and two women with a mean age of forty-two years. All seven patients had had radial head excision for the treatment of a comminuted radial head fracture at a mean of forty-four months (range, four months to sixteen years) prior to referral. All seven patients had lateral elbow pain, a sense of instability and/or weakness, and a positive lateral pivot-shift test. Posterolateral rotatory instability secondary to lateral ulna