Idiopathic anterior dislocation of the radial head: symptoms, radiographic findings, and management of 8 patients.

Background: Radial head dislocation may occur during trauma or in association with congenital diseases, or it may be developmental or idiopathic. Reports of idiopathic dislocation of the radial head have been scarce. The symptoms, radiographic findings, and management of idiopathic dislocation of the radial head have not been well described in the literature.

Methods: During the past 28 years, we have encountered 8 cases of idiopathic anterior dislocation of the radial head (mean patient age, 12.5 years). In only 1 case did the patient and/or the patient's parents recall any preceding trauma or injury to the affected limb. Patients' complaints included a bulging mass, pain, and limited elbow flexion. Radiographically, the shape of the radial head was flat or slightly convex. Seven of the patients were treated with open reduction of the radial head and angulation osteotomy of the ulna. The other patient's radial head was stabilized without osteotomy.

Results: The mean postoperative follow-up period was 4.5 years. In patients whose elbow flexion was limited before surgery, improvement to more than 125° occurred. The bulging mass in the cubital fossa disappeared. None of the patients complained of disability during activities of daily living or sports participation. Radiographically, the radial head remained in the reduced position in all patients in whom open reduction of the radial head with angulation osteotomy of the ulna was performed.

Conclusions: We have described the symptoms, radiographic characteristics, and treatment of idiopathic anterior dislocation of the radial head. Open reduction of the radial head combined with angulation osteotomy of the ulna yielded favorable results both clinically and radiographically.