The results of treatment were reviewed for twenty patients who had sustained concomitant injuries of the lateral compartment of the radiohumeral joint and the ipsilateral distal radio-ulnar joint. The ages of the patients ranged from eight to seventy-four years (average, thirty-five years) and the duration of follow-up ranged from four months to twenty-seven years (average, 113 months). In fifteen patients, the injury of the wrist was diagnosed after a mean delay of seven years and eleven months (range, one month to twenty-six years). In all fifteen, the radial head injury was treated by excision, either initially or after some delay. After excision of the radial head, all fifteen patients complained of severe pain at the distal radio-ulnar joint. The results, on the basis of elbow and wrist scores of fair or better without complications, were satisfactory in only three patients. In the remaining five patients, in whom the injuries of both the elbow and the wrist had been identified at the initial evaluation, the radial head was either preserved or replaced. The results, on the basis of elbow and wrist scores of fair or better, were graded as satisfactory in four of these patients. Our data show that any injury to the lateral side of the elbow should prompt a careful evaluation of the ipsilateral distal radio-ulnar joint for associated instability.