The results of operative resection of a post-traumatic proximal radioulnar synostosis performed by one surgeon in eighteen limbs of seventeen consecutive patients during an eight-year period were reviewed retrospectively. The resection was performed an average of nineteen months after the injury; eight limbs had the resection less than twelve months after the injury. A free fat graft was used in the first eight patients. No adjuvant non-steroidal anti-inflammatory medication or low-dose radiation was used postoperatively as prophylaxis against heterotopic ossification.We classified the proximal radioulnar synostoses into three subgroups: A indicated a synostosis at or distal to the bicipital tuberosity (four limbs), B indicated a synostosis involving the radial head and the proximal radioulnar joint (seven limbs), and C indicated a synostosis that was contiguous with bone extending across the elbow to the distal aspect of the humerus (seven limbs).The patients were followed for an average of thirty-four months (range, twenty-four to sixty months). The synostosis recurred in one patient, the only patient in the series who had sustained a closed head injury at the time of the initial injury. Additional complications included a fracture of the ulna, a broken pin on a hinged elbow distractor, and dislodgment of a free non-vascularized fat graft in one patient each. The seventeen limbs that did not have a recurrence regained an average of 139 degrees of rotation of the forearm. With the number of patients available, we could not detect a significant relationship between subsequent rotation of the forearm and the size of the synostosis, the use of interpositional fat, or the concomitant use of a hinged elbow distractor. The eight limbs that had resection of the synostosis less than twelve months after the injury regained an average of 144 degrees of rotation compared with 134 degrees in the nine limbs that had resection at least twelve months after the injury. This difference could not be shown to be significant.In this series, operative resection of a post-traumatic proximal radioulnar synostosis led to good results despite the lack of adjuvant radiation therapy or anti-inflammatory medication.