This study provides a minimum 2-year follow-up on 11 patients with posterior elbow dislocation associated with fractures of the radial head and coronoid, often referred to as the “terrible triad.” All patients sustained the injury secondary to a fall. Nine of 11 had a type III radial head fracture and all patients had a type II coronoid fracture. Seven of 11 elbows redislocated following closed manipulation alone. Five radial heads underwent open reduction internal fixation (ORIF) and 4 were resected. Three patients with fixation of the radial head also underwent lateral collateral ligament repair. None of the coronoid fractures were repaired. Three of 11 patients were considered failures secondary to either the development of a proximal radial ulnar synostosis or the development of severe destructive radiographic changes, one ultimately requiring a total elbow arthroplasty. Seven of 11 patients were rated as unsatisfactory. The 4 patients rated with a satisfactory result had undergone ORIF of the radial head and 2 of those patients had reattachment of the lateral collateral ligament complex. Nine of 10 patients had evidence of ulnohumeral arthrosis. The flexion-extension arc averaged 92 degrees (40 to 130 degrees) and forearm rotation averaged 126 degrees (40 to 170 degrees). The average score on the American Shoulder and Elbow Surgeons elbow evaluation instrument was 80 points (52-100). The average score according to the system of Broberg and Morrey was 76 points (34-98). This study confirms the difficulty associated with treatment of elbow fracture-dislocations involving the radial head and coronoid. With a significant concomitant fracture of the joint surface, operative intervention is required. Principles include restoration of the joint surface combined with soft-tissue repair of the collateral ligament and muscles origins at the humeral epicondyles. Without this, there is a high rate of recurrent instability, arthrosis, and overall an unsatisfactory outcome.
Although, the authors did not provide the outcome of patients treated with their current algorithm, general recommendations can be made based on the poor outcome of the treatment provided for these patients. In particular, elbow fracture-dislocations involving the coronoid and radial head should not be treated with radial head excision. Internal fixation or radial head replacement is recommended to restore the anterior buttress to the joint. In addition, due to the high recurrence of instability following this injury, the surgeon should be convinced of intra-operative stability. The soft-tissues should be carefully repaired and one should be prepared to provide supplemental fixation in the form of an external fixator. Most coronoid fractures associated with the terrible triad involve less than 50 percent of the coronoid height. Fixation, however, also helps to provide anterior stability to the joint and should be attempted whenever possible. Patients should be instructed concerning the severity of their injury and the overall potential for a poor outcome.
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Journal of Bone and Joint Surgery