Terrible triad injuries of the elbow: does the coronoid always need to be fixed?

BACKGROUND: The "terrible triad" of the elbow is a complex injury that can lead to pain, stiffness, and posttraumatic arthritis if not appropriately treated. The primary goal of surgery for these injuries is to restore stability of the joint sufficient to permit early motion. Although most reports recommend repair and/or replacement of all coronoid and radial head fractures when possible, a recent cadaveric study demonstrated that type II coronoid fractures are stable unless the radial head is removed and not replaced. QUESTIONS/PURPOSES: The purposes of this study were to determine the (1) range of motion; (2) clinical scores using the Disabilities of the Arm, Shoulder and Hand (DASH) and the Broberg-Morrey questionnaires; and (3) rate of arthritic changes, heterotopic ossification (HO), or elbow instability postoperatively in patients whose terrible triad injuries of the elbow included Reagan-Morrey type I or II coronoid fractures that were treated without fixation.
METHODS: Between April 2008 and December 2010, 14 consecutive patients were treated for acute terrible triad injuries that included two Regan-Morrey type I and 12 Regan-Morrey type II coronoid fractures. Based on the senior author's (DGS) clinical experience that coronoid fractures classified as such do not require fixation to restore intraoperative stability to the posterolaterally dislocated elbow, all injuries were treated by the senior author with a surgical protocol that included radial head repair or prosthetic replacement and repair of the lateral ulnar collateral ligament (LUCL) followed by intraoperative fluoroscopic examination through a range of 20° to 130° of elbow flexion to confirm concentric reduction of the ulnohumeral joint. Using this protocol, intraoperative stability was confirmed in all cases without any attempt at coronoid or anterior capsular repair. Repair of the medial collateral ligament or application of external fixation was not performed in any case. All patients were available for followup at a minimum of 24 months (mean, 41 months; range, 24-56 months). The mean patient age was 52 years (range, 32-58 years). At the followup all patients were evaluated clinically and radiographically by the senior author. Outcome measures included elbow range of motion, forearm rotation, elbow stability, and radiographic evidence of HO or arthritic changes using the Broberg and Morrey scale. Elbow instability was defined as clinical or radiographic evidence of recurrent ulnohumeral dislocation or subluxation at final followup. Clinical outcomes were assessed with the patient-reported DASH questionnaire and the physician-administered Broberg-Morrey elbow rating system.
RESULTS: The mean arc of ulnohumeral motion at final followup was 123° (range, 75°-140°) and mean forearm rotation was 145° (range, 70°-170°). The mean Broberg and Morrey score was 90 of 100 (range, 70-100, higher scores reflecting better results) and the average DASH score was 14 of 100 (range, 0-38, higher scores reflecting poorer results). Radiographs revealed mild arthritic changes in one patient. One patient developed radiographically apparent but asymptomatic HO. None of the patients demonstrated instability postoperatively.
CONCLUSIONS: These findings demonstrate that terrible triad injuries with type I and II coronoid process fractures can be effectively treated without fixation of coronoid fractures when repair or replacement of the radial head fracture and reconstruction of the LUCL complex sufficiently restores intraoperative stability of the elbow through a functional range of motion. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines to Authors for a complete description of levels of evidence.