Terrible Triad Injury of the Elbow Associated With an Olecranon Fracture: A Case Report With Three-Year Follow-Up

Terrible triad injuries of the elbow consist of elbow dislocation associated with fractures of the radial head and coronoid process and are characterized by significant instability. Variants that include an associated olecranon fracture are rare, and data regarding long-term functional outcomes and patient-reported outcome measures remain limited. We report the case of a 74-year-old female patient who sustained a terrible triad injury of the elbow associated with an ipsilateral olecranon fracture following a low-energy fall. This injury pattern has occasionally been referred to as a "terrible tetrad"; however, this term is not uniformly adopted in the literature. Unlike trans-olecranon fracture-dislocations, the present injury involved disruption of the ligamentous stabilizers, necessitating soft-tissue reconstruction in addition to osseous fixation. Surgical treatment was performed through a single posterior approach and included olecranon fixation, radial head arthroplasty, coronoid fixation, and repair with augmentation of the lateral collateral ligament complex. At three-year follow-up, the elbow was stable, with a flexion-extension arc from 25° to 115° and full forearm rotation. The Mayo Elbow Performance Score was 85, and the QuickDASH score was 4.5. Radiographs demonstrated fracture union, a well-positioned radial head prosthesis, heterotopic ossification, and early post-traumatic degenerative changes. This case highlights that comprehensive reconstruction addressing both osseous and ligamentous instability can result in acceptable mid-term functional outcomes in this uncommon injury pattern.