Terrible triad of the elbow and associated variants: a systematic review.

Background: The terrible triad of the elbow (TTE) is a complex injury consisting of simultaneous elbow dislocation or subluxation, radial head fracture, and coronoid fracture. During the initial assessment of a TTE, the typical severity of presenting pain, swelling, and limited range of motion may limit the ability to perform a thorough physical examination and thus divert a clinician's attention away from additional injuries to the ipsilateral upper extremity. Therefore, the purpose of this study was to review the literature for reported cases of concomitant ipsilateral upper extremity injuries associated with a TTE and discuss various strategies to increase clinician awareness to avoid underdiagnosis and missed diagnoses.

Methods: A systematic review of five databases in four languages (English, Spanish, French, and Portuguese), from inception to May 2021, was conducted. Articles describing a TTE with a concomitant osseous, chondral, ligamentous, or musculotendinous injury occurring on the ipsilateral upper extremity were included. The patients were divided into two groups, those presenting with a classic TTE and concomitant ipsilateral upper extremity injury (group 1) and those in whom a TTE variant was described (group 2). A TTE variant was defined as a combination of osseous and/or chondral injuries to the elbow other than the classic description of TTE, in which at least two of the three classical elements of a TTE (elbow dislocation, coronoid fracture, and radial head fracture) were present in addition to other unique elbow osteoarticular injury.

Results: Nineteen articles met inclusion criteria and were further analyzed. A total of 27 patients were analyzed, 23 from group 1 and 4 from group 2. Overall, 33 concomitant injuries were documented in group 1, the most common being an olecranon fracture (27.3%), followed by Essex-Lopresti injury, triceps tendon avulsion, and carpal fracture-dislocation with 4 (12.1%) cases each. Group 2 had four patients, all of whom presented with a unique variant of the classically described TTE.

Conclusion: Despite a characteristic radiographic appearance of the classic TTE, additional injuries of the ipsilateral extremity or variants of the classic TTE may be easily missed, especially in cases resulting from high-energy mechanisms of injury. By analyzing the available data on associated injuries and variants that may occur with a TTE, we hope to increase awareness so that clinicians may recognize these less common but more complex injury patterns.