Osteology of the coronoid process with clinical correlation to coronoid fractures in terrible triad injuries

BackgroundTerrible triad complex elbow fracture-dislocations are represented by elbow dislocations associated with fractures of the coronoid and radial head. Published literature has focused on classifying coronoid fractures by their radiographic morphology on plain x-ray images and computed tomography imaging. No study has specifically related native coronoid osteology to in situ fracture morphology. We identified 3 distinct bony regions of the coronoid, (medial, intermediate, and lateral ridges) with correlation to common fracture patterns associated with terrible triad injuries.MethodsCoronoid osteology in 8 fresh frozen cadaveric elbows was examined, and three distinct ridges were identified and dimensions measured.ResultsThe measurements were compared with retrospective intraoperative measurements taken of coronoid fracture fragments being stabilized during terrible triad injury repair.ConclusionClassification of native coronoid process anatomy into functional ridges (medial, intermediate, lateral) may improve our understanding of coronoid fracture patterns in unstable terrible triad injuries.