Coronoid fractures : how do we best classify them and what is the 'true terrible triad'?

The 'terrible triad' injury of the elbow is defined as a dislocation of the elbow with concomitant fractures of the radial head and coronoid process. The term was based on reports of poor outcomes following this pattern of injury. However, the 'terrible triad' concept has meant that some very complex elbow fracture-dislocations are considered alongside more benign injuries, leading to problems with our understanding and interpretation of the literature. This annotation explores how our knowledge of elbow stability has evolved, and how the importance of the coronoid to this is becoming increasingly clear. It suggests how we best define, classify, and manage fractures of the coronoid as part of these complex injuries.