Os supratrochleare anterius: a very rare clinical case and review of literature.

Purpose: The accessory bones around the elbow are very rare variant structures, present in approximately 0.7% of cases. They can cause diagnostic problems and can be mistaken for pathological structures, especially when pain and limitation of elbow movements are present and a trauma can be traced in the patient's history. They are of different nature, either presenting within muscle tendons as sesamoids (brachialis and triceps brachii muscles) or presenting intra-articularly probably as separated or accessory ossification centres. The least common is the os supratrochleare anterius.

Methods: We present a case of a young male, featuring chronic blocking and 20° limited flexion of his right elbow, which bothered him during his occupation as a locksmith. In history, he suffered minor trauma to the elbow 20 years ago. X-ray and CT showed a large ossicle in the coronoid fossa of the humerus.

Results: The ossicle was surgically extracted in small pieces. The patient left satisfied with no mention of complaints.

Conclusion: The os supratrochleare anterius is a very rare accessory bone of the elbow, located in the coronoid fossa of the humerus which can mimic many pathological states, and limit movements and causing pain around the elbow.