Elbow dislocations associated with a medial epicondyle fracture and ulnar nerve palsy are uncommon injuries. We present the case of an 11-year-old girl with an elbow dislocation treated by closed manual reduction. The medial epicondyle fracture was missed initially until she developed an ulnar nerve palsy 2 months later. Intraoperatively we discovered the bony epicondyle piercing the joint capsule and compressing the ulnar nerve. Removal of the bony fragment relieved her symptoms and she returned to normal activities at 1 year follow-up. We would like to highlight this rare occurrence and present the detailed history and management of this case.