Monteggia fracture: an easy fracture to miss

To assess the incidence of missed Monteggia fracture by radiologists and bedside clinicians (emergency and orthopaedic doctors) at a tertiary hospital.

A comprehensive search was conducted on Picture Archiving and Communication System (PACS) and electronic medical records (EMR) between Jan 2010 and April 2019. All consecutive paediatric and adult patients who presented to the emergency department with the diagnosis of Monteggia fracture were included. The patient's emergency presentation medical notes and trauma film reports were compared. Most emergency presentations were discussed with orthopaedics; hence, this was combined as a single group (bedside clinician group). All images were blindly reviewed by a senior consultant radiologist. Results from the radiologist and bedside clinician groups were compared.

Fifty-one patients were identified; 4 were excluded as they were not true Monteggia fracture on review. Forty-seven patients were included in the study (age range 3-70 years, mean age 15 years). Thirty-three patients (70%) were correctly diagnosed by both groups. Twelve patients (25.5%) had a missed diagnosis by the radiologist's group. Seven patients (14.9%) were missed by the bedside clinicians. Five patients (10.6%) were missed by both groups with fractures detected on re-presentations. The most commonly missed finding was a radial head dislocation/subluxation, followed by a subtle ulnar fracture (confirmed by periosteal reaction development on subsequent radiographs) and an ulnar plastic deformity.

The Monteggia fracture is an important diagnosis, but it is not infrequently missed by radiologists and clinicians. Special attention to the radiocapitellar joint alignment and ulnar periosteum, and looking for a subtle ulnar fracture or plastic deformity would ensure correct diagnosis.