Impact of Ulnar Fracture Level on Radial Head Dislocation - A Monteggia Fracture Study

Q: What is the main clinical problem addressed by this study?

Radial head dislocation in Monteggia injuries can be misdiagnosed or overlooked on standard elbow radiographs, which may lead to further complications.

Q: How did the study compare Monteggia fracture with isolated proximal ulnar fracture?

It analyzed differences in ulnar fracture pattern characteristics, especially the distance from the coronoid tip to the fracture site and related fracture angulation.

Q: What threshold distance from the coronoid tip was associated with higher risk of Monteggia fracture?

A coronoid tip to fracture distance within 7.3 cm was more likely to result in Monteggia fracture than an isolated proximal ulnar fracture.

Sep 29, 2026

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Monteggia fracture combines a proximal ulnar fracture with radial head dislocation, yet radial head dislocation can be missed on elbow radiographs, increasing risk of complications. This single-center retrospective study compared ulnar fracture pattern features between Monteggia fracture and isolated proximal ulnar fracture, focusing on how close the fracture was to the coronoid and which pattern more often led to radial head dislocation.

LanguageEnglish

CategoryHealthcare

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Pages6

Reading Time15 min

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Abstract

Background

Methods

Results

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Introduction

J Chin MedAssoc Original article Impact of ulnar fracture level on radial head dislocation: A Monteggia fracture study Kuan-Yu Huanga, Chun-Yu Chena,b,*, Kai-Cheng Lina aDepartment of Orthopaedics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC; bDepartment of Occupational Therapy, Shu-Zen Junior College of Medicine and Management, Kaohsiung, Taiwan, ROC Abstract Background: Monteggia fracture is defined as a combination of a proximal ulnar fracture with radial head dislocation. Radial head dislocation may be misdiagnosed under an elbow radiograph, leading to further complications. This study aimed to compare the ulnar fracture pattern characteristics between Monteggia fracture and an isolated proximal ulnar fracture in terms of how close the fracture site is to the coronoid and what type of fracture pattern is more likely to result in radial head dislocation. Methods: This single-center retrospective study, conducted from January 2014 to June 2022, included adult patients with proximal to midshaft ulnar fractures, excluding nonacute trauma, revision surgeries, and intra-articular fractures. All patients underwent anteroposterior (AP) and lateral elbow radiographs and forearm radiograph. Fracture patterns and injury mechanisms were recorded for analysis. Results: We included 51 patients in this study. The mean age was 38.5 ± 16.1 years, and 70. 1% were men (n = 36) . Monteggia fractures were classified according to the Bado classification into type I (n = 5), type II (n = 7), type III (n = 8), and type IV (n = 0) . Traffic accidents comprised 63% of the injuries (n = 32), and 45% were oblique type ulnar fractures (n = 23) . Monteggia fracture and proximal ulnar fracture presented with mean distance from coronoid tip to fracture of 6.12 ± 2.32 cm and 9.00 ± 3.00 cm (p < 0.01) . As per the receiver operating characteristic curve (ROC), the distance from coronoid tip to fracture of 7.33 cm had the highest area under the curve (AUC) value (0 .807) . Angulations of Monteggia fracture and isolated ulnar fracture were 24.02° ± 12. 10° and 10.77° ± 8. 10° (p < 0 .01) . However, there were no differences in the length of the fracture line between two groups. Conclusion: The distance from coronoid tip to fracture within 7.3 cm is more likely to cause a Monteggia fracture than an isolated proximal ulnar fracture. Otherwise, a Monteggia fracture is prone to more severe angulation. Keywords: Forearm fractures; Monteggia fracture; Proximal ulnar fracture; PRUJ injury; Radial head dislocation 686 [www.ejcma.org](www.ejcma.org) Original Article. (2025) 88:9 J Chin MedAssoc Lay Summary: When someone breaks the forearm bone near the elbow (called the ulna), they might also dislocate the joint atthe top of the other forearm bone (the radius) . This injury can be missed on standard radiographs, leading to pain, stiffness, and long-term problems. This study found that when the break occurs within 7.3 cm of the elbow joint, the risk of joint dislocation is much higher. These findings can help doctors better detect hidden injuries and plan more accurate treatments, improving patient recovery. 1. INTRODUCTION Giovanni Battista Monteggia first described the Monteggia fracture in 1814, defining it as a combination of proximal ulnar fracture and radial head dislocation. Midshaft forearm fractures occur less frequently (average: 1%-2%) than distal forearm fractures.1 Hence, a concomitant radial head dislocation may be misdiagnosed if only the affected part (forearm) is radiographed and the proximal joint (elbow) is not. An undiagnosed and unattended radial head dislocation may cause serious complications, including decreased range of motion and early osteoarthritic alterations in the elbow joint.2–4 Thus, clinicians should cautiously identify any radial head dislocation on radiographs when dealing with patients with proximal ulnar fractures. Furthermore, the relocation of a correctly diagnosed radial head disloc

FAQs

What is the main clinical problem addressed by this study?

Radial head dislocation in Monteggia injuries can be misdiagnosed or overlooked on standard elbow radiographs, which may lead to further complications.

How did the study compare Monteggia fracture with isolated proximal ulnar fracture?

It analyzed differences in ulnar fracture pattern characteristics, especially the distance from the coronoid tip to the fracture site and related fracture angulation.

What threshold distance from the coronoid tip was associated with higher risk of Monteggia fracture?

A coronoid tip to fracture distance within 7.3 cm was more likely to result in Monteggia fracture than an isolated proximal ulnar fracture.

Sep 29, 2026

Uploaded by Finn