Last Updated on August 29, 2021
Monteggia fracture-dislocations consist of a fracture of the proximal 1/3 of the ulnar shaft with concomitant dislocation/instability of the radial head. Often the ulnar fracture is obvious but radial head dislocation may be subtle and prone to be overlooked.
Therefore high injury of suspicion is required for correct diagnosis and it is important to view elbow and wrist joint in forearm bone fractures.
The injury is more common in children and comparatively rarer in adults.
Monteggia fracture is named after Giovanni Battista Monteggia, Italian surgeon who described it in the 19th century.
The peak incidence is seen between 4 and 10 years of age.
Monteggia fractures constitute about less than for fewer than 5% of forearm fractures.
Monteggia Vs Galeazzi Fracture
The Monteggia fracture is characterized as a forearm fracture in association with dislocation of the proximal radioulnar joint.
Galeazzi fracture is its counterpart where forearm fracture is associated with distal radioulnar joint. Galleazzi fractrure involves a fracture of radius and distal radioulnar joint.
Thus in Monteggia fracture, the fractured bone is ulna whereas in Galeazzi fracture, the fractured bone is the radius. In Monteggia fracture, there is an injury to proximal radioulnar joint and in Galeazzi fracture distal radioulnar joint.
Relevant Anatomy and Mechanism of Fracture
Ulna and radius bones constitute the skeletal framework of the forearm and participate in wrist and elbow joints.
In the context of forearm fractures, distal and proximal radioulnar joints are important.
The radial head articulates with humeral capitellum and with the radial notch of the proximal ulna to form the proximal radioulnar joint.
The radial head is stabilized by the annular and radial collateral ligaments. These ligaments have to be breached for a radial head dislocation to occur.
The distal radioulnar joint is formed by the articulation of the distal radius and ulna.
Out of the two bones radius rotates over ulna to perform supination and pronation of the forearm.
The radius and ulna bone are connected by an interosseous membrane which also acts as a stabilizer.
This is also responsible for the increased risk of radial injury when ulna fractures because any disruption of one bone affects other.
In Monteggia fracture, when ulna is fractured, the energy passes along the interosseous membrane which results, in the displacement of the proximal radius. Thus, there are the following injuries
- Disrupted interosseous membrane proximal to the fracture
- A dislocated proximal radioulnar joint
- A dislocated radiocapitellar joint.
Monteggia fracture may be part of the complex injury pattern as well. The associated, known, injuries are
- Olecranon fracture-dislocation
- Radial head fractures
- Coronoid fractures
- Lateral collateral ligament injury of elbow
- Terrible triad of elbow
The posterior interosseous nerve travels around the neck of the radius and then goes under supinator muscle.
Median and ulnar nerves enter the forearm distal to the elbow.
This proximity makes nerves vulnerable to injury when Monteggia fracture-dislocation occurs.
Monteggia fracture is a FOOSH injury
It can occur with both high energy and low energy injury. A high index of suspicion should be kept in case of patient having displaced ulna fractures without radial bone fracutre.
Classification of Monteggia Fracture
Classification of Monteggia fractures was given by Bado. Initially, Bado described four types of this lesion.
Type I Monteggia Fracture
Fracture of the ulnar diaphysis at any level with anterior angulation at the fracture site and an associated anterior dislocation of the radial head.
Type II Monteggia Fracture
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Fracture of the ulnar diaphysis with posterior angulation at the fracture site and a posterolateral dislocation of the radial head
Type III Monteggia Fracture
Fracture of the ulnar metaphysis with a lateral or anterolateral dislocation of the radial head.
Type IV Monteggia Fracture
Fracture of the proximal third of the radius and ulna at the same level with an anterior dislocation of the radial head.
After Bado, four different subgroups of the posterior Monteggia fracture [type II] were suggested by Jupiter et al. These subgroupings were based on the location of the ulnar fracture.
Type IIA
The ulnar fracture involves the distal olecranon and coronoid process.
Type IIB
The ulnar fracture is at the metaphyseal and diaphyseal juncture, distal to the coronoid.
Type IIC
The ulnar fracture is diaphyseal.
Type IID
The ulnar fracture extends along with the proximal third to half of the ulna.
Bado type I is the most common type of Monteggia fracture constituting almost two-third of the Monteggia fractures. Type III is next common, about 20%, followed by type II which is about 15%. Type IV is quite rare.
Types of Monteggia Fracture in Children
In children, the fracture pattern of the ulna is more important than the direction of the radial head.
These patterns are categorized as
- Plastic deformation
- Associated with 31% anterior dislocation of the head
- Incomplete (greenstick or buckle) fracture
- Complete transverse or short oblique fracture
- Comminuted or long oblique fracture
It is important to emphasize that all the patterns including plastic defmormity which is more likely to be missed need correction because the radial head reduction remains unstable until the deformity or fracture patterns is corrected. This also holds true for incomplete fractures of the ulna.
Clinical Presentation
There would be a history of fall on an outstretched hand or there could be a high energy trauma like motor vehicle injury.
The patient would present with pain in the forearm, swelling, and deformity.
On examination, there would be tenderness at the fracture site. The radial head is palpable in anterior, posterior, or anterolateral position depending on the dislocation.
The angulation of ulna generally points to the direction of radial head dislocation.
Generally speaking, the different fractures have the following type of radial head dislocation –
- Bado type I and IV lesions – Anterior/anterolateral
- Type II lesions – posterior
- Type III – laterally
Any other soft tissue including skin injuries and bony injury should be noted as it can affect the treatment decision.
The detailed neurovascular examination should be conducted.
Lab Studies
No investigations are required for diagnosis. However, for surgical correction, requisite investigations should be done.
Imaging
True anteroposterior and lateral x-rays of the forearm including both elbow and wrist joints should be done. If required special x-rays can be considered for proximal and distal radioulnar joint and elbow joint.
Ulnar fracture is usually obvious but radial head dislocation could be subtle and needs to be looked for intently.
Alignment of the radial head can be found by a simple test.
A line drawn down the shaft of the radius through the radial head should bisect the capitellum regardless of the position of the forearm.
If it does not, the radial head is subluxated or dislocated.
Treatment of Monteggia Fracture
Immediately pain is managed by splinting the limb and drugs for pain. Open wounds should be managed by cleaning and sterile dressing. The treatment approach is different in children and adults
In Children
Emergency closed reduction and plaster splint application under general anesthesia should be done in children. A posterior long arm splint with the elbow in 90° of flexion and full supination is applied.
Both fracture reduction and radius head relocation should be confirmed with the use of C-arm image intensifier. The position of the elbow when immobilized depends on the fracture pattern, as described earlier.
Children respond well to conservative treatment as the fractures are stable, heal faster and remodel well in case of mild residual angulation [less than 10 degrees]
Irreducible or unstable fractures and open fractures require surgical treatment.
In adults
Most of the fractures require open reduction and internal fixation.
The radial head should be reduced in the emergency and if the injury is closed, the surgical treatment could be delayed till the patient is stable and the radial head is reduced.
Open fractures and cases where the radial head is not reducible require immediate surgery as delay could lead to joint damage, nerve injury
Surgical Procedures
The surgical procedure is open reduction and fixation of ulna using plate screw construct. The radial head usually relocates with anatomical reduction of the ulna.
If the radial head does not reduce after ulnar reduction and fixation, open reduction of the radial head is done. Temporary fixation with k-wire may be done.
A long arm splint is provided after the surgery for 3 weeks.
Complications
- Bleeding
- Swelling
- Compartment syndrome
- Complications
- Nerve damage [mostly neuropraxia
- Mostly, function returns by 1-6 months
- Seen in 10% in acute injuries
- Malunion with radial head dislocation
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- Failure to obtain anatomic alignment of ulna
- Treated by ulnar osteotomy and open reduction of the radial head
- Radioulnar synostosis
- Elbow stiffness
- Myositis ossificans
- Infection
References
- Beutel BG. Monteggia fractures in pediatric and adult populations. Orthopedics. 2012 Feb. 35 (2):138-44.
- Delpont M, Louahem D, Cottalorda J. Monteggia injuries. Orthop Traumatol Surg Res. 2018 Feb. 104 (1S):S113-S120.
- Guitton TG, Ring D, Kloen P. Long-term evaluation of surgically treated anterior monteggia fractures in skeletally mature patients. J Hand Surg Am. 2009 Nov. 34 (9):1618-24.
