Monteggia Fracture

By admin On Feb 11, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Monteggia Fracture

Monteggia Fracture

Paul D. Sponseller MD

Simon C. Mears MD, PhD

Basics

Description

Because the radius and ulna are bound by
ligaments and an interosseous membrane, a displaced fracture of the
ulna often is accompanied by dislocation of the radial head, a
combination termed a Monteggia fracture (Fig. 1).
The diagnosis sometimes is missed because the dislocation can be overlooked.
Reduction of both the fracture and the dislocation must be achieved.
Bado (1) classification:
- Most commonly used system
- Based on the direction of the dislocation
  of the radial head, which is the same as the direction of the apex of
  the ulnar fracture
- 4 types:
  - I: Anterior dislocation of the radial head (most common type)
  - II: Posterior dislocation of the radial head
  - III: Lateral dislocation of the radial head (2nd most common pattern in childhood)
  - IV: Anterior dislocation of the radial head in combination with a proximal radial fracture
    
    Fig.
    1. An angulated, isolated ulna fracture causes the radial head to
    dislocate. This combination is called a Monteggia fracture.

Epidemiology

Fracture occurrence is distributed evenly between males and females (2).

Incidence

Relatively uncommon
Peak incidence: Ages 4–10 years (3)
However, this fracture may occur at any age, including adulthood.

Prevalence

Most common in children: Bado type-I fractures, with plastic deformation of the ulna (4).
Most common in adults: Bado type I and type II fractures (5)

Risk Factors

Any child or adult with a fracture of the proximal or middle of the ulnar shaft should be considered at risk for this fracture.

Etiology

The ligamentous connections between the
radius and ulna cause the radial head dislocation to occur when the
ulna fractures, or vice versa.
Type I fracture mechanism: Hyperpronation or hyperextension
Type II fracture mechanism: Axial loading of a partially flexed elbow

Diagnosis

Signs and Symptoms

Signs:
- Swelling in the forearm and elbow
- In cases diagnosed late, a bump may be
  present over the elbow at the time a cast is removed for treatment of
  an ulnar fracture, indicating the dislocated radial head.
Symptoms:
- Acutely, tenderness over the elbow and deformity
- If diagnosed late, the unreduced radial
  head could block the full range of flexion or extension or cause
  clicking with pronation and supination.

Physical Exam

In acute cases, diagnosis should be made
primarily by radiography showing both the ulnar fracture and the radial
head dislocation.
In chronic cases, a prominence of the radial head is visible when the arm is out of the cast.
- This prominence represents the dislocated radial head and may be compared with the opposite side.

Tests

Imaging

Radiography:
- Plain radiographs are sufficient for diagnosis.
- All forearm fractures should include visualization of the elbow and wrist joints.
- These radiographs should be true AP and lateral views.
  - If they cannot be obtained on the same film, separate films of these regions should be ordered.
  - The physician should be available to help in positioning, if needed.
MRI is not required for diagnosis.

Pathological Findings

At the time of injury, the annular ligament of the radius is torn and becomes infolded.
If the radial head remains unreduced for several years, it degenerates because the cartilage wears away.

Differential Diagnosis

An isolated ulnar fracture may occur without radial head dislocation.
The status of the radial head may be determined by drawing a line on the radiograph through the radial shaft.
- This line should fall in the center of the capitellum of the distal humerus.
An isolated radial head dislocation may occur, but it is rare.
Congenital dislocation of the radial head does occur.
- May be distinguished by changes in the
  shape of the radial head: Overgrowth and loss of the normal concave
  reciprocal articular surface

P.263

Treatment

General Measures

For children, closed reduction usually is successful for treating both the dislocated radial head and the ulnar fracture.
The mechanism used to reduce the ulnar fracture also is used to maintain reduction of the radial head fracture.
- Type I fractures: The forearm should be in supination to midposition, and the elbow should be in flexion of >110°.
- Type II fractures: The elbow should be in extension.
In both type I and type II fractures, the radial head may require a push to place it properly.
An above-the-elbow cast should be applied, and a bivalved cast should be used if substantial swelling is present.
A radiograph should be obtained after reduction to confirm that alignment is satisfactory.
Unstable or displaced fractures after reduction:
- In children: Require open reduction and fixation
- In adults: Require open reduction and internal fixation
Follow-up in 1 week
Late detection of a Monteggia fracture:
- 1–3 weeks after injury, the radial head may require open reduction, even in children.
- >3 weeks after injury, reconstruction of the annular ligament of the radial head may be necessary.

Special Therapy

Physical Therapy

Adults often need therapy to regain optimal motion.
In children, physical therapy is not needed because parents can do the necessary exercises with them.

Surgery

If the ulnar fracture cannot be
maintained or reduced, open reduction and internal fixation should be
performed, which usually causes the radial head to become and remain
reduced.
If it is not reduced, then an open reduction of the radial head should be performed.
In a child, internal fixation of the ulna may be done with an intramedullary nail if closed reduction has failed.
In adults, a Monteggia fracture should be
treated directly with open reduction and internal fixation (rigid plate
and screws) of the ulna.
- Radial head reduction only if needed
Late reconstruction of the annular ligament of the ulna is done using the Bell-Tawse technique (6).
- A strip of triceps fascia is used to reconstruct the ligament and is anchored to the ulna.

Follow-up

In children, immobilization is continued for 6 weeks.
In adults, because of a greater risk of stiffness, carefully supervised ROM may be started earlier.

Disposition

Issues for Referral

Monteggia fractures should be referred to an orthopaedic surgeon promptly to ensure timely and adequate reduction.

Prognosis

With careful reduction and follow-up, the prognosis is good (3).
Stable injuries in children have an excellent prognosis with closed treatment.
Bado type I injuries are thought to have a worse prognosis (7).
Injuries that are associated with coronoid or radial head fracture also have poorer outcomes (2).
Patients with missed injuries have a poorer prognosis.
Results of late reconstruction are unpredictable (8).

Complications

Redislocation
Stiffness
Proximal radioulnar synostosis
Elbow instability
Nerve injury (usually radial) at time of radial head dislocation (9)

Patient Monitoring

The patient should be seen 1 week after injury to rule out redisplacement.
Additional follow-up should be continued until ROM is satisfactory.

References

1. Bado JL. The Monteggia lesion. Clin Orthop Relat Res 1967;50:71–86.

2. Ring D, Jupiter JB, Simpson NS. Monteggia fractures in adults. J Bone Joint Surg 1998;80A: 1733–1744.

3. Wiley JJ, Galey JP. Monteggia injuries in children. J Bone Joint Surg 1985;67B:728–731.

4. Ring D, Jupiter JB, Waters PM. Monteggia fractures in children and adults. J Am Acad Orthop Surg 1998;6:215–224.

5. Llusa Perez M, Lamas C, Martinez I, et al. Monteggia fractures in adults. Review of 54 cases. Chir Main 2002;21:293–297.

6. Bell Tawse AJS. The treatment of malunited anterior Monteggia fractures in children. J Bone Joint Surg 1965;47B:718–723.

7. Givon U, Pritsch M, Levy O, et al. Monteggia and equivalent lesions. A study of 41 cases. Clin Orthop Relat Res 1997;337:208–215.

8. David-West KS, Wilson NIL, Sherlock DA, et al. Missed Monteggia injuries. Injury 2005;36: 1206–1209.

9. Ristic S, Strauch RJ, Rosenwasser MP. The assessment and treatment of nerve dysfunction after trauma around the elbow. Clin Orthop Relat Res 2000;370:138–153.

Miscellaneous

Codes

ICD9-CM

813.03 Closed Monteggia fracture
813.13 Open Monteggia fracture

Patient Teaching

At the time of initial consultation, patients should be counseled about the risk of redislocation.
Such counseling helps encourage compliance with follow-up care and exercises.

FAQ

Q: What is the prognosis of a Monteggia fracture in a child?

A:
The prognosis of stable fractures treated without surgery is excellent.
Missed fractures that are displaced have a much poorer outcome.