Simplifying Monteggia fracture-dislocation. All information have been collected from authentic sources.

1. Monteggia fracture-dislocation
Dr. Ashiqur Rahman
Resident Orthopedics
Dhaka Medical college Hospital

3. Introduction
 The injury described by Monteggia in the early 19th century (without
benefit of X-rays).
 A fracture shaft of the ulna associated with anterior dislocation of
the proximal radio-ulnar joint; the radio-capitellar joint is inevitably
dislocated or subluxated as well.
 More recently the definition has been extended to embrace almost
any fracture of the ulna associated with dislocation of the radio-
capitellar joint, including trans-olecrenon fractures in which the
proximal radio-ulnar joint remains intact.

4. Mechanism of injury
 Usually the cause is a fall on the hand; if at the moment of impactthe
body is twisting, its moment may forcibly pronate the forearm.
 The radial head usually dislocate forwards & the upper third of the
ulna fractures & bows forwards.
 Sometimes, the causal force is hyper-extension.

6. Monteggia classification based on:
- The direction of the radial head dislocation
- Apex of the associated ulnar fracture.
1. Type I:
- Most Common in children.
- Anterior dislocation the radial head
- Apex anterior of ulnar diaphyseal fracture at any level.

7.  Type II:
- Usually found in older patients.
- Posterior of posterolateral dislocation of the radial head.
- Apex posterior of ulnar diaphyseal or metaphyseal fracture.
 Type III:
- Lateral dislocation of the radial head
- A varus (apex lateral) fracture of the proximal ulna.

8.  Type IV:
- Anterior dislocation of the radial head
- Fracture of the both ulna and radius. ( At the same level
of the distal radius and ulna).

11. Clinical features
 The ulnar deformity may be obvious but the dislocated head of
radius is masked by swelling.
 A useful clue is pain & tenderness on the lateral side of the elbow.
 The wrist & hand should be examined for signs of injury to the radial
nerve.

12. X-rays
 With isolated # of the ulna, it is essential to obtain a true AP & true
lateral view.
 In # upper third of the ulna with forward bowing, the radial head
usually dislocated forward.
 Backward or lateral displacement of the ulna is likely to be associated
with posterior or lateral displacement of the radial head.
 Trans-olecrenon # are also associated with radial head dislocation

14. Treatment
 The key to successful treatment is to restore the length of the
fractured ulna; only then can the dislocated joint be fully reduced and
remain stable.
 In adult, this means an operation through a posterior approach.
 The ulna # must be accurately reduced, with the bone restored to full
length, and then fixed with a plate & screws.
 The radial head usually reduces once the ulna has been fixed.

15.  Stability must be tested through a full range of flexion and extension.
 If the radial head does not reduce, or is not stable, open reduction
should be performed.
 If the elbow is completely stable, then flexion-extension & rotation
can be started very soon after surgery.
 If there is doubt, the arm should be immobilized in plater with the
elbow flexed for 06 weeks.

18. Complications
1. Nerve injury: May be due to over-enthusiastic manipulation of
radial dislocation or during surgical exposure. The lesion
usually a neuropraxia, which will recover by itself.
2. Malunion: In adults, osteotomy of the ulna or perhaps excision of
the radial head may be needed.
3. Nonunion: Non-union of the ulna should be treated by plating &
bone grafting.
4. Myositis ossificans
5. Compartment syndrome

19. Special features in children
 The general features of Monteggia # are similar to those in adults.
 However, it is important to remember that the ulna # may be
incomplete (greenstick or plastic deformation).
 If this is not detected & corrected, the child may end up with chronic
subluxation of the radial head.
 Because of incomplete ossification of radial head & capitellar
epiphysis in children, these landmarks may not be easily defined on X-
ray & a proximal dislocation could be missed.

21.  The X-rays should be studied very carefully and, if there is any doubt,
X-rays should be taken of the other side for comparison.
 Incomplete ulnar fracture can often be reduced closed, although
considerable force is needed to straighten the ulna with plastic
deformation.
 The position of the radial head is then checked; if this is not perfect,
closed reduction can be completed by flexing & supinating the elbow
& pressing the radial head.

22.  The arm is then immobilized in a cast with the elbow in flexion &
supination, for 03 weeks.
 Complete fractures are best treated by open reduction & fixation.