Fractures of the forearm

Orthopedic Surgery

5th Stage

Fractures of the shafts of the radius and ulna

Mechanism of the injury:

Twisting force (fall on the hand) = spiral # at different level.

Angulating force = transverse # at sams level.
A direct blow = transverse # of one bone(ulna).
Additional rotation deformity may be produced by pull of the muscles attached to the radius;
they are biceps-supinator m.to the upper third.
Pronater teres to the middle third.
Pronator quadratus to the lower third.

Where (anatomical location) do most radial fractures occur?

 Proximal 6%
 Shaft 25%
 Distal metaphysis 70%
Why do fractures of the radius occur more common distally?
 Weaker bone (metaphyseal
 Less muscle coverage
 Longer lever arm


The classification based on these elements either:

1. Location of the fracture

2. Degree of completeness of the fractures
3. Direction of the resultant deformity

We can classify fractures according to the location of the fractures:

 proximal third.
 middle third
 distal third

Or we can classify shaft fractures based on the Degree of Completeness (Three stages):

 Plastic deformation
 Greenstick deformity
 Complete fracture

Or we can classify shaft fractures based on direction of the deformity

Supination + Apex volar

Pronation + Apex dorsal

Clinical Features:

 The # is obvious.
 The hand is examined for circulatory & neural deficit.
 repeated exam is necessary to detect an impending compartment syndrome.

Treatment

In children:
Closed treatment is usually successful in children because the tough periosteum tend to guide and then control the reduction.
The fragments are held in well-moulded full length cast from axilla to metacarpal shaft.
The position of reduction is checked by X-ray after a week and if it is satisfactory splintage is retained until both fractures are united(usually 6-8 weeks).
Occasionally operation is required either if fracture can not be reduced or if the fragments are unstable.

In evaluating the reduction. What are the acceptable limits of angulation, shortening and rotation?

Age
Angulaton
Angulaton
< 9 yrs.
15 degrees


≥ 9 yrs.
10 degrees
Rotation
Age
Mal-rotatation

< 9 yrs.

45 degrees

≥ 9 yrs.

30 degrees
Shortening
Usually not a problem

In adults:

If the fracture fragments are undisplaced and stable can be treated by closed treatment.
If the fracture fragments are displaced and unstable should be treated by open reduction and internal fixation.
Bone graft is advisable if there is comminution.

What are the indications for surgical intervention?

1. Open Fractures
2. Associated Soft Tissue Injuries
3. Inability to Maintain a Closed Reduction
4. Ipsilateral fractures
5. Re-fractures (relative)

Treatment of Open Fractures of radius and ulna:

Antibiotics and tetanus prophylaxis are given as soon as possible.
The wound are copiously washed and nerve function and circulation are checked.
At operation the wound are excised and extended and the bone ends are exposed and thoroughly cleaned.
If the wounds are absolutely clean the fractures are fixed with compression screw and plate and soft tissue can be closed.
If there is major soft tissue loss the bones are better stabilized by external fixation.

Complications

What are some of the more common complications that may be encountered?

1. Re-fracture

2. Malunion
3. Synostosis
4. Compartment Syndrome
5. Nerve Injury
6. Muscle Entrapment


Fracture of a single forearm bone;

They are important because;

an associated dislocation may be undiagnosed
nonunion is liable to occur unless it is realized that one bone takes just as long to consolidate as two.

Monteggia

(Ulnar Fracture- Radial Head Dislocation)

Mechanism of injury:

fall on the hand, at the moment of impact the body is twisting, its momentum may forcibly pronate the forearm. the radial head usually dislocates forewards & ulnar fracture bow foreward. sometimes the causal force is hyperextension.

Clinical features:

the ulnar deformity is usually obvious but the dislocated head of radius is masked by swelling.
A useful clue is pain and tenderness on the lateral side of the elbow.
The wrist and hand should be examined for signs of radial n. injury.

X-RAY

Of the forearm should include joint above &joint below. at least 2 views AP & lat.t. Monteggia Lesions.
Be wary of plastic deformation of ulna or minimally displaced ulna fracture with radial head dislocation.
On lateral radiograph the ulna should be straight.


The key to successful treatment is to restore the length of the fractured ulna only then can the dislocated joint be fully reduced & remain stable.

In adult

ORIF ulnar # accurately reduced, bone restore full length and then fix by plate & screws. the radial head usually reduced once the ulna has been fixed. if not open reduction should be performed.

In children

Closed reduction of ulnar angulation
Direct pressure over radial head
Usually will reduce with palpable clunk
Immobilize in reduced position
Supinate forearm for anterior dislocations
Frequent radiographic follow-up to document maintenance of reduction If unable to obtain or maintain reduction of radial head
Operative stabilization of ulnar fracture to correct angulation (oblique fractures may need plate fixation)
Assess radial head stability- flexion may help for anterior dislocation

Complications

NERVE INJURY; radial n. neuropraxi.
MALUNION unless the ulna perfectly reduced, the radial head remains dislocated.
NON-UNION;of the ulna should be treated by plating & bone.


Missed Monteggia Lesion
Anterior radial head dislocation
and heterotopic ossification

Healed prox ulna fx

with anterior bow

Galeazzi fracture-dislocation of the radius

Mechanism of injury:

Fall on the hand with a superimposed rotation force.the radius fractures in its lower third and the inferior radio-ulnar joint sublaxates or dislocates.

Clinical features:

Prominence or tenderness over lower end of the ulna.
Test for ulnar N.lesion.

X-RAY

A transverse or short oblique fracture is seen in the lower third of the radius with angulation or overlap.the distal radioulnar joint is subluxated or dislocared.
Treatment the important step is to restore the length of fractured bone.
 In children; close reductions often successful.
 In adult; reduction is best achieved by open operation and compression plating of the radius.
 The distal radioulnar joint is test for reduction and stability.
 If reduced but unstable;
 Post op. splintage 6weeks.
 If irreducible; Open reduction is needed to remove the interposed soft tissue