Common fractures of the forearm

Monteggia Fracture-dislocation

Defined as fracture shaft of ulnar, together with disruption of the proximal radioulnar joint and dislocation of radiocapitallar joint..
nowadays the term includes fracture of olecranon with radial head dislocation.

The mechanism of injury is usually fall on an out-stretched hand with hyper-pronation of the forearm.

Clinical features

The deformity over the site of fracture is usually obvious.
However, the dislocated radial head can be obscured by the presence of swelling.

Pain and tenderness over the lateral aspect of elbow joint is suggestive.

It can be complicated as a radial nerve injury, causing wrist drop or injury to it's branch, the posterior interosseous nerve, causing finger drop.

Radiological features

An AP view of the elbow joint usually shows clearly the fractured shaft of ulna, and the head of radius no longer pointing towards the capitulum..if it dislocated, it lies in a plane anterior to capitulum..



Complications

1) Nerve injury
Usually caused by over-enthusiastic surgical manipulation of the dislocated radial head
However, it's a neuropraxic injury, where recovery is expected within months

2) Mal-union
Caused by imperfect reduction of the fracture, where the radial head remains dislocated.
Restricted flexion of elbow joint.
Requires open reduction and internal fixation, with excision of radial head with or without prosthetic replacement.

3) Non-union
Requires open bone grafting and internal fixation with excision of radial head.

Treatment

Close reduction is attempted first under general anesthesia.
For the next 3-4 weeks, X ray is done to check the progress of healing.
If unsatisfactory or re-displacement occurs, open reduction and internal fixation is done.


Galeazzi Fracture-dislocation


This condition is more common than it's counterpart (Monteggia F)
Defined as fracture of the distal third of radius with dislocation or subluxation of distal radio-ulnar joint.

Mechanism of injury : Fall on out-stretched hand

Clinical features

Prominence and tenderness over the ulnar styloid process.

Piano-key sign : The distal third of radius is ballotable

Instability of the distal radio-ulnar joint can be made prominent by supination and pronation of forearm.

Can be complicated as ulnar nerve injury (resulting in Ulnar claw hand)

Radiological features

Transverse of oblique fracture of the distal third of radius.
Dorsal displacement of the distal ulna or the distal radio-ulnar joint.


Complications

Main complication is mal-union, which limits supination and pronation of the forearm.

Treatment

Close reduction is not done (unless in children), since this fracture is unstable.
Instead, open reduction and internal fixation is done.


Colles' fracture

defined as transverse fracture of the distal radius just above the wrist at the level of cortico-cancellous junction, with dorsal displacement of distal fragment.

Mechanism of injury : fall on out-stretch hand

It is the most common osteoporotic-related fracture in the upper limb.
Hence, it is common among post-menopausal women.



Clinical features

Pain, swelling, deformity.
Palpation over distal radius : tenderness and irregularity.
Dinner fork deformity.
Radial styloid being leveled or situated proximal to the ulnar styloid.

Complications

1) Joint stiffness

Involving the fingers, wrist, elbow and shoulder.

2) Mal-union

Occurs usually unnoticed within the immobilisation cast.

3) Subluxation of the distal radio-ulnar joint

Resulting shortening of the radius, which made the ulnar styloid more prominent.
Hence, any movement of the wrist joint involving pronation/supination or ulnar deviation is restricted or is painful.

4) Carpal tunnel syndrome
5) Ruptured tendon of extensor policis longus
6) Sudeck's osteodystrophy

Colles' fracture is the commonest cause of this condition in the upper limb.
Characterised by pain, swelling of wrist, hand and fingers, and deformity.
There's diffuse tenderness, and the skin over it appears glazed, stretched.
Treated by physiotherapy.

Treatment

1) Undisplaced

Cast immobilisation for 6 weeks, applied below elbow towards the neck of metacarpals.
Hand is immobilised in functional position, with slight palmar flexion and ulnar deviation.

2) Displaced (with dinner fork deformity)

First, close manipulative reduction is done under anesthesia.
Ask your assistant to apply traction over the wrist joint by holding the patient's hand, and counter traction at the elbow joint.
Press over the dorsal aspect of deformity, at the same time try palmar-flexing, ulnar deviation, and pronating the hand.
After reduction, confirm that it's properly done by X ray.
Apply colles' cast.

3) Comminuted

Requires open reduction and internal fixation.