DISTAL RADIUS FRACTURES IN ADULTS

Abstract

My talk concentrates on the practical management of wrist fractures in adults. The management of complications of wrist fractures and the management of fractures in children are covered by other speakers.

Epidemiology

Fractures of the distal end of the radius have been estimated to account for upwards of 1/6 of all fractures seen and treated in emergency rooms. Distal radius fractures are more common in women. Above the age of 50 years, 86% of wrist fractures are in women. Fractures increase in incidence in both sexes with advancing age, and usually result from a fall from level ground rather than from high energy trauma. 10% of adults older than 35 years will suffer a distal radius fracture in a 30 year period.

Historical

Up until the early 18^th century, it was thought that the injury that resulted from a fall on the outstretched hand was a dislocation and not a fracture. The first author to suggest that the injury was a fracture was probably JL Petit in 1783. Abraham Colles published his article in 1814 without having dissected a specimen showing a fractured wrist. Barton described the fracture associated with his name in 1838. RW Smith described extra-articular bending fractures of the distal end of the radius in 1847.

Classification

There are very many different classifications used to describe fractures of the distal radius. The Frykman classification (1967) has been widely used in the past. It concentrates on the involvement of the radioulnar joint. The classification system of AO is useful for documenting fractures that does produce 144 possible combinations. The classification by Fernandez (In: Fractures of the Distal Radius Fernandez and Jupiter, Springer 1995) concentrates on the mechanism of the fracture and enables correlation with the management of the fracture. It is the most useful classification when deciding exactly what to do.

Imaging

Plain radiographs are the mainstay of fracture management. Good quality AP and lateral views are essential. A lateral view with the forearm angled 20 degrees towards the tube gives a better view of the lunate fossa. Tomograms can be used to evaluate the joint surface in an intra-articular fracture but has been superseded by more sophisticated imaging. Uniplanar CT produced good images in 1 plain only. The reconstructed images in second plane were always of poor quality. Nowadays Spiral CT produces excellent images with rapid acquisition and low radiation dosage. MRI scanning has its use in evaluating soft tissue injuries and also injuries to the bone that have not caused a fracture, such as a “bone bruise”. Intraoperatively it is possible to arthroscope the wrist in order to guide fracture reduction. This should only be attempted by skilled wrist arthroscopists.

Anaesthesia

In the UK, haematoma blocks have become the standard method of anaesthesia in the emergency room when manipulating fractures of the wrist. The degree of anaesthesia is somewhat unpredictable and the failure to achieve a complete anaesthesia leads to poor reductions.

Intravenous regional anaesthetic (Biers block) used to being the main form of the anaesthesia in British emergency rooms. The technique requires two doctors and was going out of fashion even before the manufacturers of Prilocaine withdrew the preservative-free formulation generally used for Biers blocks.

Axillary block anaesthesia is commonly used in the operating room but is less so in the emergency room.

General Anaesthesia is my preference for patients undergoing more than just simple manipulation.

Operative techniques

Surgeons should not limit themselves to only performing one method of stabilisation. They should be able to perform all forms. They should plan surgery in advance and should have the facility to adopt an alternative technique intraoperatively should this prove necessary.

If a patient requires a manipulation in a proper operating theatre using anything other than a haematoma block anaesthetic, then K-wires should be inserted for most fractures. There are many ways of inserting K-wires but my preference is for Kapandji intrafocal pinning.

External fixation can be used for many types of intra-articular fractures using the principle of ligamentotaxis. Most fixators are applied bridging the joint. If not put on with excessive distraction, stiffness is not usually a problem. McQueen has published on the application of nonbridging fixators which certainly has some clinical indications. In the older patient, the use of bone graft should always be considered to fill the defect left the following elevation of a fracture. The alternative is to use synthetic bone graft substitutes such as Biobon^®. Sometimes it is necessary to combine external fixation with supplementary K-wires.

Internal fixation

The volar approach through the terminal part of the Henry approach is relatively straightforward with low morbidity. This is used to apply volar buttress plates.

The distal radius is approached dorsally through incisions between the extensor compartments. The routine application of dorsal plates is favoured by some. However there is considerable morbidity associated with even the modern low profile plates such as the Pi plate. Tendon rupture is a particular problem. The plate usually has to be removed once the fracture has united. An approach between the fourth and fifth extensor compartment is useful in elevating the lunate facet prior to K-wire or screw fixation. Limited internal fixation using cannulated screws is useful in stabilising major fracture fragments such as the radial styloid.

As with any other fracture, the management of distal radius fractures is determined by the biology of the patient, the configuration of the fracture and the ability of the surgeon. The biggest errors come from considering all distal radius fractures as one, or applying one management protocol to all fractures.