Reader's note: This protocol is one of five reviews that will cover all surgical interventions for treating distal radial fractures in adults. Each review will provide updated evidence (from February 2003) for one of the several surgical categories that are presented together in the currently available review (Handoll 2003a). Following publication of the five reviews, Handoll 2003a will be converted to an 'umbrella' review summarising the evidence for surgical treatment for these fractures.

Description of the condition: distal radial fracture in adults
Fractures of the distal radius, often referred to as "wrist fractures", are common in both children and adults. They are usually defined as occurring within three centimetres of the radiocarpal joint of the radius, where the lower end of the radius interfaces with two (the lunate and the scaphoid) of the eight bones forming the carpus (the wrist). The majority are closed injuries, the overlying skin remaining intact.

In this review, we consider the treatment of distal radial fracture in adults only, in whom they are one of the most common fractures, predominantly in white and older populations in the developed world (Sahlin 1990; Singer 1998; Van Staa 2001). In women, the incidence of these fractures increases with age, starting at around 40 years of age. Before this age, the incidence is higher in men (Singer 1998). In contrast, between 60 to 94 years of age, females predominate. A recent multi‐centre study in the United Kingdom of patients aged 35 years and above with Colles' fracture (see below) reported an annual incidence of 9/10,000 in men and 37/10,000 in women (O'Neill 2001).

Young adults usually sustain this injury as a result of high‐energy trauma, such as a traffic accident. In older adults, especially females, the fracture more often results from low‐energy or moderate trauma, such as falling from standing height. This reflects the greater fragility of the bone, resulting from disuse or post menopausal osteoporosis. It has been estimated that, at 50 years of age, a white woman in USA or Northern Europe has a 15% lifetime risk of a distal radius fracture whereas a man has a lifetime risk of just over two per cent (Cummings 1985). More recent estimates (Van Staa 2001) of lifetime risk of radius or ulna fracture at 50 years of age are similar: 16.6% for women versus 2.9% for men.

Distal radial fractures are usually treated on an outpatient basis with estimates of around 20% of patients (mainly older people) requiring hospital admission (Cummings 1985; O'Neill 2001). This figure will include all people receiving surgery.

Classification
Surgeons have attempted to classify fractures by anatomical configuration or fracture pattern, to help in their management. Simple classifications were based on clinical appearance and often named after those who described them. In the distal radius, the term "Colles' fracture" is still used for a fracture in which there is an obvious and typical clinical deformity (commonly referred to as a dinner fork deformity) ‐ dorsal displacement, dorsal angulation, dorsal comminution, and radial shortening. The introduction of X‐rays and other imaging methods made it clear that the characteristic deformity may be associated with a range of different fracture patterns, which may be important determinants of outcome, and therefore the way in which treatment is conducted. For example, the fracture through the distal radius in a Colles' fracture may be extra‐articular (leaving the articular surface of the radius intact) or intra‐articular (the articular surface is disrupted, sometimes in a complex manner). Numerous classifications have been devised to define and group different fracture patterns (Chitnavis 1999). One of the most commonly used is that of Frykman which distinguishes between extra‐articular fractures and intra‐articular fractures of the radiocarpal and radio‐ulnar joints, and the presence or absence of an associated distal ulnar fracture (Frykman 1967). Another commonly used system is the AO (Arbeitsgemeinschaft fur Osteosynthesefragen) system (Muller 1991) which divides the fractures into three major groups: group A (extra‐articular), group B (simple/partial intra‐articular), and group C (complex/complete intra‐articular). These three groups are then subdivided, yielding 27 different fracture types. Other classification systems have attempted to link fracture type more directly with fracture management. For instance, Cooney 1993 proposed a 'Universal Classification' based on fracture displacement, articular involvement, reducibility (whether the fracture can be reduced; that is whether the bone fragments can be put back in place) and stability (whether, once reduced, the fragments will remain so).

Description of the intervention: external fixation
In the last century, most distal radial fractures in adults were treated conservatively, by reduction of the fracture when displaced, and stabilisation in a plaster cast or other external brace. Surgeons and other clinicians have recognised for many years that, particularly in older people with weakened bones from osteoporosis, the results of such conservative treatment are not consistently satisfactory (for an updated review of the evidence: see Handoll 2003b). This has resulted in attempts to develop other strategies involving surgery aimed at more accurate reduction and more reliable stabilisation of these fractures.

One such strategy is external fixation (Capo 2006; Fernandez 1999; Pennig 1996). Typically this is a closed, minimally invasive method where, in contrast to open surgery, the fractured bone is not exposed to direct view. Metal pins or screws are driven into bone, generally via small incisions of the skin and after drilling, on either side of the fracture. These pins are then held apart or fixed externally, such as by incorporation into a plaster cast or securing into the frame of an external fixator. The external component acts to stabilise or fix the reduced fracture. Fracture reduction or alignment of the bony fragments is generally achieved by closed means, often in the process of applying external fixation. Reduction may be assisted by the application of a percutaneously (through the skin) inserted wire used as a 'joy stick' to move the bony fragments back into place. There is considerable variety in the techniques (such as for pin insertion and placement) and devices used for external fixation. Some devices are 'non‐bridging' (of the wrist joint) in that the distal pins are placed in the distal radial fragment. In 'bridging fixators', the distal pins are placed in one or more metacarpal bones. Some fixators are linear or uniplanar, whereas others are multiplanar. In addition, some bridging fixators have an articulation (e.g. a ball joint) that allows limited wrist movement. The duration and extent of immobilisation with external fixation also vary. In some cases, external fixation may be augmented by additional methods of fracture fixation. In this review, we will include only trials using supplementary percutaneous pinning. This involves extra pins or wires being inserted through the skin and used to fix or support distal radial fragments.

Complications
Complications from this injury are diverse and frequent (Altissimi 1986; Atkins 1989; Cooney 1980). Some are associated with the injury itself. As well as concomitant injuries to soft tissues, fracture displacement can further compromise blood vessels, tendons and nerves, with median nerve dysfunction being the most common complication (Belsole 1993). Late complications include midcarpal instability and post‐traumatic arthritis which can occur several months or years after injury (Knirk 1986; Taleisnik 1984).

Complications can also result from treatment interventions and include residual finger stiffness, which may be due to faulty application of plaster casts (Gartland 1951), pin track infection, soft tissue injury including tendon rupture, and additional fractures from external fixation. Complex regional pain syndrome type 1, generally termed reflex sympathetic dystrophy (RSD), but also referred to as algodystrophy, Sudeck's atrophy and sometimes shoulder‐hand syndrome (Fernandez 1996) is a major complication requiring many months of physiotherapy to alleviate symptoms (pain and tenderness, impairment of joint mobility, swelling, dystrophy, vasomotor instability) in serious cases. The etiology of RSD is often unclear.

Why it is important to do this review
External fixation is one of the key methods for surgical fixation of distal radial fractures. A key question is whether it produces superior results to conservative treatment. The answer to this question is likely to depend particularly on fracture configuration and bone quality. The issue of what is the best method of external fixation will be addressed in a separate review.