In older people, a 'broken wrist' (from a fracture at the lower end of the two forearm bones) can result from a fall onto an outstretched hand. Surgery may be considered for more seriously displaced fractures. One type of surgery is external fixation, in which metal pins are driven into bone on either side of the fracture via small skin incisions and fixed externally. The external component holds the bony fragments in position while the bone heals. Most of the differences between methods of external fixation are a) in the characteristics and design of the external component and b) in the placement of pins. In some cases, the distal pins are placed into bones of the hand rather than the generally more fragile end of the fractured bone. This is bridging fixation, where the external component bridges and immobilises the wrist joint.
This review looked at the evidence from randomised controlled trials comparing different methods of external fixation.
Nine small randomised trials involving 510 adults with potentially or evidently unstable fractures, were grouped into five comparisons. The trials were too different to justify pooling of results. Only one trial used a best-practice method for preventing selection bias.
Two trials comparing a bridging (of the wrist) external fixator versus pins and plaster external fixation found no statistically significant differences in function or deformity. One trial found tendencies for more serious complications but less subsequent discomfort and deformity in the fixator group.
Three trials compared non-bridging versus bridging fixation, using external fixators. Two trials tested similar non-bridging fixators: one found no significant differences in functional or clinical outcomes, whereas the other found non-bridging fixation significantly improved grip strength, wrist flexion and anatomical outcome. The third trial found no significant findings in favour of multi-planar non-bridging fixation of complex fractures.
One trial using a bridging external fixator found that fixing the distal fracture fragment with an extra external fixator pin gave superior functional and anatomical results.
One trial found no evidence of differences in clinical outcomes for hydroxyapatite coated pins compared with standard uncoated pins.
Two trials compared dynamic versus static external fixation. One trial found no significant effects from the early 'dynamism' of an external fixator. The poor quality of the other trial undermines its findings of poorer results for dynamic fixation.
The review concluded that there is insufficient robust evidence to determine the relative effects of the different methods of external fixation.