Abstract: Nine small trials involving 510 adults with potentially or evidently unstable fractures, were grouped into five comparisons. The interventional, clinical and methodological heterogeneity of trials precluded data pooling. Only one trial had secure allocation concealment. Two trials comparing a bridging (of the wrist) external fixator versus pins and plaster external fixation found no 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. Of the two trials testing uni-planar non-bridging fixation, one found no significant differences in functional or clinical outcomes; 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 intra-articular fractures. One trial using a bridging external fixator found that deploying an extra external fixator pin to fix the 'floating' distal fragment 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 early dynamism of an external fixator. The poor quality of the other trial undermines its findings of poorer functional and anatomical outcomes for dynamic fixation. There is insufficient robust evidence to determine the relative effects of different methods of external fixation. Adequately powered studies could provide better evidence.

Plain-language summary: 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.