We are unable to recommend for or against a time threshold for reduction of displaced pediatric supracondylar fractures of the humerus without neurovascular injury.

Rationale
The timing of treatment of displaced pediatric supracondylar humerus fractures is an important practical concern. The advisability of urgent/emergent treatment is often weighed against the availability of a surgeon, access to an operating room, and the relative safety of anesthesia.  Six low quality studies with moderate applicability were identified.

All studies took a continuous variable (time to treatment) and defined early versus late treatment.  Early treatment was described as being within eight hours of injury in four studies and two used a twelve-hour cut-off (Table 44). While the time of an individual's presentation to the hospital is often well documented in the medical record, the time of injury is often estimated.  Such uncertainties may affect the quality of conclusions in these studies.

Five of seven critical outcomes identified by the work group were reported in the studies.  Four outcomes (compartment syndrome, cubitus varus, operative time, and need for reoperation) were not reported to be significantly different between early and late treatment groups in any of the studies.

One outcome, the need for open reduction, was reported in all six studies. Carmichael and Joyner, Iyengar, et al. and Sibinski, et al. reported no difference between early and late treatment groups. Gupta, et al. and Walmsley, et al. indicated an increased rate for open reduction in the delayed group, while Mehlman, et al. showed a decreased rate for open reduction with later treatment. The indication for open reduction is subjective and may therefore vary considerably. Without consistent, objective criteria for the requirement for open treatment, it is difficult to assess the results of the studies. Furthermore, these non-randomized retrospective studies are prone to selection bias.  More severe injuries may have been selected for earlier treatment, potentially confounding the comparative data.
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