Buried or exposed kirschner wires in paediatric upper extremity fracture fixation: A systematic review and meta-analysis of infection rates and complications.

Background: Paediatric upper limb fractures are commonly treated with Kirschner (K) wire fixation, which can be buried or left exposed. Although both techniques are widely used, controversy remains regarding infection risk, complications, and other clinical outcomes between buried and exposed K-wires. This systematic review and meta-analysis aimed to compare infection rates and secondary outcomes between buried and exposed K-wires in paediatric upper limb fractures located distal to and including the elbow, and proximal to the carpus.

Methods: A systematic review of the literature was conducted according to PRISMA guidelines, with searches performed across Medline, EMBASE, and the Cochrane Library up to July 2023. Studies were included if they directly compared buried and exposed K-wires in paediatric patients (under 18 years old) and reported on infection rates. Meta-analysis was conducted to compare overall infection rates. Pooled means were used to compare secondary outcomes. Bias was assessed using the ROBINS-I and RoB2 tools.

Results: Fifteen studies involving 1,854 participants were included. The meta-analysis showed that buried K-wires were associated with a significantly lower risk of overall postoperative infection compared to exposed K-wires (RR 0.33; 95 % CI 0.22 to 0.50; p< 0.001). The risk of deep infection requiring further surgery was 1.74 % in buried K-wires (95 % CI: 0.72 % to 2.75 %) and 2.07 % in exposed K-wires (95 % CI: 0.55 % to 3.59 %). Skin erosion was a common complication of buried K-wires, with a pooled mean rate of 13.0 %. Buried K-wires were associated with a higher likelihood of requiring removal in theatre (84.4 % vs. 4.2 %). Time to K-wire removal was longer in the buried group (10.9 weeks vs. 5.3 weeks). Re-operation and bone union failure rates were similar between groups.

Conclusion: Our systematic review and meta-analysis suggest that, while buried K-wires are associated with lower overall infection rates, the risk of deep infection is comparable between buried and exposed K-wires. Buried K-wires show higher rates of skin erosion and increased need for removal in theatre. Given these findings, exposed K-wires offer a safe and more cost-effective option for paediatric upper limb fracture fixation. Further studies are needed to assess patient-reported outcomes and environmental impacts.