Role of coatings and materials of external fixation pins on the rates of pin tract infection: A systematic review and meta-analysis

BACKGROUND: Infection at the pin tract is a frequent and feared complication of external fixators (EF). The type of pin material and coatings have been regarded as possibly influencing infection rates. Over the last 20 years, few prospective clinical studies and systematic reviews addressed the role of coated pins on the rate of pin site infection in human clinical studies. AIM: To assess the EF literature over the past 20 years on the clinical benefits of pins manufactured from varied materials and coating systems and their possible role in pin tract infection rates. METHODS: We performed a systematic review according to the PRISMA and PICOS guidelines using four scientific platforms: PubMed, LiLacs, SciELO, and Cochrane. We searched the literature for related publications over the past 20 years. RESULTS: A literature search yielded 29 articles, among which seven met the inclusion criteria. These studies compared stainless-steel pins and pins coated with hydroxyapatite (HA), titanium and silver. The pin tract infection definitions were arbitrary and not standardized among studies. Most studies included a low number of patients in the analysis and used a short follow-up time. Three meta-analyses were carried out, comparing stainless steel vs silver pins, stainless steel vs HA-coated pins, and titanium vs HA-coated pins. None of this analysis resulted in statistically significant differences in pin tract infection rates. CONCLUSION: Currently, no clinical evidence supports the advantage of EF pins manufactured with materials other than stainless steel or coated over uncoated pins in reducing the rates of pin tract infections. A standardized definition of pin tract infection in external fixation is still lacking.