Hydroxyapatite-coated compared with stainless steel external fixation pins did not show impact in the rate of pin track infection: a multicenter prospective study

PURPOSE: Infection at the pin site remains the most common complication of external fixators (EFs). It is known that hydroxyapatite (HA)-coated pins increase bone adhesion and may lead to reduced rates of reported infections. The present study compares the rates of pin track infection associated with stainless steel and HA-coated pins. METHODS: This is a prospective, multicenter, nonrandomized, comparative intervention study among patients undergoing surgical treatment with EFs of any type between April 2018 and October 2021. Patients were followed up until the removal of the EF, or the end of the study period (ranging from 1 to 27.6 months). The definition of pin track infection was based upon the Maz-Oxford-Nuffield (MON) pin infection grading system. RESULTS: Overall, 132 patients undergoing external fixation surgery were included. Of these, 94 (71.2%) were male, with a mean age of 36.9 years (SD ± 18.9). Infection of any type (score > 1) was observed in 63 (47.7%) patients. Coated and uncoated-pin track-infection occurred in 45.7% and 48.5% of patients, respectively (P= 0.0887). The probability of developing infection (defined as a score ≥ 2) adjusted for comorbidities and follow-up time was not statistically higher among those who received uncoated pins compared to those who received pins coated with HA (odds ratio (OR) = 1.56, 95% confidence interval (95% CI): 0.67–3.67, p <0.05). CONCLUSION: In the present study, the external fixator pin infection rates were similar when using HA coating and standard steel pins. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00264-023-05717-w.