The influence of hydroxyapatite coating of external fixator pins on pin loosening and pin track infection: A systematic review

ObjectiveThe primary objective of this systematic review of published randomised controlled trials was to evaluate whether there was a clinical benefit in terms of pin loosening and pin track infection, or deep infection, associated with hydroxyapatite coating of external fixator pins. The secondary objective was to evaluate whether there was a clinical benefit in terms of loss of alignment or malunion associated with hydroxyapatite coating of external fixator pins.MethodsStudies included were identified by a PubMed search for relevant randomised controlled trials on the 20th of December 2007. A systematic review was performed.ResultsAll of the studies concluded that there was significantly less pin loosening in the HA-coated groups although the definition of loosening was based on different criteria. However, there was insufficient evidence to properly evaluate the clinical benefit in terms of the numbers needed to treat to avoid premature pin removal. There was also insufficient evidence to evaluate whether any clinical benefit is gained by using HA-coated pins with respect to deep infection and malunion.ConclusionA well designed large randomised controlled trial is required to determine the numbers needed to treat with HA-coated pins to reduce the incidence of clinically relevant pin loosening, axial deformity and pin track or deep infection.