Evaluation of hydroxyapatite-coated Schanz screws in the Heidelberg external fixation system (HEFS)]

The use of monolateral external fixation systems for the correction of limb length and/or axial anomalies involves the implantation of Schanz screws in the long bones for periods of weeks or months. The loosening rate, which increases with duration of implantation, is a problem. In animal experiments/superior fixation and a reduced infection rate have been reported for hydroxyapatite-coated screws in comparison with conventional screws. We report on the clinical application of 59 hydroxyapatite-coated Schanz screws in 15 external fixation mountings. The performance of the screws was evaluated by clinical and radiological criteria. Infection was seen in 15 screws, necessitating the early removal of 6 of them. In patients with a second fixation system/the infection rate was lower, with infection developing in only 1 of 12 screws.