Does the IOFIX improve compression in ankle fusion?

BACKGROUND The new IOFIX is an intra-osseous fixation device comprising an "X-post" through which a lag screw passes to apparently improve force distribution across an arthrodesis. We conducted a novel human cadaveric study. Our null hypothesis was no difference in force exists in an ankle arthrodesis model stabilized with the IOFIX or a conventional single lag screw. METHOD In ten cadaver ankles a pressure transducer was compressed as an IOFIX and standard single lag screws were alternately compared. RESULTS The median average force created by the IOFIX was 3.95kg and 2.4kg for the single conventional lag screw (p⩽0.01). The IOFIX improved contact area across the arthrodesis with a median average of 3.41cm(2) compared with 2.42cm(2) in the lag screw group (p⩽0.03). CONCLUSION Our results suggest an IOFIX improves force distribution across an ankle arthrodesis compared with a single conventional lag screw.