Arthrodesis of the First Metatarsocuneiform Joint: A Comparative Study of Fixation Methods

Abstract

Background: The Lapidus bunionectomy is a popular procedure for severe bunion deformity where metatarsus primus varus is equal to or exceeds 15 degrees. We evaluated a new locking compression plate which may improve outcomes with the Lapidus procedure. Methods: Ten matched pairs of cadaver feet were used to compare the standard crossed 4.0-mm compression screw method of fixation to the LPS Lapidus plate. After performing the matched operations the cadaver constructs were stressed to failure using the INSTRON and Wavemaker software. Results: The LPS Lapidus plate load to failure was 108 Nm with a bending moment of 6.0 Nm. The crossed screw technique was inferior at 78 Nm with a bending moment of 4.4 Nm ( p = 0.02) Conclusion: Unlike other H-plates or locking plates, load to failure was higher with the Lapidus plate constructs. Clinical Relevance: The increased rigidity provided by these plates may help to minimize the risk of nonunion or malunion.