Arthrodesis of the first metatarsocuneiform joint: a comparative study of fixation methods.

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.