Union Rates With the Use of Structural Allograft in Lapidus Arthrodesis: A Comparison Between Two Fixation Constructs

Although structural allograft has been previously described as acceptable practice for reconstructive foot and ankle surgery, results for an allograft bone wedge in Lapidus arthrodesis are unknown. Additionally, there is no consensus on the superiority of a single fixation construct in Lapidus cases. Our objective was (1) to report union rates for Lapidus arthrodesis with and without the use of an allograft bone wedge and (2) to determine if fixation construct impacts rates of union when using structural allograft. A review was performed for Lapidus cases with fixation constructs of 2 crossed compression screws (CS) and a medial locking plate with single transarticular screw (MPS), both with and without use of an allograft bone wedge. Inclusion required a CT scan to evaluate bony union. There was no significant difference in union rates (p = .41) between the use (90%) and the nonuse (97%) of an allograft bone wedge. Union rates were significantly different (p = .04) when comparing CS fixation (85%) and MPS fixation (98%). The comparative results between the fixation constructs highlight the importance of compression across the arthrodesis site as part of a robust fixation construct. Our findings demonstrate that the use of an allograft bone wedge in Lapidus arthrodesis may mitigate complications due to metatarsal shortening while providing satisfactory rates of union.