The use of interpositional bone grafting for arthrodesis of the first metatarsophalangeal joint can be a technically challenging procedure. A fresh-frozen femoral head allograft can provide an appropriate graft for lengthening and ultimate fusion. It has been well-documented in published studies that larger grafts at this site increase the risk of complications. When the joint is resected in a “square” fashion, length is actually lost from the first metatarsal head. We present a technique using a reamer applied to 1 side of the graft and the first metatarsal head in a “cup-and-cone” fashion, thereby limiting the total length of the actual graft size. This technique allows for easy positioning and lengthening, increasing the chance of graft incorporation at the fusion sites.