This document summarizes Pro Osteon 500R, a bone graft substitute made of porous hydroxyapatite blocks. The blocks have an interconnected porosity similar to human cancellous bone, serving as a matrix for new bone ingrowth with comparable healing times to autogenous bone grafts. Using Pro Osteon 500R eliminates the risks and trauma of harvesting bone grafts from a second surgical site. The blocks are manufactured under FDA regulations to ensure high product quality. Sizes of blocks range from 1cc to 10.8cc volume. Clinical studies show Pro Osteon has equivalent healing to autogenous bone grafts in tibial plateau fractures.