We report a case of an acetabular fracture treated using a unidirectional porous β-tricalcium phosphate artificial bone (Affinos®) to surgically repair bone defects. An 82-year-old man sustained an acetabular fracture on the left side and presented with shock on arrival along with impaired vital signs and systolic blood pressure. Upon stabilization, we performed an open reduction and internal fixation. However, there were significant bone defects, which were then fixed using Affinos® (both blocks and granules), an artificial β-tricalcium phosphate bone with a porosity of 57% (pore size: 25-300 μm), characterized by a novel unidirectional porous structure. By 18 months postoperatively, the patient was able to perform stair climbing and absorption and bone fusion around the artificial bone were observed. Affinos® has a frost-like structure, which endows it with good tissue-invasive properties because of the capillary effect. Moreover, it has excellent osteoconduction capability. In this case, both Affinos® blocks and granules showed good affinity, absorption, and bone substitution. Further prospective studies are required to confirm our findings.