Bone defects in primary total knee arthroplasty (TKA) are small and easy to treat. However, in revision TKA, severe bone loss occurs, which is challenging to manage. The treatment options for extensive bone defects include metal augments, mega prostheses, custom prostheses, massive autogenous bone grafts, and massive allogenous bone grafts (ABGs) [1]. The advantages of ABGs include their biological potential, biocompatibility, and bone stock restoration; moreover, ABGs’ versatility allows surgeons to sharpen the graft-to-host bone defect and avoid unnecessary host bone removal [[2], [3], [4], [5]]. Allogenous structural bone graft (ASBG) can be applied to extensive bone defects, and it was considered one of the most useful methods. There have been several studies on the application of ASBG in revision TKA. However, there are few reports on applying femoral condyle ASBG to treat femoral condyle defects involving the cortex [4,[6], [7], [8]]. This study reports three cases of femoral condyle allogenous structural bone grafting for extensive bone defects, including femoral condyle loss, in revision TKA.