Bone loss in primary total knee arthroplasty is rare compared to revision total knee arthroplasty. Bone loss encountered in primary arthroplasty is usually minor and mostly at the tibial surface. Since varus and flexion deformities are common, bone loss is most common in the posteromedial corner of the tibia. Bone loss may pose a problem in maintaining proper alignment of implants and a stable implantbone interface during surgery. When planning the treatment of bone loss, it is necessary to understand the etiology of the defect, its classification, the prosthesis to be used, all treatment options and surgical techniques. The aim of treatment; It should focus on preserving bone stock, anchoring the implant to strong structural bone, recreating an anatomical joint line, restoring flexion-extension stability.