Osteotomy around the knee preceding total knee arthroplasty (TKA) has long been perceived as a factor contributing to higher complication rates and increased risk of revision as compared with primary TKA. However, recent systematic reviews and large registry analysis have not been able to confirm this perception. Technical difficulties and slightly higher complication rates can be attributed to older lateral closing wedge tibial osteotomy techniques and are not reported for the more frequently performed tibial medial opening wedge techniques. In the first part of this article, the latest information on this topic will be summarized. The second part of this article deals with osteotomies combined with TKA. Guidelines will be presented for the treatment of osteoarthritic patients with large leg deformities or extra-articular deformities. We aim to describe the latest advances in preoperative planning techniques, including a stepwise decision-making process and a review of the literature about this topic.