Although conventional high tibial osteotomy (HTO) primarily addresses coronal plane malalignment, the importance of sagittal plane alignment—specifically the posterior tibial slope (PTS)—cannot be overlooked in the setting of cruciate ligament insufficiency. Combined coronal and sagittal plane deformities are relatively rare and present unique surgical challenges. This narrative review summarizes the available literature and presents technical tips for managing complex biplanar deformities through a case‑based discussion of different techniques.