Disclosed herein are systems, methods, and devices for providing a tibial implant including an anatomic stem that provides a close interface between the implant and surrounding bone. The stem varies in size, cross-sectional shape, or orientation from a proximal portion of the stem to the tip of the stem. The variation of the stem accommodates the variation of tibial anatomy into which the implant component is implanted. The stem provides resistance against rotation of the implant and reduces stress shielding effects by transmitting forces into surrounding bone. In certain implementations, the interface between the stem and bone is supplemented by fin extensions that extend outward from the stem and increase the contact between the implant and the surrounding bone structure.