The invention relates to a base component for a tibial implant, comprising a lateral compartment (14), a medial compartment (12) and an anterior connection portion (16) which connects the lateral compartment (14) and the medial compartment (12) to one another at anterior. A portion (18) open to posterior is provided between the lateral compartment (14) and the medial compartment (12). The lateral component (14) and the medial component (12) each have a lower side and an upper side, with at least one of the lower sides being configured for the fastening of the base component to the tibia. A marginal web (22, 22') is formed at at least one of the compartments (12, 14), starting from the upper side, said marginal web forming a receiving shell for a meniscus component (30, 32) of the tibial implant together with the upper side of the compartment. The height of the marginal web (22, 22') in a posterior region is reduced with respect to other regions of the marginal web (22, 22') at at least one of the two compartments (12, 14). The invention furthermore relates to a tibial implant and to a knee prosthesis.