A family of tibial prostheses sized for attachment to a proximal tibia, the family comprising: a plurality of tibial prostheses defining a plurality of prosthesis peripheries (200 X), each said prosthesis periphery defining: a centroid, an anteroposterior axis dividing said prosthesis periphery into a medial compartment and a lateral compartment; a posterior-medial distance extending from said centroid to a posterior-medial corner of said prosthesis periphery; a posterior-lateral distance extending from said centroid to a posterior-lateral corner of said prosthesis periphery; said plurality of prosthesis peripheries including: a small periphery defining said posterior-medial distance having a small posterior-medial extent and said posterior-lateral distance having a small posterior-lateral extent; and a large periphery defining said posterior-medial distance having a large posterior-medial extent larger than said small posterior-medial extent to exhibit a posterior-medial growth, said large periphery further defining said posterior-lateral distance having a large posterior-lateral extent larger than said small posterior-lateral extent to exhibit a posterior-lateral growth, characterised in that said posterior-medial growth is larger than said posterior-lateral growth. a plurality of tibial prostheses defining a plurality of prosthesis peripheries (200 X), each said prosthesis periphery defining: a centroid, an anteroposterior axis dividing said prosthesis periphery into a medial compartment and a lateral compartment; a posterior-medial distance extending from said centroid to a posterior-medial corner of said prosthesis periphery; a posterior-lateral distance extending from said centroid to a posterior-lateral corner of said prosthesis periphery; a centroid, an anteroposterior axis dividing said prosthesis periphery into a medial compartment and a lateral compartment; a posterior-medial distance extending from said centroid to a posterior-medial corner of said prosthesis periphery; a posterior-lateral distance extending from said centroid to a posterior-lateral corner of said prosthesis periphery; said plurality of prosthesis peripheries including: a small periphery defining said posterior-medial distance having a small posterior-medial extent and said posterior-lateral distance having a small posterior-lateral extent; and a large periphery defining said posterior-medial distance having a large posterior-medial extent larger than said small posterior-medial extent to exhibit a posterior-medial growth, said large periphery further defining said posterior-lateral distance having a large posterior-lateral extent larger than said small posterior-lateral extent to exhibit a posterior-lateral growth, characterised in that said posterior-medial growth is larger than said posterior-lateral growth. a small periphery defining said posterior-medial distance having a small posterior-medial extent and said posterior-lateral distance having a small posterior-lateral extent; and a large periphery defining said posterior-medial distance having a large posterior-medial extent larger than said small posterior-medial extent to exhibit a posterior-medial growth, said large periphery further defining said posterior-lateral distance having a large posterior-lateral extent larger than said small posterior-lateral extent to exhibit a posterior-lateral growth, characterised in that said posterior-medial growth is larger than said posterior-lateral growth.