Articular surface implants with dimples

An implant system for a knee comprising a femur and a patella, said implant system comprising:

• a patella implant comprising:
• an implant body including:
• a bone facing surface configured to engage bone beneath an implant site formed in said patella;
• an articular facing surface configured to face towards an articulating surface of said femur, said articular facing surface having a non-anatomical shape;
• and
• a first and second dimple each being formed in said articular facing surface, said first and second dimple each having a load bearing surface configured to engage against said articulating surface of said femur, so as to increase a contact area between the articulating facing surface and the articulating surface of said femur;
• wherein said first dimple comprises a medial dimple and said second dimple comprises a lateral dimple configured to articulate against a medial facet and a lateral facet, respectively, of a trochlear groove of said femur, and wherein an area of said load bearing surface of said lateral dimple is larger than an area of said load bearing surface of said medial dimple, wherein said medial dimple and said lateral dimple are aligned along a common plane, wherein said common plane extends through a central region of said patella implant, wherein said common plane extends perpendicular to a direction of movement of said patella implant relative to said articulating surface of said femur, wherein at least one of said load bearing surface of said first and second dimple has a contour having a spherical dome shaped indentation and wherein at least one of said load bearing surface of said first and second dimple has a circular or an elongated oval shape.