A biomechanical optimization (BMO) prosthetic implant utilizes a thin cross-section of metallic material that is conformable. Preferably, the BMO prosthetic implant is conformable both at the time of implant in response to manipulation and fixation by the surgeon, as well as during the life of the implant in response to stresses and loads experienced by the implant and thereby communicated and responded to by living bone tissue. For most metallic alloys, the BMO prosthetic implant will have an effective cross-sectional thickness of 4 mm or less, and preferably 3 mm or less. In one embodiment, the BMO prosthetic implant is provided with one or more fins extending from the fixation surface(s) of the implant which preferably includes retaining structures, such as cross-pinned apertures or T-shaped edge ridge.