Most knee implants have very similar designs, and traces its roots back to the 60's and early 70's to the hospital for special surgery in new york, where dr. Insall (orthopedist), and dr. Burstein (biomechanist) along with dr. Ranawat (orthopedist) invented the insall-burstein knee that is used world wide.
Many refinements in design and materials have been made of the years. Instrumentation to implant
knees surgically also have improved. Your surgeon will choose the best implant for you based on age, gender, problem at hand etc. Its best to leave implant choice to the better judgement of the surgeon.