"But in the end, genetics, and the kind of cartilage you got from your parents, may play the biggest role. It is a little like buying tires, said Dr. Frederick M. Azar, chief of staff of the Campbell Clinic in Memphis and an official with the American Academy of Orthopaedic Surgeons. “You can get nice treads or you can get retreads,” he said."
Read the complete report: Why Do My Knees Hurt? (NYTimes 3.15.13)