Dr. Porth replaced my Knee nearly 20 years ago. I had a rare growth in the back of my knee called Synovial Osteochondromatosis. After three operations resulting in reoccurrence, Dr Porth replaced my Knee, and removing the Synovial lining to stop the Disease from reoccurring. Extensive rehab was necessary to retrain my knee to function. I am 73 years old now and was told my knee would last about 18 to 20 years. I had my knee scanned at 19 years, and was told it looked like it was just put in.