From what I've read he has no cartilage left in either knee and the one is actually worse than the other. He is essentially bone on bone, which has to be excruciatingly painful. Several players had to retire due to the fact they had no cartilage left in their knees & Mo Vaughn had to have his knee replaced at age 35 I believe. So, how the hell is Bonds still stealing bases and playing the OF with no cartilage left in his knees? (Spare the steroid jokes). Just curious as hell as to how he is doing this.