Well, there ya go.
The (not shown) lack of articular cartilage is actually what’s preventing me from riding. The articular cartilage around the medial condyle” (the outside part of my femur) looks like this: 
It’s thought that the hole in the cartilage is catching and rubbing and snagging on the meniscus and causing tears.
The body, it’s a complex machine.
hey thanks for the nuun link, been meaning to get some, bummer on the gimp leg.