Yes I feel BMP-7 is a powerful drug and just grows anything. There was a company advert which highlighted how excess cartilage from BMP7 had to be removed from the joint (in animal study), but thats the power if it growing tissue. I suppose the trouble in an OA joint is in some parts we have bone where we want cartilage and it may cause excessive bone growth in these areas. Perhaps with surgical intervention, i.e microfracture it may come into it's own, but again just an opinion