It all depends upon the time of digestion, concentration of enzyme also. Ideally, you should take  the same number of femur heads for histological studies only, and few non-enzyme  treated. That is the only way you can be fully sure that which time and concentration will not affect subchondral bone.

I would think that any articular cartilage loss would be reflected by an upregulation of interleukin-1 and he RANK RANKLE cascade that follows. Synovial response with cytokine and chemokine upregulation will be important to following depending on how long this is going to on.

Very likely but depends on so many other factors as indicated above.