From what I'm reading, it appears that your angle was a bit steep and probably hit the shoulder blade on the edge and traveled a short distance there before the bone stopped it - that would explain the lack of penetration and the piece of cartilage you found. It would also tell me that the deer is still alive. I won't take a shot that is too close to my tree for that reason. You can easily miss one of the lungs and the angles aren't conducive to a great shot. Hitting the shoulder blade broadside and at less of an angle usually will give you a pass thru unless you catch the ridge running thru the middle of it. I would still make an extensive search, but I think the deer is hurt, but alive.