Who's ramus was enlarged?
So is there a consensus on whether advancing both jaws sacrifices cheek concavity?
I agree with Lazlo, I think it's more a short face/long face thing. If you're short faced then vertically lengthening the jaws in theory could stretch the soft tissue more taut which is what gives that concave look in the first place. It will also lengthen the distance between the cheekbone and the jawline, the hollow area
But I haven't ever seen a person come out of surgery with that concave look unless they're already 90% there, so I wouldn't factor the possibility of losing it much into your decision..