Broken Matchmaking?

I feel like the game matchmaking is broken or maybe I'm just unlucky. I do fairly well on most of my games, but I lose because of my teammates (I realize my mistakes and I do everything I can and I know when its my fault). Obviously If I was better I would be able to carry and I've done verything I can such as pinging go to drag or run, but these things prove useless to teammates. I feel as if each ranked games is whether you carry or lose, in rare occasions get carried, or get screwed because your teammates have no common sense.