Vioxx vs. Celebrex. One remains, the other is gone. Why?

I have taken Vioxx and Celebrex for arthritis, resulting from past surgeries. Both worked equally well for me. I understand that both medications contain the same ingredients. I also understand that there has been a heart-related death associated with Vioxx and it is no longer available. Question: If both medications do contain the same ingredients, then why was Vioxx taken off the market and Celebrex still remains?