The year 2013 will be a big one for healthcare. Enrollment in the health insurance exchanges that have made headlines in recent months will begin this fall, and there will be many other preparations for the full implementation of the federal health law next January.

Some analysts, however, say the real game-changer written into the Affordable Care Act wasn't health insurance exchanges, but Accountable Care Organizations, which they predict will see a big growth year in 2013.

Accountable Care Organizations (ACOs) are groups of local doctors and hospitals that  agree to work together to provide coordinated care to their patients.

They get bonuses if they keep healthcare costs for their patients down. Eventually, they will pay penalties if healthcare costs go up. The idea is to encourage and pay for preventive care and keeping people well, rather than just paying for running specific tests and procedures.

Richard Weil, a healthcare consultant with Oliver Wyman, predicts that the number of ACOs registered with Medicare will double or triple this year, up from their current 154. A recent report authored by Weil estimates that about 10 percent of the population is currently being treated by an ACO.

For patients, Accountable Care Organizations are designed to ensure primary care physicians, specialists, nurses and others who have a hand in your care are talking to each other and know which drugs and treatments you are receiving, even outside of their office. In many cases, 'care coordinators' help patients navigate through the health system.

Former Obama adviser and University of Pennsylvania medical ethicist Zeke Emanuel predicts that eventually, Accountable Care Organizations will decrease the importance of traditional insurance companies, or at least force them to take on a different role if they want to stay relevant.

"I do think that many of them are going to begin to ask, especially if the exchanges expand, why are they contracting with the insurance companies as the middle men, they could just go into the exchange themselves."

Emanuel, though, said this change won't happen overnight, but over the next decade or so.