Philadelphia ? Wondering where to go for that hip replacement?

You could start at www.revolutionhealth.com, a new health site where you can compare surgeons’ rates of complications, look up death rates for the procedure at each local hospital, and even read patients’ comments about their care.

And it’s free.

Americans, of course, have been flocking to the Internet in search of health information for years – 113 million of them (80 percent of Web users) in 2006, according to the Pew Internet & American Life Project. Eight million people a day scour cyberspace for details on diets, diseases and doctors.

New Web sites seem to pop up almost daily touting new capabilities to help patients navigate a bewildering array of treatment options in an increasingly complex health system.

Revolution Health’s name notwithstanding, most experts see the movement as more of an evolution. And it’s still unclear whether the latest changes herald a new era of health consumerism.

“In one sense people are looking for a Zagat guide for health care, and the challenge is there may not ever be one,” says Don Liss, mid-Atlantic regional medical director for Aetna. “There is no single letter grade or number grade that can be applied to a doctor or hospital. Health care is much more nuanced than that.”

But plenty of sites are trying.

For-profit, nonprofit and government ventures are starting to rate and compare providers. Insurers are offering their subscribers access to Web tools that rate the quality of doctors and hospitals.

Through the U.S. Centers for Medicare and Medicaid Services’ “hospital compare” site, anyone can find out which local hospitals most often carry out practices that the medical community considers to be the best standard of care.

In the event of a heart attack, for example, where would you want to go?

The site can’t tell you that, but it can say what percentage of heart attack patients entering each hospital in the region were given aspirin – a simple act with proven benefits – and how they compare with state and national averages.

Go to www.hospitalcompare.hhs.gov, scroll down to enter your state and county, and then follow the instructions. You can “select all hospitals” and, for your next step, pick “heart attack.” From there you can choose among eight measures, including aspirin, to pull up colorful charts comparing how each institution performed.

Impressive as it sounds, these so-called process measures can be frustrating, often showing little difference between institutions. And while aspirin-on-arrival may be the recognized standard, it is not clear whether failure to give it translates into more deaths or complications.