Comparing the cost of operations like joint replacement from country to country is truly like comparing apples to oranges. First of all, when costs are reported they may include all costs. This can include the surgeon, hospital, anesthesiology, drugs, and rehab. Other registries with collected data don't include the surgeon's fees.

There is a difference in costs and billing between private and public systems. National health care is available in some countries, but not all. University hospitals may receive more funding to help offset the more complex patients they see.

And finally, the cost of the implants used varies from country to country. Studies show that at a time when overall hospital costs have gone down, the price of the implants has gone up. Some hospitals are even buying implants by the case to help keep the cost down.

As the number of adults needing joint replacements increases, the total cost is going to go up and up. Finding ways to avoid joint replacements and especially revision surgeries is the next goal of many researchers.