Freiberg says that the ability to model what a knee replacement would look like before it's performed could have advantages, although he notes that many surgeons prefer to actually see and measure the patient's anatomy before making decisions. He says that replacing a knee properly is a geometrically complex task that requires a great deal of precision, and companies have been looking for ways to eliminate guesswork with technology.

Along with the implants, ConforMIS also creates customized instruments, called iJig, which assist surgeons in placing the implant. Because the knee joint must be precisely aligned to function properly, surgeons use cutting and placement guides to ensure that any cuts to the bone are made at the correct angles so that the implant is placed in proper alignment. ConforMIS uses the imaging data from the patient to create disposable instruments that are calibrated to the patient's specific implant and anatomy. Lang says that the instrumentation will enable surgeons to perform the operation more quickly and easily, and it will also reduce time spent sterilizing reusable equipment.

ConforMIS announced today that it has raised $50 million in funding from investors worldwide in its latest round of fund-raising. Currently, the company has released three products for partial knee replacements, along with instrumentation, and it plans to make an implant available for a total knee replacement in 2010. Lang says that it takes about six weeks to create the implant, from imaging to shipping, and ConforMIS hopes to reduce that time to four weeks.

One concern about such a customized approach is the cost. As volume grows, the company hopes to provide its customized products at the same price as that of a standard implant.