Surgeons can now customize artificial knee implants, prevent future revision surgeries

May 4 2010

Throughout the years orthopedic surgeons have learned that one size does not fit all when it comes to joint replacements. Because of advancements in technology, surgeons can now customize artificial knee implants and prevent future revision surgeries.

"In the next 10 years, we will see a more than 600 percent increase in revision knee replacement surgeries," said Dr. Kenneth Mathis, chairman of The Methodist Center for Orthopaedic Surgery in Houston. "Some of this is because we are doing them in younger patients, but the majority of cases I see for revision are from alignment and implantation errors."

Current alignment of the parts is done by referencing anatomical landmarks in the patient's knee at the time of surgery. It can be difficult to get the knee aligned properly in some cases due to deformity. Other times a surgeon's lack of experience can lead to a problem. A new technique using "custom cutting blocks" will give surgeons a better chance at aligning the joint properly, while giving the patient a longer-lasting, more effective implant.

"A CT scan is taken of the patient's leg before they come to the hospital. All the data points are analyzed by engineers and surgeons and the position of the implant is then decided by a computer," Mathis said. "The manufacturer then designs a custom cutting block that perfectly matches the shape of the patient's bone."

Mathis believes this holds great promise for narrowing the margin of error, relieving post-op pain and giving patients better balance of the ligaments and a good chance of resuming normal activities

"It's the same as aligning the wheels of a car," Mathis said. "You can get the wheel on the car, but the better it is aligned, the longer it will last and the more effective it will be."

Up until now, most knee replacements have come in standardized shapes and sizes. Patients either get number one, two or three, etc., without regard for the unique shape of some patients' bones. Mathis said this may also lead to revision surgery, if they do not have a typical shaped bone due to pain or soft tissue impingement. Patients can now get the cutting blocks as well as custom-made partial knee replacements.

"This customization of instruments and implants holds the promise of improved function and overall satisfaction for patients," Mathis said.

SOURCE Methodist Center for Orthopaedic Surgery in Houston