SNOWMASS, COLO. — Unicompartmental knee and total knee arthroplasties provide good results in carefully selected patients, said Dr. Thomas S. Thornhill, chairman of orthopedic surgery at Brig-ham and Women's Hospital in Boston, at a symposium sponsored by the American College of Rheumatology.
UKA is indicated for degenerative arthritis in patients who are not good candidates for osteotomy or total knee replacement regardless of age. UKA might be the first option to consider in a younger patient because “it's much easier to convert a [UKA] to a total [knee arthroplasty] than a total to another total,” he said.
He estimates that the revision rate for UKAs at his facility is about 1% per year. Most problems are related to wear and progression of disease in the lateral compartment. UKA can be performed with a small incision, involves a shorter hospital stay, lower cost, and more rapid rehabilitation than does a total knee replacement.
In their defense, TKA procedures that are cruciate sparing have good to excellent results at 10–15 years. The major problems with failure of TKA still are related to wear, loosening, and infection. “I would submit to you that most of these failures can be attributed to technical issues and patient selection,” said Dr. Thornhill.
The most common cause of failure is instability. Surgeons think they need to put the knee in loosely so it will bend and flex better. Instead the looseness creates shearing when the knee moves, he said.
Dr. Thornhill disclosed that he receives royalties from DePuy Inc. He also has received research grants from DePuy Inc., Biomet Inc., and Smith & Nephew.