Cementless Hip Implants Are Durable for at Least Twenty Years

A new study has found that despite the common perception that total hip replacements last only ten years, the devices are in fact extremely durable, even 20 years after surgery.

Researchers at Rush University Medical Center (Rush, Chicago, IL, USA) analyzed results for 124 hip replacements--out of 204 total hip replacements performed at Rush in the mid-1980s in a group of 184 patients ranging in age from 20 to 84 years--who were still alive 20 years or more after surgery (the findings were previously reported at 10 and 15 years). The results showed that in the in the 111 patients still alive since the previous report at 15 years post-op, five metal cup implants were found to be loose, or 4% of the 124 implants. Of the original 204 hip replacements, five cases, or 2.5% of the total, had failed. Two of these five implants were revised, but three were left intact because the patients did not suffer significant symptoms. However, in nearly 20% of the patients still living 20 years post surgery, the plastic lining of the metal shell had worn enough that repeat, but less involved, surgery was required or recommended. Younger age strongly correlated with a higher risk of wear-related problems. Also, with time, the number of surgical revisions has increased due to osteolysis (bone resorption) as a result of the body's reaction to debris created by wear and corrosion of the metal implants. The study was published in the May 2009 issue of the Journal of Bone and Joint Surgery (JBJS).

"Our results confirm earlier work done at Rush and at other institutions; that cementless acetabular components work very well and that long-term biological fixation can be obtained," said lead author Craig Della Valle, M.D., an orthopedic surgeon at Rush. "With time, the number of repeat surgeries due to wear and osteolysis has increased, as have the numbers of cases of osteolysis we identified radiologically. But with the newer, more wear-resistant bearing surfaces we are now using, we believe that fewer patients today will need revision surgery for these reasons."

In this ongoing study, the researchers have been following the Harris-Galante I acetabular component, a cementless, hemispherical, porous-coated acetabular component made of unalloyed titanium with holes for screws, manufacture by Zimmer (Warsaw, IN, USA). The component design was based on research work done by Professor Jorge Galante, M.D., former chairman of orthopedics at Rush and a coauthor of this study. Earlier-generation implants, which relied on special cement to secure the device to the patient's bones, had been shown to have higher rates of failure, particularly beyond ten years.

Related Links:
Rush University Medical Center
Zimmer