Cementless Hip Replacements can last 20 years

CHICAGO, Illinois—Revision hip replacements done with cementless metal cups can last up to 20 years, and cementless hip implants last even longer when used for primary hip arthroplasty, according to Craig Della Valle, MD, an associate professor of orthopedics at Rush University Medical Center in Chicago. Dr. Della Valle and colleagues reported 20-year-data on the durability of revision hip replacements done with cementless metal cups in the February issue of the Journal of Bone and Joint Surgery.¹

“There is a common misconception that hips last for 10 years, so younger patients should wait, but the durability is longer than 10 years and for most patients at 20 years there is still more than a 90% chance of the new hip holding up, and this is true for primary and revision surgeries,” Dr. Della Valle told MSKreport.com. “If you think about it, there are not a whole lot of things in your home that last 20 years.”

95% of cementless implants still fixed in place after 20 years

Dr. Della Valle and colleagues report that the Harris-Galante-1 acetabular metal shell, which is designed to allow a patient’s bone to grow into the implant, remained fixed in place in 95% of hip revision cases at a minimum follow-up of 20 years. Earlier generation implants used bone cement to secure the implant to the patient’s pelvis. These implants were associated with higher failure rates, particularly in revision patients. Dr. Della Valle said he is in the process of publishing similar data showing even better survivorship in a primary hip replacement cohort.

Of an initial cohort of 138 hips, researchers tracked 73 patients who were still living (77 hips) for 20 years or more. Of the 77 hips, 37 underwent both clinical and radiographic evaluation. Twenty patients had a clinical evaluation via telephone questionnaire and 21 underwent a repeat revision of the acetabular metal shell. Twenty of the 21 cementless cups were well fixed at the time of repeat revision and only one had become loose.

During the entire study period, 4 cups were identified as being loose by x-ray exam. For the entire cohort of 138 hips, the 20-year survivorship of the acetabular component was 95%, the researchers report.

Cementless implants not problem-free

There was an increased rate of revision surgery for wear-related complications when compared to 15-year-data on the same cohort. Ten patients, or 18%, had a complication related to wear of the bearing surface as opposed to 3% at 15 years.

“This is an operation that does show very good durability and this study should give orthopaedic surgeons faith that what we have been doing for the last decade does have durability,” he told MSKreport.com. “There are still problems though.”

The major long-term modes of failure highlighted by this study included bearing-surface wear, infection, and dislocation.

Surgeons are working on developing solutions for these problems. To stave off bearing-surface wear, surgeons now use cross-line polyethylene instead of standard polyethylene which seems to slow down the wear rate enough so that osteolysis becomes less common.

Infection is still a daunting problem, but smart implants that release antibiotics may help curtail infection rates following joint replacement surgery. Moreover, the use of a larger diameter femoral head may reduce the risk of dislocation after revision hip arthroplasty.

References

1. Park DK, Della Valle CJ, Quigley L, et al. Revision of the acetebular component without cement. J Bone Joint Surg Am. 2009;91:350-355.

Cementless Hip Replacements can last 20 years | Arthritis Information