This article is more than 5 years old. Information may no longer be current.
Highly crosslinked polyethylene liners have less femoral head penetration after hip replacement
Click Here to Manage Email Alerts
Through radiostereometric analysis, researchers observed significantly less femoral head penetration among patients who underwent total hip replacement with highly cross-linked polyethylene liners compared with conventional ultra-high molecular weight polyethylene liners, according to study results.
The researchers randomly assigned patients undergoing total hip replacement to receive either a cementless cup with a titanium mesh surface or a tantalum trabecular surface and either a highly cross-linked polyethylene liner or an ultra-high molecular weight polyethylene liner. The researchers obtained radiostereometric analysis, SF-36 physical component summary, WOMAC index, University of California Los Angeles (UCLA) activity and Harris Hip Scores preoperatively, postoperatively, at 6 months and annually thereafter.
Results showed significant improvement in SF-36 physical component summary, WOMAC, UCLA activity and Harris Hip Score postoperatively among all patients. At 5 years, radiostereometric analysis examination showed significantly less median femoral head penetration for highly cross-linked polyethylene liners. From 1 year to 5 years, the researchers found a steady-state wear rate of 0.04 mm per year for ultra-high molecular weight polyethylene liners and of 0.004 mm per year for highly cross-linked polyethylene liners.
According to study results, 5-year follow-up showed a median migration of approximately 0.05 mm proximally for titanium cups and of approximately 0.21 mm for tantalum cups. – by Casey Tingle
Disclosures: Ayers reports having received grants from Zimmer. Please see the full study for a list of all other authors’ relevant financial disclosures.
Perspective
Back to Top
Robert T. Trousdale, MD
The study entitled Radiostereometric Analysis Study of Tantalum Compared with Titanium Acetabular Cups and Highly Cross-Linked Compared with Conventional Liners in Young Patients Undergoing Total Hip Replacement by Ayers et al. is a very well done, well-written study. The authors did a blinded, randomized, control trial comparing two different acetabular ingrowth surfaces (tantalum and titanium fiber mess) and highly cross-linked polyethylene liners vs. ultra-high molecular weight polyethylene liners. There were four groups with the above mentioned cohorts. The relatively novel aspect of this study is that they used very precise radiostereometric analysis as well as validated outcome measures.
The conclusion of this study is not novel, however. Most clinicians realize that both fiber mess and tantalum ingrowth surfaces appear to be reliable and durable at intermittent follow-up. Most clinical studies with both of these ingrowth surfaces have done extremely well.
The other factor that is not novel about this study, although they documented very precisely, was that the wear rates of the highly cross-linked polyethylene were better than the ultra-high molecular weight polyethylene liners. They documented this more precisely with the radiostereometric analysis technology. They found the femoral head penetration rate was 10 times lower in the highly cross-linked polyethylene group compared with the ultrahigh molecular weight polyethylene group.
This study, in a more precise fashion, adds on to the clinical knowledge base that highly cross-linked polyethylenes, at least at intermediate follow-up, appear to be reliable, durable and wear extremely well, even in young, active patients.
There are still many controversies that this study does not address; namely whether the counter surface should be ceramic or cobalt chrome. Furthermore, the exact head size that should be utilized remains cloudy.
Nevertheless, this is a beautifully done study using very sophisticated technology which further adds to the proof that an uncemented acetabular component with either tantalum or fiber mess appears to be reliable and highly cross-linked polyethylene appears to be the bearing surface of choice for most of our patients.
Click Here to Manage Email Alerts