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Surgeons debate effectiveness of ceramic-on-ceramic articulations for THA
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ORLANDO, Fla., USA – Ceramic-on-ceramic bearings for total hip arthroplasty have gained popularity in the past two decades due to low wear rates, high lubrication and scratch resistance, but as evidenced by presentations given, at the Current Concepts in Joint Replacement Winter Meeting, doubts remain in the orthopaedic community about whether ceramic-on-ceramic bearings truly offer better outcomes than standard bearings.
In an Orthopaedic Crossfire session, Carsten Perka, MD, PhD, of Berlin, and Robert L. Barrack, MD, of St. Louis, discussed ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) and whether the supposed benefits of using a ceramic material in the hip articulation were any greater than traditional, time-proven materials.
CoC may offer better outcomes
“This is an attractive option for the young and active patient. You have improved lubrication, excellent clinical results and this option is much more successful than other methods,” Perka said.
“The two major deal breakers in my mind are squeaking, which is not insignificant, and impingement, which does require very accurate placement,” Barrack said. “Although ceramics show promise for lower wear, substantial concerns persist. The question is, did these modifications address these concerns? I would submit to you that they did not.”
If the implantation does not lead to impingement, CoC bearings offer much better outcomes than the more traditional metal-on-metal (MoM) bearings. The ceramic offers superior hardness, produces less third body wear and is almost impervious to damage during implantation, Perka said.
“CoC has low wear. That is clear if you compare data. A lot of papers show CoC has the lowest wear rate of all bearings. Number two, it has optimum material properties. Ceramic-on-ceramic has excellent chemical stability, it has superior lubrication and the biocompetitivity is excellent. Ceramic is scratch-resistant and it is a proven technology. There are over 10 million implants in,” he said. “Also, bigger heads do not increase the wearing. We have seen the problem of the bigger heads, but we use more and more big heads to handle the problem of instability. For clinical data — long term survival — there are some data on that. After 20 years, the survival rate is 84.4%.”
Decline in CoC use
CoC THA articulations have certainly seen renewed interest among surgeons in the past 20 years, Barrack said, but usage peaked 7 years ago and has declined each year since. CoC implants can offer higher strength, lower wear and lower fracture rates when compared with traditional materials, but concerns have been expressed about the newer generation of ceramics, according to Barrack.
Delta Ceramics (DePuy Synthes; Warsaw, Ind., USA), a hybrid of alumina and zirconium in a composite, was designed to address the issues of material strength and reduced wear, as well as squeaking. However, he said some issues are still associated with this new material, which is more expensive than most other ceramics.
Paying more for an unproven product that does not outperform traditional, less expensive materials, is not a cost-effective measure, according to Barrack.
“Breakage continues to be a problem, especially with the liners. You have to get complete rim exposure and concentric placement in a patch of the liner. This makes ceramics difficult to use and the least compatible with [minimally invasive surgery] MIS surgery, and as we use smaller incisions it is hard to get these liners concentrically seating and impacted without chipping or breaking,” Barrack said.
Furthermore, Delta Ceramics also did not improve the issue of squeaking, he said. He noted in a case study, 69% of implants were silent and had grade 4 squeaking, meaning they were loud enough to cause embarrassment for the patient or make them fearful of attracting attention.
“Standard total hip replacement, which is metal on crosslinked [polyethylene], has improved even more than ceramic-on-ceramic. In 10 [years] to 15 years we cannot find a case of lysis, or much less revision even, in very young patients. The other deal breakers are the breaking and chipping, particularly the liner, and the squeaking. These components are less tolerant to suboptimal positioning, which leads to impingement and edge loading. Sadly, I think it is not quite ready for prime time,” Barrack said. – by Robert Linnehan
- References:
- Barrack RL. Paper #7. Perka C. Paper #6. Both presented at: Current Concepts in Joint Replacement Winter Meeting. Dec. 10-13, 2014; Orlando, Fla., USA.
- For more information:
- Robert L. Barrack, MD, can be reached at Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110 USA; email: barrackr@wustl.edu.
- Carsten Perka, MD, PhD, can be reached at Charité University Hospital, Humboldt University of Berlin, Schumannstrasse 20/21, Berlin D-10117, Germany; email: carsten.perka@charite.de.
Disclosures: Barrack receives royalties from, is a paid consultant to and receives other financial or material support from Stryker, Biomet, Medical Compression Systems, National Institutes of Health, Smith & Nephew and Wright Medical Technology. Perka receives an honorarium and royalties for consulting and teaching from Aesculap. He also receives a consulting fee from DePuy Synthes Joint Reconstruction and has intellectual property with Pluristem Therapeutics. He receives royalties, consulting fees and fees for speaking and teaching from Smith & Nephew. He receives fees for consulting and speaking from Zimmer.