Thursday, April 14, 2011

Ceramic materials reviewed for use in revised Depuy hips: the risk and rewards (3 of 3).

Wear rates with various replacement options when revising the Depuy hip:  ceramic options
Ceramic with ceramic or ceramic with poly
Ceramic bearings are available in 2 configurations: a ceramic femoral head (ball) with a polyethylene liner, or a ceramic femoral head (ball) with a ceramic liner. No one material is right for every patient. Only your surgeon can determine what's right for you.
Benefits
  • Reduced wear—improved lubrication and reduced friction
  • Performance—lower wear rates compared with polyethylene and metal
Limitations
Ceramic bearings may be:
  • More prone to fracture
  • Less forgiving in surgery
  • More likely to require the removal of greater quantities of healthy bone due to size limitations
  • More expensive than other bearing options
What do the Studies say about Ceramic hips? 

I am really interested in this type of material due to the very low wear debris over the long term with this material which of course causes the osteolysis.  I looked for some recent studies that reviewed the two issues that are known to be associated with the choice of ceramics:  more prone to fracture and dislocation and they emit a squeaky noise which is very bothersome to patients.

Study one:

Ceramic-on-ceramic total hip arthroplasty: incidence of instability and noise.

Schroder D, Bornstein L, Bostrom MP, Nestor BJ, Padgett DE, Westrich GH. Clin Orthop Relat Res. 2011 Feb;469(2):437-42. Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY10021, USA. Clin Orthop Relat Res. 2011 Feb;469(2):437-42.

Abstract

BACKGROUND: Alternative bearing materials in THA have been developed to reduce the incidence of osteolysis. Alumina-on-alumina bearings exhibit extremely low wear rates in vitro, but concerns exist regarding component impingement with the potential for dislocation and the occurrence of noise.
QUESTIONS/PURPOSES: We determined generation of squeaking and the relationship between squeaking and component position
CONCLUSIONS: At average 3 years follow up, 98% of ceramic-on-ceramic THAs did not require a revision, with 1.1% of hips having been revised for dislocation. Fewer than 2% of patients reported hearing an audible squeak, with no association found between component position and squeaking

The second study was interesting because it reviewed younger patient experience with the ceramic hip.  Generally, the metal and poly are first choices in hip replacements because they are purportedly “sturdier.”

Second Study:

Is alumina-on-alumina ceramic bearings total hip replacement the right choice in patients younger than 50 years of age? A 7- to 15-year follow-up study.

Boyer P, Huten D, Loriaut P, Lestrat V, Jeanrot C, Massin P. Orthop Traumatol Surg Res. 2010 Oct;96(6):616-22. Department of Orthopaedic Surgery, Bichat Claude-Bernard Hospital, North Paris Teaching Hospitals Group Nord, Paris Diderot University, 46, rue Henri-Huchard, 75877 Paris cedex 18, France.
INTRODUCTION: The alumina-on-alumina bearing couple in total hip replacement seems to be well adapted for young and active patients because of the absence of wear and the rarity of osteolysis. Over the long term, doubts persist as to the cementless cup fixation and on the functioning of this bearing system because of possible acoustic emissions during use.

HYPOTHESIS: In young subjects, the ceramic-on-ceramic bearing system limits wear and osteolysis occurrences, without exposing patients to serious side effects

MATERIAL AND MEHTODS: We report the results, with between 7 and 15 years of follow-up, for 32mm-diameter alumina-on-alumina implants in 76 patients younger than 50 years of age (83 hips),

RESULTS: Three cases of aseptic loosening of the cemented stems were observed as well as late migration of a Cerafit trellis™ cup in the 12th postoperative year. One ceramic insert broke in the eighth postoperative year. With the exception of one case, the patients, questioned retrospectively, reported no audible noise. With aseptic loosening (revised or not), the criterion for failure, the 12-year survival rate was 91±11% for the Cerafit trellis™ acetabular components and 91±16% for the cemented Osteal™ stems. The 9- and 7-year survival rates for the Cerafit HA™ cups and the Multicône™ stems, respectively, were 100%. Including all revisions for any cause, the 10-year survival rate of the entire series was 92%±11%.
DISCUSSION: Despite the absence of wear and osteolysis, the long-term survival of these implants in young subjects should be improved. Although longer follow-up is necessary to formulate a definitive opinion, we tend to prefer cementless stem and cup fixation in ceramic-on-ceramic bearing systems.

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I am due to go back to see my orthopedic surgeon as soon as all of the recommendations are in re the revision.  Currently, my surgeon is recommending that I just remove the metal liner and replace it with a poly liner.  Given the studies I’ve reviewed, I am wondering whether there is an option to remove the whole metal hip and replace it with ceramics.  I have no idea but it is a question for discussion

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