Abstract
Background: Because of his tribologic properties Alumina on alumina bearing for THA is an attractive alternative to the the other traditional bearings surfaces and is used since about forty years, especially for young peoples. In order to resolve the problem caused by the rigidity of ceramic, the ceramic sandwich liner was introduced but some cases of ceramic fracture were reported.
The purpose of this study was to quantify and analyse these specific failure.
Methods: Between November 1999 and February 2008, a total of 353 CÉRASUL® (Zimmer, Winterthour, Suisse) liner acetabular component with a 28 mm alumina head were implanted in 298 patients. The results were reviewed at a mean of 3,5 years postoperatively with 6 patients loss to follow-up. Clinical follow-up with the PMA score and plain radiographic evaluation were performed. Based on Xray analysis, ceramic sandwich liner fractures were counted and analyzed.
Results: The mean PMA was 17,5 (10 to 18) at the final review
Kaplan-Meier survival curves were constructed for the outcomes of revision for any reasons and for ceramic liner fracture.
Seven fractures (2%) of ceramic sandwich liner were found and occured at a mean of 4,3 years after surgery without trauma. Fractures (20%) were the third diagnosis leading to the liner revision after dislocation (43%) and sepsis (26%). Neither patient related factors nor X ray position of the implants could be isolated as risk factor of liner fracture.
Discussion: Despite promising short term results in term of clinical and Xray analysis, ceramic sandwich liner is associated with a high rate of fracture. This complication have been already reported by other authors for different devices of the same concept ; instead of their conclusions, we were unabled to identify any risk factor of fracture. We hypothesised that repetitive impingement of the stem neck could be the first event of that disappointing complication. Due to this high rate of fracture we discontinued to implant ceramic sandwich liner for THA.
Correspondence should be addressed to: EFORT Central Office, Technoparkstrasse 1, CH – 8005 Zürich, Switzerland. Tel: +41 44 448 44 00; Email: office@efort.org
Author: Francois Gouin, France
E-mail: fgouin@chu-nantes.fr
