Sandwich type ceramic liner fracture rate with the Atlas III™ socket: A study of 144 primary total hip replacements at a mean 74 months' follow-up

Introduction: Ceramic friction bearings have been proposed as a means of reducing wear in total hip replacement (THR). A sandwich composite concept including a ceramic bearing surface has been proposed as simplifying the modularity while matching metal-back cups with a polyethylene liner. It is not precisely known how frequently abnormal noise would occur during functioning of this type of implant, which moreover entails a risk of ceramic liner fracture. Hypothesis: Results with sandwich type ceramic liners are comparable to those with polyethylene liners, without risk of side effects (noise, fracture). Patients and methods: Clinical and radiological results of 144 cementless Atlas III (TM) cups containing a 28 mm-diameter polyethylene-ceramic sandwich type liner coupled to a ceramic Biolox Forte (TM) head were retrospectively analyzed at a mean 74 months' follow-up. Mean patient age was 59.4 years. Twelve patients were lost to follow-up. Femoral components comprised 61 ESOP (TM) anatomic stems and 71 BHS (TM) Corail stems. The radiologic study used Imagika (TM) software. Results: Global function scores were satisfactory: PMA score, 17.2 +/- 1.2 (range, 9 to 18); global Harris score, 93.6 +/- 3.1 (49 to 100). Global survivorship was 91.6% (95% CI: 86.34-96.9). Radioclinical analysis found seven liner fractures (5.3%) at a mean 32 months; all were non-traumatic and asymptomatic. Clinical risk factors for liner fracture were overweight, advanced age, dislocation, prosthetic impingement, increased postoperative offset was a radiologic risk factor. Discussion and conclusion: Despite these satisfactory radioclinical results, matching those for metal-backed implants containing a polyethylene liner, close surveillance is mandatory with this type of composite implant. The high fracture rate with ceramic-polyethylene sandwich type liners and relative lack of symptoms warrant caution in their use. Level of evidence: Level IV, retrospective or historic series. (C) 2011 Published by Elsevier Masson SAS.