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

SummaryIntroductionCeramic 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.HypothesisResults with sandwich type ceramic liners are comparable to those with polyethylene liners, without risk of side effects (noise, fracture).Patients and methodsClinical and radiological results of 144 cementless Atlas III™ cups containing a 28 mm-diameter polyethylene-ceramic sandwich type liner coupled to a ceramic Biolox Forte™ 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™ anatomic stems and 71 BHS™ Corail stems. The radiologic study used Imagika™ software.ResultsGlobal 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 conclusionDespite 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 evidenceLevel IV, retrospective or historic series.