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™ cups containing a 28mm-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. 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.

[Duplication of the complete lumbosacral spine. Apropos of 1 case]. / Duplication complète du rachis lombo-sacré. A propos d'un cas.

The rare case of a 6 year old child with spinal cord duplication and malformations is reported. The malformation was probably related more to a double monster context than to a notochordodysraphism.