Comparison of uncemented total hip arthroplasty between metal on metal and ceramic on polyethylene bearing surfaces in young patients

Abstract

Reducing wear guarantees the longer survivorship of the implants by reducing the osteolysis and aseptic loosening. Thus, the need for improved bearing surfaces in THA has led to the development and study of alternative bearing materials. We retrospectively reviewed the clinical and radiographic results of the metal-on-metal and ceramic-on-polyethylene articulation by matched pair study. There were 28 hips in the metal-on-metal group and 28 hips in the ceramicon-polyethylene group. The average periods of follow-up were 111 months in the metal-on-metal group and 106 months in the ceramic-on-polyethylene group. The mean Harris hip score of the final follow-up was 94.5 points in the metal-on-metal group and was 96.1 points in the ceramic-on-polyethylene group. The mean linear and volumetric wear rate of ceramic-on-polyethylene group was 0.08 ± 0.02 mm/yr and 87.42 ± 6.17 mm3/yr, respectively. Both group showed the excellent clinical and radiographic result with rare radiolucency and osteolysis. But there were three hips showing the unexplained groin pain in the metal-on-metal group. Of these, one hip underwent the revision surgery due to the periacetabular osteolysis which showed the histological findings compatible to the delayed metal hypersensitivity. In conclusion, both the metal-on-metal and ceramic-on-polyethylene articulations are the excellent alternative bearings of the conventional total hip arthroplasty. But, the ceramic-on-polyethylene articulation was the safer option than the metal-on-metal articulation. Osteolysis resulting from polyethylene wear debris is one of the most common causes of implant failure in young, active individuals who undergo total hip arthroplasty. Reducing wear guarantees the longer survivorship of the implants by reducing the osteolysis and aseptic loosening. Thus, the need for improved bearing surfaces in THA has led to the development and study of alternative bearing materials. These alternative bearing surfaces include metal-on-metal, alumina ceramic-on-alumina ceramic, zirconia-on-polyethylene, alumina ceramic-on-polyethylene or cross-linked polyethylene. These articulations have great success in reducing wear by disusing the polyethylene or modifying the polyethylene property. But it has been reported that these articulations have various disadvantages becoming new concerns. Of these new articulations, we have experiences only in metal-on-metal and ceramic-on-polyethylene bearings. The purpose of this retrospective matched pair study was to compare the clinical and radiographic outcomes of the metal-on- metal and ceramic-on-polyethylene bearings in young patients.