Metal-on-Polyethylene Bearing Versus Ceramic-On-Ceramic Bearing In Total Hip Arthroplasty Intermediate Outcomes

Objective:Comparing middle-term clinical outcomes between Metal-on-Polyethylene bearing and Ceramic-on-Ceramic bearing surface in primary total hip arthroplasty (THA).Methods:A consecutive series of192primary non-cement total hip arthroplasties were performed in167patients. Except18cases of lost follow-up and3cases of deaths, there were146patients(172hips) available for final follow-up. All cases were divided into two groups (metal-on-polyethylene, MP; ceramic-on-ceramic, CC) according to the bearing surface. There were82patients (91hips) in MP group and64patients (81hips) in CC group. All patients were evaluated clinically and radiographically in a minimal follow-up duration of60months. Results:The Harris hip score showed obvious improvement in both groups compared with before operation (from47.8points preoperatively to88.5at the last follow-up, P＜0.01, MP group; from43.0points preoperatively to90.2at the last follow-up, P＜0.01, CC group). The Harris hip score had no significant difference between the2groups (P＞0.05). The5-year survival rate of prostheses was97.5%in CC group, and96.7%in MP group. Two hips were revised in CC group,1for fracture of pure ceramic liner and1for infection. But3hips were revised in MP group,1for acetabular shell loosening and migration,2for Femoral stem loosening and sinking. All other prostheses in CC group demonstrated no radiographic evidence of loosening. No periprosthetic osteolysis was found. The MP group,8patients became radiographic loosening,2of which demonstrated clinical loosening and had been revised finally. There were1case of dislocation in each groups. CC group had three cases of joint abnormal noise which was disappeared with non-surgical treatment. In the MP group,2patients (2hips) had weak thigh pain were found, no moderate or severe pain. In the CC group, no one had thigh pain.Conclusion:Our data showed that both metal-on-polyethylene bearing and ceramic-on-ceramic bearing surfaces have favorable outcome during middle-term follow-up. Compared with the MP group, CC group have some advantages in reducing osteolysis and loosening of the prosthesis.