RÉSUMÉ
PURPOSE: To analyze the characteristics of the interface membrane around loose Cementless Self-Cutting Titanium(CST) acetabular components. MATERIALS AND METHOD: The authors reviewed radiographs of one hundred and thirty-four hips which underwent total hip arthroplasty using Cementless Self-Cutting Titanium(CST) acetabular components, and performed histomorphological analysis on thirteen periprosthetic membranes which were taken out at the time of revision. RESULTS: After a mean follow-up of 82 months, thirteen hips(10%) underwent revision for acetabular loosening and migration. Histologic evaluation of the periprosthetic membranes showed evidence of abundant polyethylene and metal wear particles. The interface membrane was composed of a well vascularized loose connective tissue with macrophages. Polarized microscopy revealed numerous polyethylene wear particles. Ultrastructurally, numerous, variable-sized, irregular-shaped phagosomes containing electron-dense material were seen within the cytoplasm. Tissue digestion of the periprosthetic tissue eluted numerous polyethylene and metal particles. Energy dispersive X-ray spectroscopic analysis for these wear particles revealed high concentration of titanium and carbon component suggesting that the majority of the metal particles were titanium component and polyethylene particle. CONCLUSION: This study supports the concept that wear particles in total hip arthroplasty can be a strong stimulus for a foreign body response and that this reaction causes periprosthetic osteolysis and loosening.