Acetabular Press-Fit, Metal-Backed Cups. Results At Five Years

Aim. The acetabular cups with a "metal-back" providing bone integration on the outside and support for a polyethylene articular liner in the inside are the most diffused acetabular systems for total hip replacement, with good results and long follow up. The aim of this study is to estimate in the mid-term a group of press-fit, metal-backed cups. Methods. One hundred and twenty-five patients, to whom a Trilogy (R) cup was implanted, have been followed clinically (HSS hip-scoring system) and radiographically for an average period of about 5.5 years. Results. All the patients had a statistically significant increase (P < 0.05) of all the clinical items of HHS form. Two cups have been revised (1.6%): one for aseptic loosening and the other for recurrent dislocation. The radiological exams showed progressive radiolucent lines only in a single case (the revised one) and no other sings of failure (loosening, fractures, mobilisation) for all the studied cases; in 14 cases heterotopic calcifications have been detected. Conclusion. This study shows that the Trilogy (R) cup has good clinical results at mid-term, with adequate initial mechanical stability to allow osseous integration and with general improvement for patient's functions. in consideration of the short follow-up, it is mandatory to continue the surveillance of the systems for an evaluation at long term, which is the actual gold-standard in total hip replacement.