The Articular Surface Replacement XL system (ASRXL) with metal-on-metal (MoM) of the articular surfaces was produced by DePuy Orhopaedics since 2003 for total hip replacement. In 2010 following the notification received from the National Joint Registry (NJR) of England and Wales concerning the excessive failure rate of the ASR system (approximately 13% at 5 years), the DePuy send the recall of the product. All operated patients were checked. We enrolled in our Followup 106 patients (51 males, 55 females, mean age 63.6) with a total of 107 implants (one is a bilateral case), subjected with clinical and instrumental investigations. The controls were performed annually; for the patients who presented positive clinical-instrumental condictions and values of Chromium (Cr) and Cobalt (Co)> 7 mg /l it has been proposed followup closer, every 6 months for the entire life of the implant. For the evaluation of the cases in our study, we used the following scales:
Clinical Score: Harris Hip Score (pain and functional limitation) Rx score: 0 normal; 1 bone resorbtion and mobilization Ultrasound score: 0 none 1 fluid collection <20 mm 2 fluid collection >20 mm 3 solid mass: metallosis Blood metal levels of Cr-Co (μg/l = parts per billion = ppb) Normal < 3 ppb Alert 3–7 ppb Pathological >7 ppb The analysis of ionemia was made at the Clinical Chemistry at Charing Cross Hospital in London.INTRODUCTION
MATERIALS AND METHODS
