H1 Hip Resurfacing Arthroplasty

This is a prospective, non-randomized, consecutive series, multicentre, observational study to evaluate the clinical outcome of ceramic-on- ceramic hip resurfacing arthroplasty using the ceramic, non-porous, non-cemented H1 Hip Resurfacing Arthroplasty. It includes a safety study followed by an efficacy study. Patients will be followed up for 10-years postoperatively. The primary aim is to confirm the safety of the H1 hip resurfacing prosthesis by demonstrating non-inferiority of the H1 device in terms of survivorship. The secondary is to evaluate superiority of the ceramic-on-ceramic H1 hip resurfacing prosthesis compared to Metal-on-Metal (MoM) hip resurfacing in terms of absence of metal ion release.The primary end point is revision for any reason.

Inclusion Criteria: * Patient requires primary hip arthroplasty due to degenerative joint disease (primary osteoarthritis, posttraumatic osteoarthritis, avascular necrosis, developmental hip dysplasia) * Patient is eligible for hip resurfacing arthroplasty: i.e. has sufficient bone stock at the level of the femoral head (\1/3 necrosis of the femoral head) or in general as in severe osteopenia or osteoporosis (Tscore \< -2.5 as measured with BMD) * At the time of enrolment, patient has one or more of the following arthroplasties that have been * Implanted less than 6 months before the current hip arthroplasty: * Contralateral primary total hip arthroplasty or hip resurfacing arthroplasty * Ipsilateral or contralateral primary total knee or unicondylar knee arthroplasty * Patient takes medications which potentially affect the bone such as corticosteroids and antimitotic medications. * Patient has a condition that may interfere with the hip arthroplasty survival or outcome (i.e. Paget's or Charcot's disease, vascular insufficiency, muscular atrophy, uncontrolled diabetes, moderate to severe renal insufficiency or neuromuscular disease) * Patient has a known alcohol or drug abuse * Patient has an immunosuppressive disorder * Patient has a malignant tumour, metastatic, or neoplastic disease * Patient has severe comorbidities or a limited life expectancy * Patient lacks capacity to consent * Patient has an emotional or neurological condition that would pre-empt his/her ability or willingness to participate in the study * Patient is not willing or able to sign an informed consent form * Patient pregnant or breast feeding * Patient is not able or willing to come to follow-up visits * In addition, the following exclusion criteria are applied to the 20 patients (Cohort 1 and Cohort 1.1) in the safety study in whom metal ion measurements will be performed, since those conditions may be associated with elevated metal ion levels and could complicate the interpretation of the metal ion results: * Patients who already received another joint replacement, hip, knee, shoulder, ankle. * Workers in the paint, diamond, leather or other industries producing Co or Cr dust. * Patients taking medication, vitamins or food supplements containing Co or Cr and not able or willing to discontinue those.