A Study Comparing Ceramic-on-metal Articulation to Metal-on-metal Articulation in Cementless Primary Hip Arthroplasty

CCS is defined as: a. Total Harris Hip Score \> 80 points, and b. No acetabular or femoral revision or removal, and c. No pending acetabular or femoral revision or removal as defined in radiographic evaluation by: i. An acetabular radiographic assessment with all of the following: 1. Migration \< 4 mm, and 2. Change in angle of inclination \< 4o, and 3. Absence of osteolysis, and ii. A femoral radiographic assessment with all of the following: 1\. Subsidence \< 5 mm, and 2. Absence of osteolysis. The HHS including a series of questions answered by the patient and physical examinations recorded by a qualified health care professional covers four domains: pain (one item, 0-44 points), function and functional activities (seven items, 0-47 points), absence of deformity (one item, 0-4 points) and range of motion (one item, 0-5 points). To obtain a final score, the points are summed. The outcome score can be categorized as Excellent: 90-100; Good: 80-90; Fair: 70-80; Poor: \< 70

Time frame: 2 years post-operatively

Population: Due to a lack of radiographic evaluation data, the overall number of participants analyzed is smaller than the actual number enrolled.

Chromium and Cobalt concentrations in blood are measured in measurement unit nmol/L. The change from baseline analysis is presented.

Time frame: 6 months post-operatively, 1, 2, 3 and 5 years post-operatively

Population: Metal Ion analysis is only performed on a subset of the patients. Other than that, the number of participants fluctuates over time due to several reasons, such as missing visits or lost to follow-up or withdrawn from the study for any reason.

The Oxford Hip Score (OHS) is a patient-reported outcome measure that was developed to specifically assess the patient's perspective of outcome following THA. The OHS consists of twelve questions covering function and pain associated with the hip. To calculate the total score, each response is scored from 0 (worst outcome) to 4 (best outcome) and the sum of all 12 items is reported with a maximum of 48, representing the best score possible. The outcome score can be categorized as Excellent: \> 41; Good: 34 - 41; Fair: 27 - 33; Poor: \< 27.

Time frame: pre-operatively, 6 weeks post-operatively, 6 months post-operatively, 1, 2, 3, 4, 5 and 10 years post-operatively

Population: 2 patients were not included in analysis due to receiving a different articulation (not the study device). Other than that, the number of participants decreased over time due to several reasons, such as missing visits or lost to follow-up or withdrawn from the study for any reason.

Survival of the implant based on the removal or intended removal of the device. The percentage of patients that still have the implant 10 years post-operative is presented here.

Time frame: 10 years post-op

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC score) is a standardised patient reported outcome measure consisting of 24 items divided into 3 sub-sections: Pain (5 items), stiffness (2 items) and physical function or Activities of Daily Living; ADL (17 items). A higher score indicates a worse clinical outcome. The maximum score for each subsection is Pain: 20 - 0; Stiffness: 8 - 0; ADL: 68 - 0.

Time frame: pre-operatively, 6 weeks post-operatively, 6 months post-operatively, 1, 2, 3, 4, 5 and 10 years post-operatively

Population: 2 patients were not included in analysis due to receiving a different articulation (not the study device). Other than that, the number of participants decreased over time due to several reasons, such as missing visits or lost to follow-up or withdrawn from the study for any reason.