The purpose of this study is to compare the performance and compare the wear characteristics of two polyethylene cup liners, Marathon™ and Enduron™, in the treatment of patients with hip joint disease requiring a total hip replacement. Patients who enter the study will be randomly allocated to one of the polyethylene cup liners, Marathon™ or Enduron™ and will be evaluated at regular intervals using clinical and x-ray assessments.

The original protocol intended to perform clinical assessment using the Harris Hip Score, Merle D'Aubigne score and UCLA Activity Level Rating at 6 months, 1 year, 2 years, 3 years, 4 years, 5 years and 10 years post-operative. Merle D'Aubigne score evaluation was removed per Amendment 2.

However, protocol-specified data collected included only the linear and volumetric wear and incidence and pattern of radiological signs at 10 years post surgery. Data collected outside of the protocol included Oxford Hip Score and SF-12 for mental and physical well-being at 10 years post surgery and revision for any reason.

Inclusion Criteria:

i) Male or female subjects, aged between 45 and 75 years inclusive.

ii) Subjects who are able to give voluntary, written informed consent to participate in this investigation and from whom consent has been obtained.

iii) Subjects who, in the opinion of the Investigator, are able to understand this investigation, co-operate with the investigational procedures and are willing to return to the hospital for all the required post-operative follow-ups.

iv) Subjects with non-inflammatory arthritis of the hip who require a primary hip arthroplasty and are considered by the Clinical Investigator to be suitable for a cemented femoral component and an uncemented acetabular component.

v) Subjects who have a Charnley C classification

vi) Subjects who have undergone a contralateral hip replacement within past 6 months

vii) Subjects with a poorly functioning contralateral hip replacement or one which has been identified as requiring revision

viii) The first hip replacement scheduled for subjects identified as requiring primary bi-lateral hip replacements which will not be conducted simultaneously (i.e. on the same day).

Exclusion Criteria:

i) Subjects who, in the opinion of the Investigator, have an existing condition that would compromise their participation and follow-up in this study.

ii) Women who are pregnant.

iii) Subjects who are known drug or alcohol abusers or with psychological disorders that could effect follow-up care or treatment outcomes.

iv) Subjects who have participated in a clinical study with an investigational product in the last month.