An Assessment of 4 Different Bearing Types in Hip Replacement Types to Analsye the Lowest Wear Rates of Polyethylene

Study Overview
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Brief Summary
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The aim of the study is to assess the ideal bearing surfaces in hip replacement by comparing 4 different combinations. In a hip replacement this means what the head and the socket liner are made of.

Detailed Description
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In hip replacements, arguably the most important thing for survivorship is what rubs against what. Traditionally surgeons used metal (Cobalt-Chrome) against a conventional polyethylene (plastic). More recently (around 15 years ago) a newer more dense type of polyethylene (called XLPE) had been developed and a new type of head called Oxidized Zirconium was also developed. In this trial, adults who were undergoing hip replacements were randomized assigned into one of the four groups: Group 1: old plastic vs metal head Group 2: Old plastic against Oxidized Zirconium Group 3: New plastic versus metal head Group 4 New plastic vs Oxidized Zirconium All patients were followed up for a minimum of 10 years to assess which group wore the most amount of polyethylene and which group had the best survival rate.

Official Title
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Randomized Control Trial of Four Bearing Surfaces in Primary Total Hip Arthroplasty in Patients Over the Age of 18 Years

Conditions
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Arthroplasty Complications, Hip Arthritis

Intervention / Treatment
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* Device: Highly Cross Linked Polyethylene and oxidized zirconium femoral head


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All adults with no history of cancer, infection of the hip and with the capacity to make informed consent for the trial Exclusion Criteria: those under the age of 18 and over 65. Those with a history of cancer and infection. Those without the capacity to make an informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Conventional Polyethylene versus metal head<br>This is the more conventional group bearing surfaces | Device: Highly Cross Linked Polyethylene and oxidized zirconium femoral head<br>* Differing bearing surfaces: Conventional polyethylene versus cobalt Chrome heads Conventional polyethylene versus Oxidized Zirconium heads Highly Cross-linked polyethylene versus Cobalt Chrome heads Highly Cross-linked polyethylene versus Oxidized Zirconium heads<br>* Other names: Varilast - from Smith & Nephew;|
| Experimental: Conventional Polyethylene versus oxidized zirconium head<br>This group uses the more conventional polyethylene against the newer head | Device: Highly Cross Linked Polyethylene and oxidized zirconium femoral head<br>* Differing bearing surfaces: Conventional polyethylene versus cobalt Chrome heads Conventional polyethylene versus Oxidized Zirconium heads Highly Cross-linked polyethylene versus Cobalt Chrome heads Highly Cross-linked polyethylene versus Oxidized Zirconium heads<br>* Other names: Varilast - from Smith & Nephew;|
| Experimental: Newer Cross linked Polyethylene metal head<br>In this group we continued with the conventional polyethylene, but added in the new type of head (oxidized zirconium) | Device: Highly Cross Linked Polyethylene and oxidized zirconium femoral head<br>* Differing bearing surfaces: Conventional polyethylene versus cobalt Chrome heads Conventional polyethylene versus Oxidized Zirconium heads Highly Cross-linked polyethylene versus Cobalt Chrome heads Highly Cross-linked polyethylene versus Oxidized Zirconium heads<br>* Other names: Varilast - from Smith & Nephew;|
| Experimental: Newer Cross linked Polyethylene versus oxidized zirconium head<br>In this group, we added both the new head and the new polyethylene | Device: Highly Cross Linked Polyethylene and oxidized zirconium femoral head<br>* Differing bearing surfaces: Conventional polyethylene versus cobalt Chrome heads Conventional polyethylene versus Oxidized Zirconium heads Highly Cross-linked polyethylene versus Cobalt Chrome heads Highly Cross-linked polyethylene versus Oxidized Zirconium heads<br>* Other names: Varilast - from Smith & Nephew;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Wear rates of polyethylene over 10 years | Linear and volumetric wear were measured in the most recent radiographs using a computer software package (Polyware Rev. 5; Draftware). | Over 10 years of wear rates | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Survivorship of implant combinations | Assess linear and volumetric wear to assess if those bearing surfaces require to be revised (exchanged) during the experimental period in one group more than the others | over 10 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hip arthroplasty, Tribology, wear