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

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

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

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.

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.

The assessment of the implants was done by a secondary center that was unaware of which the bearing type was in which patient.

In this group we continued with the conventional polyethylene, but added in the new type of head (oxidized zirconium)

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

Linear and volumetric wear were measured in the most recent radiographs using a computer software package (Polyware Rev. 5; Draftware).

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

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.

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Rames RD, Stambough JB, Pashos GE, Maloney WJ, Martell JM, Clohisy JC. Fifteen-Year Results of Total Hip Arthroplasty With Cobalt-Chromium Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years and Less. J Arthroplasty. 2019 Jun;34(6):1143-1149. doi: 10.1016/j.arth.2019.01.071. Epub 2019 Feb 5.