Vitamin E-Diffused Highly Cross-Linked Polyethylene Liner

NCT ID: NCT02801019

Last Updated: 2016-06-15

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 70 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2008-06-30
• Study Completion Date: 2011-11-30

Brief Summary

Vitamin E incorporated highly cross linked polyethylene (E-XLPE) was developed to increase oxidative resistance of highly cross-linked polyethylene (XLPE) without affecting mechanical properties. The investigators evaluated this type of polyethylene in a randomized clinical study, using Radiostereometric Analysis (RSA). The objective of this study was to compare the early-term wear of E-XLPE to a compression annealed polyethylene liner (C-XLPE, ArComXL®). The clinical outcome at two years was not expected to be affected by the choice of polyethylene.

Detailed Description

First generation of modern highly cross-linked polyethylene (XLPE) was clinically introduced in 1998 and has in most countries become standard as bearing surface in total hip arthroplasty. Studies of these materials have shown significantly reduced femoral head penetration when compared to gamma sterilized conventional polyethylene.

Thermaly treating (melting or annealing) is often a part of the manufacturing process of highly cross-linked polyethylenes. The polyethylene is exposed to irradiation to achieve cross-linking and improve wear resistance. Cross-linking by irradiation increases the amount of free radicals in the material.These radicals must be eliminated or stabilized to avoid oxidative degradation over time.Thermal treatment improves oxidation resistance but potentially changes the mechanical properties of the polyethylene.

By annealing i.e. heat treatment under the melt temperature the material maintains better mechanical properties, but elimination of free radicals is suboptimal, which can lead to oxidation in vivo.Heat treatment of the polyethylene above the melt temperature will more effectively reduce or eliminate the amount of residual free radicals. This will increase oxidation resistance, but will negatively influence the mechanical properties of the material.

Due to these limitations new generations of cross-linked polyethylene materials have been developed. Introducing Vitamin E (α-tocopherol), a natural antioxidant into the material prevents oxidative degradation and stabilizes the free radicals found in irradiated polyethylene plastic. In laboratory tests, polyethylene liners with incorporated vitamin-E have demonstrated similar wear, greater strength and better resistance to oxidation compared with the first generation cross-linked polyethylene. Currently, there are only laboratory studies on vitamin E diffused polyethylene available.

The hypothesis in this study is that the early-term E-XLPE wear is low and comparable to a heat-treated XLPE. The investigators also hypothesize that implant fixation and clinical outcome at two years will be unaffected by the choice of polyethylene.

The investigators therefore evaluated the early bedding in and wear in an uncemented arthroplasty supplied with liners made of vitamin E diffusion doped XLPE (E1®, Biomet, Warsaw, IN, USA). In the control group the investigators used the same uncemented hip prosthesis with polyethylene liners manufactured to achieve high levels of crosslinking without sacrificing the mechanical strength and extinguish residual free radicals (ArComXL® , Biomet, Warzaw, IN, USA).

Conditions

Osteoarthritis

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: SUPPORTIVE_CARE
• Blinding Strategy: DOUBLE

Study Groups

E-XLPE

E-poly

Group Type: EXPERIMENTAL

E-poly

Intervention Type: OTHER

comparison of two different polyethylene plastic 0,04 mm at 3 months 0,06 at 2 years

ArComXL

Intervention Type: OTHER

comparison of two different polyethylene plastic 0,03 mm at 3 months 0,10 mm at 2 years

C-XLPE

ArComXL

Group Type: ACTIVE_COMPARATOR

E-poly

Intervention Type: OTHER

comparison of two different polyethylene plastic 0,04 mm at 3 months 0,06 at 2 years

ArComXL

Intervention Type: OTHER

comparison of two different polyethylene plastic 0,03 mm at 3 months 0,10 mm at 2 years

Interventions

E-poly

comparison of two different polyethylene plastic 0,04 mm at 3 months 0,06 at 2 years

Intervention Type: OTHER

ArComXL

comparison of two different polyethylene plastic 0,03 mm at 3 months 0,10 mm at 2 years

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• primary and certain subgroups of secondary osteoarthritis
• Patients aged 20-75 years

Exclusion Criteria

• inflammatory arthritis
• cortisone or chemotherapy treatment
• known osteoporosis or osteomalacia

• Minimum Eligible Age: 20 Years
• Maximum Eligible Age: 75 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Sahlgrenska University Hospital

OTHER

Sponsor Role: lead

Responsible Party

Bita Shareghi

PhD student

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Johan Kärrholm, Professor

Role: PRINCIPAL_INVESTIGATOR

Sahlgrenska University Hospital

Other Identifiers

Dnr 279-08

Identifier Type: -

Identifier Source: org_study_id