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Vitamin E-Diffused Highly Cross-Linked Polyethylene Liner

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ClinicalTrials.gov Identifier: NCT02801019
Recruitment Status : Completed
First Posted : June 15, 2016
Last Update Posted : June 15, 2016
Sponsor:
Information provided by (Responsible Party):
Bita Shareghi, Sahlgrenska University Hospital, Sweden

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.

Condition or disease Intervention/treatment Phase
Osteoarthritis Other: E-poly Other: ArComXL Not Applicable

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).

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 70 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Supportive Care
Official Title: Wear and Creep of Vitamin E-Diffused Highly Cross-Linked Polyethylene Liners Randomized Radiostereometric Study of 70 Hips Followed for 2 Years
Study Start Date : June 2008
Actual Primary Completion Date : November 2011
Actual Study Completion Date : November 2011


Arm Intervention/treatment
Experimental: E-XLPE
E-poly
Other: E-poly
comparison of two different polyethylene plastic 0,04 mm at 3 months 0,06 at 2 years

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

Active Comparator: C-XLPE
ArComXL
Other: E-poly
comparison of two different polyethylene plastic 0,04 mm at 3 months 0,06 at 2 years

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




Primary Outcome Measures :
  1. Wear of vitamin E incorporated highly cross linked polyethylene [ Time Frame: up to 2 years ]
    Evaluation of the early bedding in and wear in an uncemented arthroplasty supplied with liners made of vitamin E diffusion doped XLPE in comparsion to annealed polyethylene liner, ArComXL.


Secondary Outcome Measures :
  1. Cup and stem translations [ Time Frame: up to 2 years ]
    Evaluation of cup and stem translations of vitamin E incorporated highly cross linked polyethylene compared to annealed polyethylene liner ArComXL liner.


Other Outcome Measures:
  1. Precision of the Radiostereometric analysis method [ Time Frame: Postoperatively, whitin 3 to 5 days after surgery ]
    The differences between the postoperative double-examinations was used to compute the precision for the method.



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Ages Eligible for Study:   20 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02801019


Sponsors and Collaborators
Sahlgrenska University Hospital, Sweden
Investigators
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Principal Investigator: Johan Kärrholm, Professor Sahlgrenska University Hospital, Sweden
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Responsible Party: Bita Shareghi, PhD student, Sahlgrenska University Hospital, Sweden
ClinicalTrials.gov Identifier: NCT02801019    
Other Study ID Numbers: Dnr 279-08
First Posted: June 15, 2016    Key Record Dates
Last Update Posted: June 15, 2016
Last Verified: June 2016
Additional relevant MeSH terms:
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Osteoarthritis
Arthritis
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases