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OsteoarthritisNCT01484002

Analysis of Crosslinked and Conventional Polyethylene Explants

An observational study of Osteoarthritis, run by Anderson Orthopaedic Research Institute at 2 sites in United States.

Unknown status

Status not confirmed. The sponsor has not verified this record for over two years, so it may be out of date.

Official record
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Trial summary

This retrospective study will investigate the changes that occur in ultrahigh molecular weight polyethylene (UHMWPE) implants that have been retrieved from joint replacement patients. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Osteoarthritis
What is being tested?
Total hip arthroplasty
Type of treatment
Medical device
How many people
60 participants
Where
2 sitesUnited States
Study dates
Dec 2011to Dec 2017
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: Crosslinked and conventional polyethylene liners terminally sterilized without gamma-irradiation will be used for this study. Specimens will be selected from the implant retrieval collection maintained by the Anderson Orthopaedic Research Institute.

Who may be able to join

  • Retrieved total hip arthroplasty liners maintained by the Anderson Orthopaedic Research Institute
  • Crosslinked or conventional liners terminally sterilized without gamma-irradiation

Who cannot join

  • Liners terminally sterilized with gamma-irradiation

Trial locations and contacts

2 sites in 1 country.

United States2 sites

  • Anderson Orthopaedic Research Institute

    Alexandria, Virginia, 22306

  • Orthopaedic Biomechanics and Biomaterials Laboratory at Massachusetts General Hospital

    Boston, Massachusetts, 02114

Other trials in United States

About this study

Official title: Collaborative Analysis of UHMWPE Explants: Conventional UHMWPE With No Radiation and Marathon

This retrospective study will investigate the changes that occur in ultrahigh molecular weight polyethylene (UHMWPE) implants that have been retrieved from joint replacement patients. Analysis techniques will include Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimeter (DSC) and crosslink density measurements. Crosslink density measurements will be evaluated as a function of distance away from the articular surface and the rim of the implant. Gel and hydroperoxide contents will also be evaluated. The objective is to characterize the in vivo and ex vivo changes that occur with cross-linked and conventional polyethylene bearings sterilized by methods that do not involve radiation. The investigators hypothesize that polyethylene absorbs lipids in vivo but experiences negligible oxidation or reductions in polymer crosslinking until it is explanted and stored at room temperature with access to ambient air.

Read the detailed description

For many years, gamma-irradiation in air was a common method for the terminal sterilization of ultrahigh molecular weight polyethylene (UHMWPE) materials used for joint replacement. A serendipitous byproduct of sterilization with gamma-irradiation was polymer crosslinking that tended to improve the wear performance of the polyethylene. During the 1990s, however, the orthopaedic community became aware that gamma-irradiation created free radicals within polyethylene, rendering the material susceptible to oxidative degradation. In view of this potentially deleterious effect, terminal sterilization methods using chemical surface treatments were developed to avoid free radical formation. To induce polyethylene crosslinking without residual free radicals, manufacturers also developed methods to crosslink the polyethylene followed by heat treatments to eliminate free radicals. These crosslinked materials were introduce during the latter part of the 1990s and clinical outcome studies among hip replacement patients have demonstrated substantially reduced wear at early follow-up intervals based on radiographic measurements. However, the long-term performance of crosslinked polyethylene is unknown and some investigators have expressed concerns related to in vivo degradation. Additionally, some crosslinked UHMWPE components have shown high levels of oxidation and chain scission after removal from patients and storage in air. Among these implants, it is unknown whether the oxidation and chain scission occurred during implantation or after the polyethylene was removed from the patient.

This study will characterize the material properties of polyethylene liners retrieved from hip replacement patients. The study population will include crosslinked and conventional UHMWPE liners that were terminally sterilized without the use of radiation. To quantify the potential effects of different storage methods, liners that were vacuum packed and frozen after retrieval and others that were stored at room temperature with access to ambient light and air following explantation will be included in the study population. Analysis techniques will include Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimeter (DSC) and crosslink density measurements. Crosslink density measurements will be evaluated as a function of distance away from the articular surface and the rim of the implant. Gel and hydroperoxide contents will also be evaluated. The goal of the analysis is to better understand the changes in polyethylene material properties that occur in vivo and ex vivo.

Conditions
Osteoarthritis
Being tested
Total hip arthroplasty
Keywords
Hip replacement, Crosslinked and conventional polyethylene, Oxidation, Crosslink density, Outcome
Medical subject headings
Osteoarthritis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Total hip arthroplastyDevice

    Also called DePuy Marathon crosslinked polyethylene, DePuy Enduron conventional polyethylene

    Replacement of a patient's native hip with an artificial implant featuring a metal-on-polyethylene articulation

Study groups in NCT01484002
Study groupRoleWhat they receive
Crosslinked polyethylene linersPolyethylene liners from joint replacements that were crosslinked and heat treated to eliminate free radicals.
Receives: Device: Total hip arthroplasty
Conventional polyethylene linersPolyethylene liners from joint replacements that manufactured from conventional UHMWPE and terminally sterilized by methods that did not involve gamma-irradiation.
Receives: Device: Total hip arthroplasty

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Oxidation levels

    Polyethylene oxidation levels will be quantified as a function of depth away from the articular and rim surfaces using Fourier Transform Infrared Spectroscopy (FTIR). Pre and post-hexane and nitric oxide (NO) exposed post-hexane thin sections will be analyzed.

    Measured: At an average of 5 years in vivo

Secondary outcomes (8)

  1. Absorbed lipids

    Absorbed lipids will be evaluated by determining the level of carbonyls before and after hexane extraction using Fourier Transform Infrared Spectroscopy (FTIR).

    Measured: At an average of 5 years in vivo

  2. Crosslink density

    Crosslink density will be evaluated using the gravimetric method on thin sections (~300μm) cut co-planar to the articular surfaces.

    Measured: At an average of 5 years in vivo

  3. Differential Scanning Calorimeter (DSC)

    Differential Scanning Calorimeter (DSC) will be used to determine the 1st and 2nd heats, and 1st cool crystallinity, peak melting/crystallization points.

    Measured: At an average of 5 years in vivo

  4. Hydroperoxides

    Hydroperoxides will be evaluated with FTIR by NO treatment after hexane extraction.

    Measured: At an average of 5 years in vivo

  5. Vinyl end-groups

    Vinyl end-groups will be evaluated with FTIR after hexane extraction to quantify chain scission.

    Measured: At an average of 5 years in vivo

  6. Trans vinylene (TVI) unsaturations

    Trans vinylene (TVI) unsaturations will be evaluated with FTIR after hexane extraction to determine radiation history and dose.

    Measured: At an average of 5 years in vivo

  7. Crystallinity

    Infra-red crystallinity will be evaluated with FTIR after hexane extraction.

    Measured: At an average of 5 years in vivo

  8. Gel content

    To quantify the extent of chain scission, gel content will be evaluated by measuring the non-extractable portion of the molecules using thin sections cut co-planar to the articular surfaces with a microtome and extracting the polyethylene chains from these sections in hot xylene.

    Measured: At an average of 5 years in vivo

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted2 Dec 2011 (estimated)
  2. Study startDec 2011
  3. Primary completionDec 2017 (estimated)
  4. Study completionDec 2017 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Retrospective
Enrolment
60 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT01484002
Sponsor's protocol ID
AORI2011-0101
Other IDs
MGH Agreement No: A208947
Status last verified
Jan 2017
First submitted
28 Nov 2011
Last updated
24 Jan 2017
Results posted
No
Data monitoring committee
No

Publications

  • Muratoglu OK, Wannomae KK, Rowell SL, Micheli BR, Malchau H. Ex vivo stability loss of irradiated and melted ultra-high molecular weight polyethylene. J Bone Joint Surg Am. 2010 Dec 1;92(17):2809-16. doi: 10.2106/JBJS.I.01017.

    PubMed 21123611

  • Bargmann LS, Bargmann BC, Collier JP, Currier BH, Mayor MB. Current sterilization and packaging methods for polyethylene. Clin Orthop Relat Res. 1999 Dec;(369):49-58. doi: 10.1097/00003086-199912000-00006.

    PubMed 10611860

  • Currier BH, Van Citters DW, Currier JH, Collier JP. In vivo oxidation in remelted highly cross-linked retrievals. J Bone Joint Surg Am. 2010 Oct 20;92(14):2409-18. doi: 10.2106/JBJS.I.01006.

    PubMed 20962191

  • Currier BH, Currier JH, Mayor MB, Lyford KA, Collier JP, Van Citters DW. Evaluation of oxidation and fatigue damage of retrieved crossfire polyethylene acetabular cups. J Bone Joint Surg Am. 2007 Sep;89(9):2023-9. doi: 10.2106/JBJS.F.00336.

    PubMed 17768201

  • Engh CA Jr, Stepniewski AS, Ginn SD, Beykirch SE, Sychterz-Terefenko CJ, Hopper RH Jr, Engh CA. A randomized prospective evaluation of outcomes after total hip arthroplasty using cross-linked marathon and non-cross-linked Enduron polyethylene liners. J Arthroplasty. 2006 Sep;21(6 Suppl 2):17-25. doi: 10.1016/j.arth.2006.05.002.

    PubMed 16950057

  • Malchau H, Bragdon CR, Muratoglu OK. The stepwise introduction of innovation into orthopedic surgery: the next level of dilemmas. J Arthroplasty. 2011 Sep;26(6):825-31. doi: 10.1016/j.arth.2010.08.007. Epub 2010 Oct 2.

    PubMed 20888183

Questions about this trial

What is this clinical trial studying?

An observational study of Osteoarthritis, run by Anderson Orthopaedic Research Institute at 2 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: status not confirmed, as of the sponsor's last update on 24 Jan 2017. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Results are not available in the source record.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Oxidation levels (time frame: At an average of 5 years in vivo). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT01484002, which also lists 6 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jan 2017.

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