Clinical Trial: Marathon and Enduron Polyethylene at Long-Term Follow-up

Study Status: Enrolling by invitation
Recruit Status: Enrolling by invitation
Study Type: Interventional

Official Title: A Prospective, Randomized Clinical Study Comparing Marathon Polyethylene and Enduron Polyethylene Acetabular Liners Used in Total Hip Arthroplasty at Long-Term Follow-up

Brief Summary: The purpose of the study is to determine whether crosslinked Marathon and standard Enduron polyethylene liners show differences in survivorship due to wear-related revisions at minimum 14-year follow-up and every 5 years after.

Detailed Summary:

Several institutions have reported very low wear rates with crosslinked polyethylene based on early and midterm clinical data. However, since revisions associated with osteolysis typically occur after 10-year follow-up, the greatest benefits of the reduced wear associated with crosslinked polyethylene are expected to be reflected in lower revision rates for wear-related complications at long-term follow-up.

While crosslinking has proven to substantially reduce polyethylene wear during the first decade in vivo, characterizing the long-term clinical performance of Marathon polyethylene remains important because crosslinking is accompanied by a reduction in the ultimate tensile strength, fatigue strength, and elongation to failure of ultra high molecular weight polyethylene. As a consequence, concerns have been expressed about the potential for the liner fracture, in vivo polyethylene oxidation or accelerated wear at long-term follow-up, the effects of femoral head roughening over time and the bioreactivity of crosslinked polyethylene debris particles. Ultimately, the best way to address these concerns is in the context of well-controlled, long-term clinical outcome studies. This study will evaluate outcome at a minimum of 14-years after surgery among the same group of patients whose outcome was previously reported at 10-year follow-up. As part of our efforts to follow patients throughout their lives to obtain long-term outcome data, we will continue to obtain routine follow-up every 5 years from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years). Because we anticipate that the reduced incidence of wear and osteolysis will result in a lower incidence of revision surgery among the patients randomized to Marathon liners, implant revision for reasons related to we
Sponsor: Anderson Orthopaedic Research Institute

Current Primary Outcome: Survivorship [ Time Frame: At 15-year follow-up and every 5 years after from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years) ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

• Polyethylene wear [ Time Frame: At minimum 14-year radiographic follow-up and every 5 years after from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years) ]
  A single reviewer, blinded to the type of polyethylene liner, will evaluate femoral head penetration among all hips using serial anteroposterior pelvic radiographs. Two-dimensional head penetration will be determined for each follow-up radiograph using Hip Suite Analysis version 8.0 with elliptical correction, a validated, computer-assisted technique. A linear wear rate will be evaluated for each hip that has a minimum of three follow-up radiographs using a least-squares linear regression to calculate the slope of the best-fit line for the wear vector magnitude versus time in situ data. The slope from this regression will represent the steady-state linear wear rate. The steady-state linear wear rate data from all hips in a group will be used to compute a mean polyethylene wear value.
• Incidence of Clinically Significant Osteolysis [ Time Frame: At minimum 14-year radiographic follow-up and every 5 years after from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years) ]
  The incidence of clinically significant osteolysis will be based on the number of THAs (total hip arthroplasties) with at least 1.5 square centimeters of pelvic and/or femoral osteolysis. Osteolysis will be defined as an area of localized loss of trabecular bone or cortical erosion that was not apparent on the pre-operative or immediate postoperative radiograph. To obtain lesion sizes, the defects will be outlined on the anteroposterior pelvic radiograph and the area of the lesion will be measured using Martell's Hip Analysis Suite software. Lesions will be considered clinically important if the total area of osteolysis around a hip replacement is at least 1.5 square centimeters.
• Patient satisfaction [ Time Frame: At minimum 14-year follow-up and every 5 years after from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years) ]
  Patient satisfaction was quantified by asking participants to respond "yes" or "no" to the question, "Are you satisfied with the results of your hip operation?"
• Harris Hip Score [ Time Frame: At minimum 14-year follow-up and every 5 years after from the date of the patient's primary total hip arthroplasty for the duration of the patient's life or until revision of the polyethylene liner (estimated to be 25 years) ]
  The Harris Hip Score measures outcome after hip replacement and is based on a scale from 0 (worst) to 100 (best).

Original Secondary Outcome: Same as current

Information By: Anderson Orthopaedic Research Institute

Dates:
Date Received: July 21, 2015
Date Started: June 2015
Date Completion: December 2030
Last Updated: July 23, 2015
Last Verified: July 2015