Study Comparing Marathon Polyethylene and Enduron Polyethylene Acetabular Liners Used in Total Hip Arthroplasty

Not Applicable

Completed

Conditions: Arthritis
Rheumatic Diseases
Osteoarthritis
Joint Diseases
Musculoskeletal Diseases

Interventions: Device: Total Hip Replacement

Registration Number: NCT01121146

Lead Sponsor: Anderson Orthopaedic Research Institute

Brief Summary: The purpose of the study is to determine whether crosslinked Marathon and standard Enduron polyethylene liners show differences in bone loss around the hip implant.

Detailed Description: Several institutions report very low wear rates with highly crosslinked polyethylene based on early clinical data. However, since bone loss typically appears after 5-year follow-up, the reduction in the incidence and extent of bone loss among total hip replacement patients with crosslinked Marathon liners, compared to those with standard Enduron liners, has not been as dramatic as the wear reduction. Despite the substantial reduction in wear that we observed at 5-year follow-up, the patients' perceptions of their outcomes remained similar among the Marathon and Enduron groups. This study will evaluate outcome at a minimum of 10-years after surgery among the same group of patients whose outcome was previously reported at 5-year follow-up. At 10-year follow-up, we anticipate that the reduction in wear associated with Marathon polyethylene will be associated with significant reductions in bone loss when compared to the Enduron polyethylene.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 236

Inclusion Criteria

(from original study)

-Elective total hip replacement patient

(from 10-year follow-up)

Consented to the original study.
Received a Duraloc 100 cup with either a crosslinked Marathon or standard Enduron liner.
Received an AML/Solution or a Prodigy stem with 28mm cobalt chrome femoral head.

Exclusion Criteria

(from original study)

-None

(from 10-year follow-up)

Patient did not receive device as specified in inclusion criteria.
Patient refused to consent to the 10-year follow-up.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Standard Enduron polyethylene	Total Hip Replacement	-
Crosslinked Marathon polyethylene	Total Hip Replacement	-

Primary Outcome Measures

Name	Time	Method
Incidence of Clinically Significant Osteolysis	Minimum 9-year radiographic follow-up	The incidence of clinically significant osteolysis was based on the number of unrevised THAs (total hip arthroplasties) with at least 1.5 square centimeters of pelvic and/or femoral osteolysis. Osteolysis was 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 were outlined on the anteroposterior pelvic radiograph and the area of the lesion was measured using Martell's Hip Analysis Suite software. Lesions were considered clinically important if the total area of osteolysis around a hip replacement was at least 1.5 square centimeters.

Secondary Outcome Measures

Name	Time	Method
Polyethylene Wear	Minimum 9-year radiographic follow-up	A single reviewer, who was blinded to the type of polyethylene liner, evaluated femoral head penetration among all unrevised hips with minimum 9-year radiographic follow-up using serial anteroposterior pelvic radiographs. Two-dimensional head penetration was determined for each follow-up radiograph relative to the immediate post-operative (nominal 6-week follow-up) reference view using Hip Suite Analysis version 8.0 with elliptical correction, a validated, computer-assisted technique. A linear wear rate was evaluated for each hip that had a minimum of three follow-up radiographs by 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 represented the steady-state linear wear rate. The steady-state linear wear rate data from all hips in a group was used to compute a mean polyethylene wear value.
Rate of Reoperation	10-year follow-up	The rate of reoperation was based on the number of reoperations in each group. Any additional surgery after a participant's initial hip replacement was considered a reoperation.
Patient Satisfaction	Minimum 9-year follow-up	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	Minimum 9-year follow-up	The Harris Hip Score measures outcome after hip replacement and is based on a scale from 0 (worst) to 100 (best).