Arthritis, Joint Diseases, Musculoskeletal Diseases, Osteoarthritis, Rheumatic Diseases
Conditions
Keywords
Osteolysis, Polyethylene, Crosslinked Polyethylene, Total Hip Replacement, Marathon
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 description
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 wear will be our primary outcome measure at long-term follow-up.
Interventions
DEVICEHip Replacement with crosslinked Marathon polyethylene
Comparison of Marathon and Enduron polyethylene
DEVICEHip Replacement with noncrosslinked Enduron polyethylene
Sponsors
DePuy Orthopaedics
Anderson Orthopaedic Research Institute
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Healthy volunteers
Yes
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 continued follow-up.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Hips Surviving at 15 Years | 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) | Kaplan-Meier survivorship was calculated using revision for wear/osteolysis as an endpoint. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Polyethylene Wear | 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, evaluated femoral head penetration among all hips using serial anteroposterior pelvic radiographs. Two-dimensional head penetration was 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 was evaluated for each hip that had 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 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. |
| Incidence of Clinically Important Osteolysis Among Unrevised THAs | 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 important osteolysis is 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 and lateral radiographs. The area of the osteolysis 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 on either the AP or lateral view. |
| Patients Who Answered Yes to the Question, Are You Satisfied With the Results of Your Hip Operation? | 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? Because some patients had both of their hips included in the study, these patients responded to the question, Are you satisfied with the results of your hip operation? for their right and left hips. As a consequence, the Units Analyzed is reported as hips while the Number of Participants Analyzed reflects the number of patients. |
| Harris Hip Score | 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). The score includes assessments of pain, functional ability, deformity and range of motion. |
Countries
United States
Participant flow
Recruitment details
Beginning in January of 1999 and continuing over an 18-month period, patients at our institution were enrolled in a prospective, randomized, Institutional Review Board approved study to compare the outcome of THA using XLPE or CPE liners.
Pre-assignment details
All patients undergoing primary THA were eligible to participate in this study. A total of 226 patients (236 hips) consented to participate. Six patients (6 hips) were excluded at the time of their surgery because they were not implanted with the study components for reasons related to intra-operative hip stability.
Participants by arm
| Arm | Count |
|---|---|
| Crosslinked Marathon Polyethylene Total Hip Replacement using a crosslinked Marathon polyethylene liner | 114 |
| Crosslinked Marathon Polyethylene Total Hip Replacement using a crosslinked Marathon polyethylene liner | 116 |
| Non-crosslinked Enduron Polyethylene Total Hip Replacement using a noncrosslinked Enduron polyethylene liner | 111 |
| Non-crosslinked Enduron Polyethylene Total Hip Replacement using a noncrosslinked Enduron polyethylene liner | 114 |
| Total | 455 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Death | 32 | 33 |
| Overall Study | Incomplete follow-up | 17 | 15 |
| Overall Study | Liner revised | 3 | 19 |
Baseline characteristics
| Characteristic | Crosslinked Marathon Polyethylene | Non-crosslinked Enduron Polyethylene | Total |
|---|---|---|---|
| Age, Continuous | 62.5 years STANDARD_DEVIATION 10.6 | 62.0 years STANDARD_DEVIATION 11.1 | 62.3 years STANDARD_DEVIATION 10.8 |
| Body Mass Index (BMI) | 28.6 kilograms per square meter (kg/m^2) STANDARD_DEVIATION 5.5 | 27.9 kilograms per square meter (kg/m^2) STANDARD_DEVIATION 5.1 | 28.2 kilograms per square meter (kg/m^2) STANDARD_DEVIATION 5.3 |
| Race and Ethnicity Not Collected | — | — | 0 Participants |
| Sex: Female, Male Female | 65 hips | 57 hips | 122 hips |
| Sex: Female, Male Male | 51 hips | 57 hips | 108 hips |
| Weight | 186 pounds STANDARD_DEVIATION 47 | 180 pounds STANDARD_DEVIATION 40 | 183 pounds STANDARD_DEVIATION 43 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 32 / 116 | 33 / 114 |
| other Total, other adverse events | 0 / 116 | 0 / 114 |
| serious Total, serious adverse events | 4 / 116 | 19 / 114 |
Outcome results
Primary
Percentage of Hips Surviving at 15 Years
Kaplan-Meier survivorship was calculated using revision for wear/osteolysis as an endpoint.
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)
Population: All 230 total hip replacements randomized to crosslinked Marathon or non-crosslinked Enduron liners.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Percentage of Hips Surviving at 15 Years | 100 percentage of hips surviving at 15-years |
| Non-crosslinked Enduron Polyethylene | Percentage of Hips Surviving at 15 Years | 86 percentage of hips surviving at 15-years |
Comparison: Survivorship was evaluated using liner revision for wear/osteolysis as an endpoint using a Kaplan-Meier analysis.p-value: <0.001Log Rank
Secondary
Harris Hip Score
The Harris Hip Score measures outcome after hip replacement and is based on a scale from 0 (worst) to 100 (best). The score includes assessments of pain, functional ability, deformity and range of motion.
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)
Population: All hip replacements with minimum 14-year follow-up that had data to compute a Harris Hip Score.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Harris Hip Score | 96 units on a scale |
| Non-crosslinked Enduron Polyethylene | Harris Hip Score | 92 units on a scale |
p-value: 0.4Wilcoxon (Mann-Whitney)
Secondary
Incidence of Clinically Important Osteolysis Among Unrevised THAs
The incidence of clinically important osteolysis is 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 and lateral radiographs. The area of the osteolysis 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 on either the AP or lateral view.
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)
Population: Unrevised hips that had minimum 14-year radiographic follow-up and revised hips that had a pre-revision radiograph available for analysis.
| Arm | Measure | Value (COUNT_OF_UNITS) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Incidence of Clinically Important Osteolysis Among Unrevised THAs | 1 hips |
| Non-crosslinked Enduron Polyethylene | Incidence of Clinically Important Osteolysis Among Unrevised THAs | 28 hips |
p-value: <0.00195% CI: [0.006, 0.3]Fisher Exact
Secondary
Patients Who Answered Yes to the Question, Are You Satisfied With the Results of Your Hip Operation?
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? Because some patients had both of their hips included in the study, these patients responded to the question, Are you satisfied with the results of your hip operation? for their right and left hips. As a consequence, the Units Analyzed is reported as hips while the Number of Participants Analyzed reflects the number of patients.
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)
Population: All patients with minimum 14-year follow-up who responded to the question, Are you satisfied with the results of your hip operation?
| Arm | Measure | Value (COUNT_OF_UNITS) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Patients Who Answered Yes to the Question, Are You Satisfied With the Results of Your Hip Operation? | 53 hips |
| Non-crosslinked Enduron Polyethylene | Patients Who Answered Yes to the Question, Are You Satisfied With the Results of Your Hip Operation? | 48 hips |
Comparison: Since there were no patients with Marathon liners who were unsatisfied with the outcome of their hip replacement, a relative risk and the associated confidence interval could not be calculated.p-value: 0.48Fisher Exact
Secondary
Polyethylene Wear
A single reviewer, blinded to the type of polyethylene liner, evaluated femoral head penetration among all hips using serial anteroposterior pelvic radiographs. Two-dimensional head penetration was 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 was evaluated for each hip that had 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 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.
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)
Population: Hips with at least 3 serial anteroposterior pelvic radiographs that were revised or had minimum 14-year radiographic follow-up.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Crosslinked Marathon Polyethylene | Polyethylene Wear | 0.03 mm/yr | Standard Deviation 0.05 |
| Non-crosslinked Enduron Polyethylene | Polyethylene Wear | 0.25 mm/yr | Standard Deviation 0.16 |
p-value: <0.00195% CI: [0.17, 0.27]t-test, 2 sided