Arthritis, Joint Diseases, Musculoskeletal Diseases, Osteoarthritis, Rheumatic Diseases
Conditions
Keywords
Osteolysis, Polyethylene, Crosslinked Polyethylene, Total Hip Replacement, CT
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.
Interventions
DEVICETotal Hip Replacement
Comparison of Marathon and 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
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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. |
| 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). |
| 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? |
Countries
United States
Participant flow
Recruitment details
Starting in January 1999 for a period of 18 months, patients were enrolled from an orthopaedic clinic.
Pre-assignment details
Six subjects (6 hips) who had consented to participate were excluded from the study at the time of surgery because they did not receive a hip implant consisting of a 28-mm femoral head and a Duraloc 100 cup with a 4-mm lateralized liner due to intra-operative hip stability, leg length or cup fixation issues.
Participants by arm
| Arm | Count |
|---|---|
| Crosslinked Marathon Polyethylene Total Hip Replacement : Comparison of Marathon and Enduron polyethylene | 116 |
| Standard Enduron Polyethylene Total Hip Replacement : Comparison of Marathon and Enduron polyethylene | 114 |
| Total | 230 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Adverse Event | 2 | 11 |
| Overall Study | Death | 17 | 15 |
| Overall Study | Lost to Follow-up | 7 | 16 |
Baseline characteristics
| Characteristic | Crosslinked Marathon Polyethylene | Standard 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 |
| Region of Enrollment United States | 116 participants | 114 participants | 230 participants |
| Sex: Female, Male Female | 65 Participants | 57 Participants | 122 Participants |
| Sex: Female, Male Male | 51 Participants | 57 Participants | 108 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 2 / 116 | 11 / 114 |
Outcome results
Primary
Incidence of Clinically Significant Osteolysis
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.
Time frame: Minimum 9-year radiographic follow-up
Population: Minimum 9-year radiographs used to assess osteolysis were available for 79 unrevised hips with Marathon and 68 unrevised hips with Enduron polyethylene.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Incidence of Clinically Significant Osteolysis | 0 unrevised THAs |
| Standard Enduron Polyethylene | Incidence of Clinically Significant Osteolysis | 15 unrevised THAs |
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).
Time frame: Minimum 9-year follow-up
Population: Harris Hip Scores were evaluated for 74 unrevised hips with Marathon and 65 unrevised hips with Enduron polyethylene that had minimum 9-year follow-up and complete data to compute a score.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Crosslinked Marathon Polyethylene | Harris Hip Score | 88 score on a 100 point scale | Standard Deviation 14 |
| Standard Enduron Polyethylene | Harris Hip Score | 86 score on a 100 point scale | Standard Deviation 15 |
Secondary
Patient Satisfaction
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?
Time frame: Minimum 9-year follow-up
Population: Satisfaction rates were evaluated among 84 participants with unrevised hips who had Marathon and 70 participants with unrevised hips who had Enduron polyethylene. These participants had minimum 9-year follow-up and responded to the question about satisfaction.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Patient Satisfaction | 99 percentage of participants |
| Standard Enduron Polyethylene | Patient Satisfaction | 97 percentage of participants |
Secondary
Polyethylene Wear
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.
Time frame: Minimum 9-year radiographic follow-up
Population: At least 3 head penetration measurements evaluated with Martell's Hip Suite Analysis software were available for 76 unrevised hips with Marathon and 66 unrevised hips with Enduron polyethylene.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Crosslinked Marathon Polyethylene | Polyethylene Wear | .04 millimeters per year | Standard Deviation 0.06 |
| Standard Enduron Polyethylene | Polyethylene Wear | 0.22 millimeters per year | Standard Deviation 0.13 |
Secondary
Rate of Reoperation
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.
Time frame: 10-year follow-up
Population: All 116 hips randomized to Marathon polyethylene and all 114 hips randomized to Enduron polyethylene were included in the analysis population to determine the rate of reoperation.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Crosslinked Marathon Polyethylene | Rate of Reoperation | 2 THAs |
| Standard Enduron Polyethylene | Rate of Reoperation | 11 THAs |