Trial Outcomes & Findings for Study Comparing Marathon Polyethylene and Enduron Polyethylene Acetabular Liners Used in Total Hip Arthroplasty (NCT NCT01121146)

Results Overview

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.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

236 participants

Primary outcome timeframe

Minimum 9-year radiographic follow-up

Results posted on

2014-11-05

Participant Flow

Starting in January 1999 for a period of 18 months, patients were enrolled from an orthopaedic clinic.

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.

Participant milestones

Participant milestones
Measure	Crosslinked Marathon Polyethylene Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Overall Study STARTED	116	114
Overall Study COMPLETED	90	72
Overall Study NOT COMPLETED	26	42

Reasons for withdrawal

Reasons for withdrawal
Measure	Crosslinked Marathon Polyethylene Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Overall Study Death	17	15
Overall Study Adverse Event	2	11
Overall Study Lost to Follow-up	7	16

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Crosslinked Marathon Polyethylene n=116 Participants Total Hip Replacement : Comparison of Marathon and Enduron polyethylene	Standard Enduron Polyethylene n=114 Participants Total Hip Replacement : Comparison of Marathon and Enduron polyethylene	Total n=230 Participants Total of all reporting groups
Age, Continuous	62.5 years STANDARD_DEVIATION 10.6 • n=5 Participants	62.0 years STANDARD_DEVIATION 11.1 • n=7 Participants	62.3 years STANDARD_DEVIATION 10.8 • n=5 Participants
Sex: Female, Male Female	65 Participants n=5 Participants	57 Participants n=7 Participants	122 Participants n=5 Participants
Sex: Female, Male Male	51 Participants n=5 Participants	57 Participants n=7 Participants	108 Participants n=5 Participants
Region of Enrollment United States	116 participants n=5 Participants	114 participants n=7 Participants	230 participants n=5 Participants

PRIMARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure	Crosslinked Marathon Polyethylene n=79 Participants Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene n=68 Participants Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Incidence of Clinically Significant Osteolysis	0 unrevised THAs	15 unrevised THAs

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure	Crosslinked Marathon Polyethylene n=76 Participants Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene n=66 Participants Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Polyethylene Wear	.04 millimeters per year Standard Deviation .06	0.22 millimeters per year Standard Deviation 0.13

SECONDARY outcome

Timeframe: 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.

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.

Outcome measures

Outcome measures
Measure	Crosslinked Marathon Polyethylene n=116 Participants Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene n=114 Participants Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Rate of Reoperation	2 THAs	11 THAs

SECONDARY outcome

Timeframe: 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.

The Harris Hip Score measures outcome after hip replacement and is based on a scale from 0 (worst) to 100 (best).

Outcome measures

Outcome measures
Measure	Crosslinked Marathon Polyethylene n=74 Participants Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene n=65 Participants Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Harris Hip Score	88 score on a 100 point scale Standard Deviation 14	86 score on a 100 point scale Standard Deviation 15

SECONDARY outcome

Timeframe: 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.

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?"

Outcome measures

Outcome measures
Measure	Crosslinked Marathon Polyethylene n=84 Participants Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene n=70 Participants Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Patient Satisfaction	99 percentage of participants	97 percentage of participants

Adverse Events

Crosslinked Marathon Polyethylene

Serious events: 2 serious events

Other events: 0 other events

Deaths: 0 deaths

Standard Enduron Polyethylene

Serious events: 11 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Crosslinked Marathon Polyethylene n=116 participants at risk Implanted with a metal femoral head and a crosslinked polyethylene liner.	Standard Enduron Polyethylene n=114 participants at risk Implanted with a metal femoral head and a non-crosslinked polyethylene liner.
Musculoskeletal and connective tissue disorders Dislocation and Reoperation	1.7% 2/116 • Adverse event data was collected throughout the duration of the study. The mean follow-up for the participants who were not revised and did not pass away within 9 years of their hip replacement was 10 years. Serious adverse events were collected by questioning study participants and reviewing medical records. The denominator for "Other (non-serious) Adverse Events" is listed as 0 because other (non-serious) Adverse Events were not collected/assessed.	1.8% 2/114 • Adverse event data was collected throughout the duration of the study. The mean follow-up for the participants who were not revised and did not pass away within 9 years of their hip replacement was 10 years. Serious adverse events were collected by questioning study participants and reviewing medical records. The denominator for "Other (non-serious) Adverse Events" is listed as 0 because other (non-serious) Adverse Events were not collected/assessed.
Musculoskeletal and connective tissue disorders Revision due to Wear/Osteolysis	0.00% 0/116 • Adverse event data was collected throughout the duration of the study. The mean follow-up for the participants who were not revised and did not pass away within 9 years of their hip replacement was 10 years. Serious adverse events were collected by questioning study participants and reviewing medical records. The denominator for "Other (non-serious) Adverse Events" is listed as 0 because other (non-serious) Adverse Events were not collected/assessed.	7.9% 9/114 • Adverse event data was collected throughout the duration of the study. The mean follow-up for the participants who were not revised and did not pass away within 9 years of their hip replacement was 10 years. Serious adverse events were collected by questioning study participants and reviewing medical records. The denominator for "Other (non-serious) Adverse Events" is listed as 0 because other (non-serious) Adverse Events were not collected/assessed.

Other adverse events

Adverse event data not reported

Additional Information

C. Anderson Engh, Jr., MD

AORI

Phone: 703-619-4411

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee The sponsor requires at least 30 days to review and comment on manuscripts before submission. For abstracts, the time frame for review is at least 10 days before submission. The sponsor will inform the investigator of any changes deemed necessary to preserve the confidentiality of proprietary information or to ensure scientific accuracy.
Publication restrictions are in place

Restriction type: OTHER