A Prospective Randomized Controlled Trial of Dual-Mobility Components in Primary THA

Study Overview
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Brief Summary
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The aim of this study is to determine if the use of a modular dual mobility bearing is associated with clinically important increases in serum metal levels.

Detailed Description
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Prosthetic dislocation following total hip arthroplasty (THA) remains a significant concern with a reported incidence of 0.2%-7.0% after primary and 10%-25% after revision THA. The risk of dislocation following THA is multifactorial and includes both surgeon-related factors (i.e. component positioning, surgical approach) and patient-related factors (i.e. gender, age). Dual mobility articulations have been shown to reduce the incidence of hip instability following THA. Dual mobility implants have been used in Europe for over 30 years, but have recently received an increased interest in the United States. Initial dual mobility designs consisted of a cementless, monoblock acetabular component with a highly-polished metal inner bearing surface. Modular dual mobility prostheses have been introduced in which a modular cobalt-alloy liner is inserted into a hemispherical titanium acetabular component. Advantages of this construct include familiarity of use of a standard titanium acetabular component and the ability to use supplemental screw fixation. However, the potential for fretting corrosion between the cobalt-alloy liner and the titanium acetabular component remains a concern. In a retrospective review of 100 consecutive patients undergoing primary THA using a modular dual mobility prosthesis, the authors found 21% of patients to have a serum cobalt level above the normal range, with 9% significantly above normal (> 1.6 ug/L), at a mean of 27.6 months postoperatively. In addition, a recent prospective cohort study of 26 patients receiving the same prosthesis showed elevated whole blood mean cobalt levels in patients receiving a modular dual mobility prosthesis versus patients receiving a conventional bearing (0.23 + 0.39 vs. 0.15 + 0.07ug/L, p<0.001) at 1 year postoperatively. Four patients in the dual mobility cohort had a whole blood cobalt level outside the reference range (maximum 1.81 ug/L). To the investigators knowledge no prospective, randomized controlled trial has been performed comparing dual mobility bearings to a conventional single-bearing design. Therefore, the purpose of this study is to compare the use of a conventional single-bearing ceramic-on-polyethylene surface to use of a modular dual mobility bearing in a prospective, randomized controlled setting.

Official Title
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A Prospective Randomized Trial of Modular Dual Mobility Acetabular Components Versus Conventional Single Bearing Components in Primary Total Hip Arthroplasty

Conditions
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Serum Metal Levels, Specifically Cobalt, Chromium, and Titanium

Intervention / Treatment
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* Device: Dual mobility cohort
* Device: Conventional cohort


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18 and 80 years Willingness to undergo serial postoperative venipuncture for serum meal analysis BMI < 40 Patients that are eligible for the requisite implants as deemed by their surgeon Exclusion Criteria: Clinically significant systemic chronic disease Diminished renal function Presence of any metal-containing implant outside of the oral cavity History of prior hip surgery involving an internal fixation device History of hip infection Preoperative diagnosis other than osteoarthritis Anticipated need for another joint replacement surgery within one year Patients taking chromium supplements

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Patients will be randomized to 1 of 2 treatment groups, which they will be in for the duration of the study. Because of the nature of the study, there will be no crossover.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Conventional Cohort<br>Patients in this group will receive a Taperloc femoral stem, ceramic femoral head (size 32mm for acetabular components 48/50mm; size 36mm for acetabular components > 52mm), polyethylene bearing, and G7 acetabular shell. | Device: Conventional cohort<br>* Patients will receive a Taperloc femoral stem, ceramic femoral head (size 32mm for acetabular components 48/50mm; size 36mm for acetabular components > 52mm), polyethylene bearing, and G7 acetabular shell<br>|
| Experimental: Modular Dual Mobility Cohort<br>Patients in this group will receive a Taperloc femoral stem, inner ceramic femoral head (28mm), mobile polyethylene bearing, cobalt alloy liner, and G7 acetabular shell. | Device: Dual mobility cohort<br>* Patients will receive the Taperloc femoral stem, ceramic femoral head (size 32mm for acetabular components 48/50mm; size 36mm for acetabular components > 52mm), polyethylene bearing, and G7 acetabular shell.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum chromium levels, measures chromium level in the serum in ug/L | Assays for each subject for serum chromium in ug/L | up to 5 years | 
| Serum cobalt levels, measures cobalt level in the serum in ug/L | Assays for each subject for serum cobalt in ug/L | up to 5 years | 
| Serum titanium levels, measures titanium level in the serum in ug/L | Assays for each subject for serum titanium in ug/L | up to 5 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient reported outcome measures (survey) for SF-12 score. | Subjects will complete the industry common SF-12 survey and total score will be used. Higher scores are better, score of 100 is maximum. | up to 5 years | 
| Patient reported outcome measures (survey) for the Harris Hip Score | Subjects will complete the industry common Harris Hip survey and total score will be used. Higher scores are better, score of 100 is maximum. | up to 5 years | 
| Patient reported outcome measures (survey) for the Hoos Jr. score. | Subjects will complete the industry common HOOS Jr. survey and total score will be used. Higher scores are better, score of 100 is maximum. | up to 5 years | 
| Patient reported outcome measures (survey) for the SANE score. | Subjects will complete the the industry common SANE survey and total score will be used. Higher scores are better, score of 100 is maximum. | up to 5 years | 
| Patient reported outcome measures (survey) for the UCLA activity score. | Subjects will complete the the industry common UCLA survey and total score will be used. Higher scores are better, score of 100 is maximum. | up to 5 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dual Mobility, Serum metal levels