Periprosthetic Bone Remodeling Around Uncemented Components in Total Hip Arthroplasty

Study Overview
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Brief Summary
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This is a randomized clinical trial comparing two different uncemented femoral stems and two different uncemented sockets using Dual-energy x-ray absorptiometry, Radiostereometry and clinical evaluation. Hypothesis: A short uncemented stem gives less periprosthetic bone resorption in the proximal femur than a conventional uncemented stem. An uncemented acetabular component with a backside of three-dimensional Titanium porous construct gives less periprosthetic bone resorption than a backside covered with a conventional porous coating with Titanium-beads and a hydroxy-apatite layer.

Detailed Description
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Consecutive patients 40-70 years old who are being planned for Total Hip Arthroplasty (THA) will be eligible for inclusion in the study. Periprosthetic bone remodeling, migration of the components and clinical scores will be recorded prospectively.

Official Title
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Periprosthetic Bone Remodeling Around Two Different Types of Uncemented Femoral Stems and Two Uncemented Acetabular Components in Total Hip Arthroplasty

Conditions
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Osteoarthritis

Intervention / Treatment
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* Procedure: Hip replacement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 40-70 years old Primary osteoarthritis of the hip Type A or B femur according to Dorr10 Femoral anatomy allowing implantation of both femoral stems Willingness and ability to follow study-protocol - Exclusion Criteria: Inflammatory arthritis Abnormal femoral anatomy after hip dysplasia, not suitable for implantation of components Treatment with bisphosphonates, cortisol or cytostatic drugs 6 months prior to surgery Ongoing oestrogen treatment Type C femur according to Dorr Not suited for the study for other reason (surgeons preference)

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 70 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
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Hip Arthroplasty, ultra-short stem, conventional cup<br>Hip replacement with a hydroxy-apatite covered ultra-short uncemented femoral stem and a conventional uncemented acetabular cup with hydroxy-apatite covered porous coating and a moderately cross-linked polyethylene cup liner | Procedure: Hip replacement<br>* Hip arthroplasty with uncemented components<br>* Other names: Tapered, proximally porous and hydroxyapatite-coated, Bimetric stem and a Regenerex cup with trabecular-Titanium-backside from Biomet.;|
| Experimental: Hip Arthroplasty, conventional stem, trabecular-titanium cup<br>Hip replacement with an uncemented tapered femoral stem and an uncemented acetabular cup with trabecular-Titanium backside and E-vitamin-treated polyethylene cup liner | Procedure: Hip replacement<br>* Hip arthroplasty with uncemented components<br>* Other names: Tapered, proximally porous and hydroxyapatite-coated, Bimetric stem and a Regenerex cup with trabecular-Titanium-backside from Biomet.;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bone remodelling, i e change in bone mineral density around the stem, as measured with dual energy x-ray absorptiometry (DEXA) |  | bone mineral density (BMD) measured postoperatively at 2 years. | 
| Bone remodelling, i e change in bone mineral density behind the acetabular component, as measured with dual energy x-ray absorptiometry (DEXA) |  | bone mineral density (BMD) measured postoperatively at 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Migration of stem components in six degrees of freedom and maximum total point motion measured with radiostereometric analysis (RSA) |  | at 2 years | 
| Migration of acetabular components in six degrees of freedom and maximum total point motion of the head center measured with radiostereometric analysis (RSA) |  | at 2 years | 
| Migration of acetabular components in six degrees of freedom and maximum total point motion of the head center measured with radiostereometric analysis (RSA) |  | at 6 and 10 years | 
| Bone remodelling, i e change in bone mineral density around the stem and cup, as measured with dual energy x-ray absorptiometry (DEXA) |  | at 6 and 10 years. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Periprosthetic bone remodeling, Stress shielding, Short femoral stem, Porous Titanium Construct, Polyethylene wear