Osteolysis Development Around Uncemented Cups With or Without Screw Holes

Study Overview
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Brief Summary
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In order to investigate the role of acetabular cup screw holes for the transport of osteolysis-inducing particles in a total hip arthroplasty articulation, the investigators compare the amount of bone loss around acetabular cups with and without holes. Bone loss is measured with computed tomography at 7 years and 15 - 18 years of follow-up.

Detailed Description
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Particles generated by wear and corrosion within an artificial hip articulation can cause biologically mediated bone loss in the surrounding pelvis. Particles can be found within immunologically active cells inside bone lesions. Holes intended for screw fixation in uncemented acetabular cups are believed to be a main route for these particles from the articulation into the pelvic bone. Using pressfit, screws are not always necessary for a successful fixation of an uncemented cup. The investigator's hypothesis is that a pressfit fixated cup without screw holes will display a decreased amount of periacetabular osteolysis compared to a cup with screw holes. Therefore, 95 hips (90 patients) were randomized to receive either pressfit cups without screw holes or the same type of cup with screw holes. The occurence and size of periacetabular osteolysis will be compared between the two groups. In addition, since the patients will have a computed tomography examination at 7 years and between 15 and 18 years the investigator will also analyze development of periacetabular osteolysis over time. The different cups were paired with three different types of femoral stems. Also, articulation wear and cup and stem fixation will be analyzed using radiostereometry.

Official Title
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Osteolysis Development Over Time Around Uncemented Titanium Fiber Mesh Cups With or Without Screw Holes

Conditions
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Arthroplasty Complications

Intervention / Treatment
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* Device: Uncemented acetabular cup with screw holes
* Device: Uncemented acetabular cup without screw holes


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: primary or secondary osteoarthritis Exclusion Criteria: Inflammatory osteoarthritis, hip joint infection

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 75 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 |
| --- | --- |
| Active Comparator: Cup with screw holes<br>Uncemented Trilogy cup (Zimmer, Warzaw, IN, US), screw fixation (2 or 3 screws) | Device: Uncemented acetabular cup with screw holes<br> <br> |
| Experimental: Cup without screw holes<br>Uncemented Trilogy cup (Zimmer, Warzaw, IN, US) without screw holes, press-fit fixation | Device: Uncemented acetabular cup without screw holes<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Periacetabular osteolysis frequency change between 7 and 18 years | Frequency of osteolysis (%) measured with computed tomography | Change between 7 to 18 years after surgery | 
| Periacetabular osteolysis size change between 7 and 18 years | Size of periacetabular osteolysis (cm3) masured with computed tomography | Change between 7 to 18 years after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cup fixation (translation) | Cup translation (mm/year) measured with radiostereometry, calculated from multiple measurements during the study period | 18 years postoperatively | 
| Cup fixation (rotation) | Cup rotation (degrees/year) measured with radiostereometry, calculated from multiple measurements during the study period | 18 years postoperatively | 
| Polyethylene wear | Polyethylene wear (mm/year) measured with radiostereometry, calculated from multiple measurements during the study period | 18 years postoperatively | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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uncemented hip arthroplasty, osteolysis, polyethylene wear, implant design