Importance of Hollow or Solid Centralizer for Polished, Collarless and Tapered Stems in Total Hip Arthroplasty

Study Overview
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Brief Summary
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The study aims at comparing the effect of hollow or solid centralizer designs on the long time fixation behaviour of hip prosthesis stems that are polished, tapered and collarless. In a prospective, controlled and randomized study comprising two groups of 30 patients/hips each, the patients will be followed up by RadioStereometric Analysis (RSA) for ten years. In completion general health questionnaires as well as hip specific scoring instruments will be used to evaluate patient satisfaction and outcome.The hypothesis of the study is that the different centralizers will result in different migration patterns of the stems, which might affect the risk for late aseptic loosening.

Official Title
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Comparing Hollow and Solid Centralizer Designs When Using a Polished, Collarless, Tapered Hip Prosthesis Stem (MS30). A Prospective, Randomized, Multicenter Study Evaluated by RadioStereometric Analysis (RSA).

Conditions
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Total Hip Arthroplasty

Intervention / Treatment
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* Procedure: Hollow Centralizer
* Procedure: Solid Centralizer
* Device: MS-30 femoral stem


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Primary osteoarthritis of the hip necessitating primary hip replacement Charnley classification group A and B Age 60 - 85 years old at the inclusion time of the study. Exclusion Criteria: Secondary osteoarthritis Rheumatoid arthritis Malignant disease Severe osteoporosis Earlier fracture or operation in the hip to be operated on Peroperative fracture Ongoing corticosteroid (oral) or immunosuppressive medication Personal disorders (dementia, alcohol or drug abuse etc) suspected of making completion of the trial uncertain.

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 85 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Hollow Centralizer<br>The stem used (MS30)was originally designed with a solid centralizer but has been redesigned to be used with a hollow centralizer. | Procedure: Hollow Centralizer<br>* The stem used (MS30)was originally designed with a solid centralizer but has been redesigned to be used with a hollow centralizer. The patients are randomized to either solid or hollow centralizer<br>Device: MS-30 femoral stem<br>* This is the stem used in the study.<br>|
| Active Comparator: Solid Centralizer<br>The stem used (MS30)was originally designed with a solid centralizer but has been redesigned to be used with a hollow centralizer. | Procedure: Solid Centralizer<br>* The stem used (MS30)was originally designed with a solid centralizer but has been redesigned to be used with a hollow centralizer. The patients are randomized to either solid or hollow centralizer<br>Device: MS-30 femoral stem<br>* This is the stem used in the study.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Radiostereometric Analysis (RSA) | This will measure the change in stem migration over time and be indicative of long term result. | The first postoperative day, 6 months, 1, 2, 5 and 10 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| x-ray | On standard x-rays the progress of radiolucent lines or other signs of loosening will be measured | The first postoperative day, 6 months, 1, 2, 5 and 10 years | 
| Hip specific questionnaire | Hip disability and Osteoarthritis Score (HOOS) - this is a hip specific questionnaire that will measure how the operation has affected the patients hip function and pain situation | Preoperatively, 1, 2, 5 and 10 years | 
| General health questionnaire | EuroQol (EQ-5D) - a standardized instrument for use as measure of general health outcome | Preoperatively, 1, 2, 5 and 10 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Radiostereometry, Total Hip Arthroplasty, Stem design