Efficacy of a New Resurfacing Hip Prosthesis

Study Overview
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Brief Summary
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The purpose of this study is to compare the articular surface replacement (ASR) prosthesis placed by the conventional positioning method and the ASR prosthesis placed by 'computer assisted surgery' (CAS) in variation between pre planned position of the femoral component and the actual position of the femoral component of the prosthesis. The hypothesis is that this variation is larger with the conventional positioning method than when CAS is used.

Detailed Description
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For patients who suffer from end stage of osteoarthritis of the hip, a joint replacement could result in an obvious improvement of the quality of life. However, because of the life expectation and high level of activity of young and active patients, the conventional total hip replacement does not offer an optimal solution. An alternative to a total hip replacement in young and active patients is the resurfacing hip prostheses. The articular surface replacement (ASR) hip prostheses can be placed by the conventional positioning method and by using 'computer assisted surgery' (CAS). The hypothesis is that the positioning of the femoral component by the conventional positioning method will show a larger variation between pre planned and actual position than when CAS is used. This study will compare the results of those who had an ASR prosthesis placed by the conventional positioning method with those patients in whom the ASR prosthesis was placed using CAS.

Official Title
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Efficacy of a New Resurfacing Hip Prosthesis. A Multicenter, Prospective, Randomized, Controlled Study

Conditions
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Osteoarthritis, Hip

Intervention / Treatment
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* Device: Articular Surface Replacement (ASR) hip prosthesis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men aged ≤ 60 years, and women aged ≤ 55 years Presence of evident clinical and radiological osteoarthritis of the hip, indicated for a joint replacement surgery Exclusion Criteria: Evident osteoporosis Active local or systemic infection Clinical manifestation of vascular deficiency of the lower extremity Pathological condition of the acetabulum Presence of evident clinical and radiological avascular necrosis of the femoral head, hip dysplasia, slipped capital femoral epiphysis, Legg-Calve- Perthes disease Rheumatoid arthritis Extreme varus position (neck-shaft angle < 110º) Presence of femoral cyst > 1 cm in diameter Previous hip surgery Presence of bilateral hip pathology, which may lead to joint replacement surgery within 1 year Presence of a THR at the contra lateral site less than 6 months post- operatively or patients with a THR at the contra lateral site with a poor function of the hip BMI> 30 kg/m2 Renal deficiency (creatine > 115 μmol/l for men and > 90 μmol/l for women) Medically proven metal allergy Request of patient to correct an existing leg length discrepancy Head-neck ratio < 1 Use of steroids, and/or immunosuppressive medication Alcoholism Patients from which it is not sure that they will be able to attend the follow-up measurements Insufficient command of the Dutch language, spoken and/of written

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>ASR prosthesis placed using CAS | Device: Articular Surface Replacement (ASR) hip prosthesis<br>* a DePuy ASR™ primary resurfacing femoral and acetabular component (DePuy International Ltd, Leeds, UK). The cement that will be used is one dose of DePuy SmartSet® GHV 40 gram, a high-viscosity cement with gentamycin (DePuy CMW, Blackpool, UK). Instrumentation includes standard ASR™ instruments and Ci™ Software for DePuy ASR™ System1.0.<br>|
| Active Comparator: 2<br>ASR prosthesis placed by conventional method | Device: Articular Surface Replacement (ASR) hip prosthesis<br>* a DePuy ASR™ primary resurfacing femoral and acetabular component (DePuy International Ltd, Leeds, UK). The cement that will be used is one dose of DePuy SmartSet® GHV 40 gram, a high-viscosity cement with gentamycin (DePuy CMW, Blackpool, UK). Instrumentation includes standard ASR™ instruments and Ci™ Software for DePuy ASR™ System1.0.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pre planned position of the femoral component preoperatively (stem-shaft-angle) |  | within 8 weeks before surgery | 
| actual position of the femoral component postoperatively (stem-shaft-angle) |  | within one week after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Harris Hip Score |  | preoperatively and at 6 weeks, 3, 12, 24 and 36 months postoperatively | 
| Hip pain |  | preoperatively and at 6 weeks, 3, 12, 24 and 36 months postoperatively | 
| Assessments of the position of femoral component (biomechanical parameters) at the X-rays |  | preoperatively, during the clinical phase and at 6 weeks, 3, 12, 24 and 36 months postoperatively | 
| Physical Activity Scale for Individuals with Physical Disabilities (PASIPD) |  | preoperatively and at 6 weeks, 3, 12, 24 and 36 months postoperatively | 
| Percentage of dynamic and static activities measured by the Rotterdam Activity Monitor (RAM) |  | preoperatively and at 3 and 6 months postoperatively | 
| Quality of life |  | preoperatively and at 6 weeks, 3, 12, 24 and 36 months postoperatively | 
| Early complications |  | within 3 months after surgery | 
| Later complications |  | longer than 3 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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resurfacing hip [MESH], conventional position method, surgery, computer-assisted [MESH]