Trial document





This trial has been registered retrospectively.
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  DRKS00000526

Trial Description

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Title

A study to evaluate the impact of implant position on the individual biomechanics and long-term results of not modular hip prostheses.

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Trial Acronym

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URL of the Trial

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Brief Summary in Lay Language

The hip joint has a complex biomechanics, which engages after hip arthroplasty in a variety of these parameters.
The orientation of the femoral and the acetabular components in the bone and the forces acting on the implant itself. Many studies have tried to examine the conditions that lead to increased wear and premature lossening. It has been shown the use of a navigation system to the hands-implantation to improve the implant position. To reduce the number of outliers and improve component orientation, various navigation systems (CAOS) have been developed for implanting total hip arthroplasties.
Earlier studies shows an improvement in implant position by using a navigation system compared to the free-hand implantation. However, the accuracy of some navigation systems by the body is affected mass index. An ultrasound-based navigation system will thereby require a higher accuracy. Hence, the purpose of this study was to compare an two different navigation systems in the postoperative acetabular cup position.
Patients with a hip osteoarthrosis will be included in this study.
The hypothesis of this study is that the use of ultrasound-based navigation system improves the accuracy of hip arthroplasty position.

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Brief Summary in Scientific Language

A malpositioning of the acetabular component during total hip arthroplasty increases the risk of dislocation, reduces the range of motion free of impingement and could lead to increased polyethylene wear. Hence, the cup orientation could affect the long-term outcome of the endoprosthesis.
Lewinnek et al., made recommendations for a safe zone of cup orientation to avoid dislocation by respecting an abduction of 40° (± 10°) and an anteversion of 15° (± 10°).
These recommendations for the target cup position are based on the percutaneously palpated osseous landmarks through the overlying soft tissue. These landmarks include the two anterosuperior iliac spines (ASISs) and the pubic symphysis, which collectively define the anterior pelvic plane (APP).
However, it has become evident that in numerous cases, this safe zone were not achieved even when an experienced surgeon performed the implantation using the freehand technique. The freehand technique has a broad range of cup orientation and postoperative radiographic examination shows many outliers from the safe zone. Initially, pre-operative computed tomography (CT) images were needed for CAOS, but since then, navigation systems independent of pre-operative imaging known as imageless navigation systems have gained increased acceptance. In their meta-analysis, Gandhi et al. showed that by using CAOS, outliers are reduced and there is a highly significant improvement in cup orientation compared to freehand positioning.
However, imageless navigation system with surface registration (imageless CAOS) are dependent on APP landmarks, which must be registered manually during the operation and which are then used as a frame of reference for positioning the cup.However, Parratte and Argenson discovered that the error of the cup positioning by an imageless CAOS is a function of the body-mass index (BMI). It is assumed that this poor correlation is induced through errors in registering the osseous landmarks of the symphysis as a result of the thickness of the suprapubic soft tissue Ultrasound-based navigation (US-based CAOS) appears to provide a better means of visualising the osseous landmarks, and even in vitro trials have shown a significant improvement of error in registering the anterior pelvic plane. However, the potential advantages of the ultrasound technique over imageless CAOS have not been evaluated in a clinical study setting to date.

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Organizational Data

  •   DRKS00000526
  •   2010/08/27
  •   [---]*
  •   yes
  •   Approved
  •   EA1/102/09, Ethik-Kommission der Charité -Universitätsmedizin Berlin-
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Secondary IDs

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Health Condition or Problem studied

  •   M16.0 -  Primary coxarthrosis, bilateral
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Interventions/Observational Groups

  •   Patients who have received a free-handed hip arthroplasies, get postoperativly a computed tomography (pelvis, knee and foot 6.3 mSv).
  •   Patients who have received a ultrasound-based navigated hip arthroplasty, get postoperativly a computed tomography (pelvis, knee and foot 6.3 mSv).
  •   Patients who have received a imageless navigated hip arthroplasty, get postoperativly a computed tomography (pelvis, knee and foot 6.3 mSv).
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Characteristics

  •   Interventional
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  •   Randomized controlled trial
  •   Single blind
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  •   Active control
  •   Treatment
  •   Parallel
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Primary Outcome

The postoperative implant position will evaluate using the 3D computed tomography (Somatom Sensation 64, Siemens Healthcare Sector, Forchheim, Germany). The accuracy of the navigation system will be measure between that what intraoperativly displayed by the navigation system postoperatively evaluate in the 3D computed tomography. A significant inaccuracy is postulated by a difference of more than 5 °.

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Secondary Outcome

The influence of the BMI and the soft tissue overlying the APP on the accuracy of navigation systems will be tested by using a statistical correlation.
In the absence of a significant correlation assumes a lack of influence.

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Countries of Recruitment

  •   Germany
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Locations of Recruitment

  • [---]*
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Recruitment

  •   Actual
  •   2010/05/19
  •   206
  •   Monocenter trial
  •   National
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Inclusion Criteria

  •   Both, male and female
  •   50   Years
  •   100   Years
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Additional Inclusion Criteria

1st Consent of patients.
2nd Patients aged 50 years
3rd Patients with osteoarthritis

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Exclusion Criteria

1st Patients who do not agree to participate in the study.
2nd Patients, aged <50 years.
3rd Patients, the footrests are in a dispute-the illness.
4th Patients who are incapacitated or limited legal capacity.

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Addresses

  • start of 1:1-Block address primary-sponsor
    • Klinik für Orthopädie, CMSC Berlin
    • Mr.  Prof.   Carsten   Perka 
    • Chariteplatz 1
    • 10117  Berlin
    • Germany
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    • Klinik für Orthopädie, CMSC Berlin
    • Mr.  Dr. med.   Georgi  Wassilew 
    • Charitreplatz 1
    • 10117  Belrin
    • Germany
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    • Klinik für Orthopädie, CMSC Berlin
    • Mr.  Dr. med.   Georgi  Wassilew 
    • Charitreplatz 1
    • 10117  Belrin
    • Germany
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Sources of Monetary or Material Support

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    • Klinik für Orthopädie, CMSC Berlin
    • Mr.  Prof.   Carsten   Perka 
    • Chariteplatz 1
    • 10117  Berlin
    • Germany
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Status

  •   Recruiting ongoing
  •   [---]*
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Trial Publications, Results and other Documents

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* This entry means the parameter is not applicable or has not been set.