Evaluation of sonicate fluid cultures in comparison to histological analysis of the periprosthetic membrane for the detection of periprosthetic joint infection.

Purpose: The aim of this prospective study was to evaluate the diagnostic efficacy of sonicate fluid cultures (SFC) and the histological analysis of the periprosthetic membrane (PM) for the detection of periprosthetic joint infection (PJI).

Methods: The histological samples were evaluated according to the consensus classification of PM as defined by Morawietz and Krenn. All explanted endoprosthesis were subject to sonication.

Ultrasound-based computer navigation of the acetabular component: a feasibility study.

Introduction: This feasibility study investigated the accuracy of anterior pelvic reference plane (APP) registration and acetabular cup orientation in two cadavers with different BMIs.

Method: Five observers each registered the APP five times in the 2 cadavers (BMIs: 32 kg/m(2) and 25 kg/m(2)) using an ultrasound-based navigation system. By comparison against the CT-derived reference landmarks, the errors in determining the individual landmarks defining the APP, as well as the resulting errors in the orientation of the APP and the acetabular cup orientation were determined.

Use of an ultrasound-based navigation system for an accurate acetabular positioning in total hip arthroplasty: a prospective, randomized, controlled study.

The purpose of this study was to compare an ultrasound-based navigation system with an imageless navigation system with surface registration in the postoperative acetabular cup position. A prospective randomized controlled study of 2 groups of 40 patients each was performed. In the first group, cup positioning was assisted by an ultrasound-based navigation system, and in the second group, the cup was assisted by imageless navigation system with surface registration.

Validation of a CT image based software for three-dimensional measurement of acetabular cup orientation.

The purpose of our study was to develop a simple and reproducible method for calculating post-operative acetabular cup position based upon computed tomographic images. Next, we sought to examine the reliability, objectivity and accuracy of this method. We developed a 3D CT evaluation software based upon Amira® (data visualisation, analysis and modelling software) to calculate the abduction and anteversion of the acetabular cup relative to the APP (anterior pelvic plane).

Influence of body mass index and thickness of soft tissue on accuracy of ultrasound and pointer based registration in navigation of cup in hip arthroplasty.

Background: Precise identification of bony landmarks by use of pointer based navigation systems is influenced by thickness of soft tissue. Ultrasound-based navigation systems try to overcome the problems of positional deviation associated with soft tissue. The aim of the study was to investigate the influence of the BMI and the thickness of the soft tissue on the post-operative cup position and accuracy in the application of an ultrasound-based (US CAOS) and a pointer-based navigation system (P CAOS).

3D CT analysis of combined cup and stem anteversion in cases of cup navigation in hip arthroplasty.

Navigation of the cup in total hip arthroplasty is well analyzed and shows accurate results, reducing cup outliers of Lewinnek's "safe zone." With regard to the combined anteversion of cup and stem, however, a "new" safe zone with a range of 25° to 50° has been published. The aim of this study was to analyze total anteversion (cup and stem) by postoperative 3D computed tomography in isolated cup navigation cases.

[Reconstruction of large acetabular defects using trabecular metal augments].

Objective: Revision of cup and reconstruction of original center of rotation. High primary and secondary stability. Prevention of additional bone loss.

CT evaluation of native acetabular orientation and localization: sex-specific data comparison on 336 hip joints.

Background: The reorientation of the acetabular component in total hip replacement is currently carried out under consideration of the safe zone, respecting the best possible range of motion and is influenced by wear debris of different bearings. Is the preferred orientation a reconstruction of the native anatomy and are there sex-specific differences?

Methods: On the basis of 168 CT datasets (72 women, 96 men) 336 native hip joints were analysed. The abduction and anteversion of the acetabulum as well as the location of the hip center were detected.

Ultrasound-based navigation and 3D CT compared in acetabular cup position.

Intraoperative landmarks are used in image-free navigation systems. The ultrasound-based navigation systems try to overcome the problems of positional deviation associated with soft tissue. Our study analyzed the accuracy of ultrasound-based navigation of cup positioning compared with postoperative 3-dimensional (3D) computed tomography scans of cup positioning.

Comparison between pointer-based and ultrasound-based navigation technique in THA using a minimally invasive approach.

The use of navigation techniques in primary total hip arthroplasty improves the position of endoprosthetic components, especially cup positioning. An intraoperative registration of the anterior pelvic plane is necessary to define the anteversion and inclination angles on the acetabular side. This study compares the accuracy of manual pointer palpation to ultrasound registration in navigation to determine pelvic plane registration in 60 cases of minimally invasive surgical technique.

Diagnosis of periprosthetic infection following total hip arthroplasty--evaluation of the diagnostic values of pre- and intraoperative parameters and the associated strategy to preoperatively select patients with a high probability of joint infection.

Background: The correct diagnosis of a prosthetic joint infection (PJI) is crucial for adequate surgical treatment. The detection may be a challenge since presentation and preoperative tests are not always obvious and precise. This prospective study was performed to evaluate a variety of pre- and intraoperative investigations.