knee kinematics of an innovative prosthesis design.

Up to 20% of patients after total knee arthroplasty (TKA) are not satisfied with the result. Several designs of new implants try to rebuild natural knee kinematics. We hypothesized that an innovative implant design leads to better results concerning femoral rollback compared to an established implant design.

Visual intraoperative estimation of range of motion is misleading in minimally invasive total hip arthroplasty.

Introduction: Generally range of motion (ROM) in total hip arthroplasty (THA) is intraoperatively assessed by eye. Can we assume that visual estimation of ROM is reliable?

Methods: 60 patients underwent cementless THA in a subgroup analysis of a clinical prospective trial using a minimally invasive anterolateral approach in lateral decubitus position. Four experienced surgeons intraoperatively estimated ROM visually by assessment of the femur relative to the alignment of the patient's pelvis.

Soft tissue restricts impingement-free mobility in total hip arthroplasty.

Purpose: Impingement is a major source for decreased range of motion (ROM) and dislocation in total hip arthroplasty (THA). In the current study we analyzed the impact of soft tissue impingement on ROM compared to bony and/or prosthetic impingement.

Methods: In the course of a prospective clinical trial 54 patients underwent cementless total hip arthroplasty in the lateral decubitus position using imageless navigation.

Visual intraoperative estimation of cup and stem position is not reliable in minimally invasive hip arthroplasty.

Background and purpose - In hip arthroplasty, acetabular inclination and anteversion-and also femoral stem torsion-are generally assessed by eye intraoperatively. We assessed whether visual estimation of cup and stem position is reliable. Patients and methods - In the course of a subgroup analysis of a prospective clinical trial, 65 patients underwent cementless hip arthroplasty using a minimally invasive anterolateral approach in lateral decubitus position.

Radiographic Assessment of Femoral Stem Torsion in Total Hip Arthroplasty-A Comparison of a Caput-Collum-Diaphyseal Angle-Based Technique With the Budin View.

Background: Correct assessment of femoral stem torsion is crucial in total hip arthroplasty (THA). In this study, we aimed to compare a recently published novel method based on anteroposterior (AP) hip radiographs using the projected caput-collum-diaphyseal (CCD) angle (AP CCD) with the modified posteroanterior Budin view.

Method: AP radiographs, modified Budin views, and 3-dimensional computed tomography (3D-CT) images were obtained in 30 patients after minimally invasive, cementless THA.

Fluoroscopy and imageless navigation enable an equivalent reconstruction of leg length and global and femoral offset in THA.

Background: Restoration of biomechanics is a major goal in THA. Imageless navigation enables intraoperative control of leg length equalization and offset reconstruction. However, the effect of navigation compared with intraoperative fluoroscopy is unclear.

Improved kinematics of total knee replacement following partially navigated modified gap-balancing technique.

Purpose: Navigation-based total knee arthroplasty (TKA) has proven its value for restoration of the limb axis. However, patient-orientated results after TKA show a wide variation from the correct implantation technique. Nonphysiological kinematics without posterior femoral rollback and tibial internal rotation in flexion could be one reason for this.

Minimally invasive computer-navigated total hip arthroplasty, following the concept of femur first and combined anteversion: design of a blinded randomized controlled trial.

Background: Impingement can be a serious complication after total hip arthroplasty (THA), and is one of the major causes of postoperative pain, dislocation, aseptic loosening, and implant breakage. Minimally invasive THA and computer-navigated surgery were introduced several years ago. We have developed a novel, computer-assisted operation method for THA following the concept of "femur first"/"combined anteversion", which incorporates various aspects of performing a functional optimization of the cup position, and comprehensively addresses range of motion (ROM) as well as cup containment and alignment parameters.