Influence of pelvic tilt on functional acetabular orientation.

Background: Pelvic tilt influences acetabular orientation (AO). Anatomical AO can be measured in relation to the anterior pelvic plane (APP), functional AO can be calculated relative to table's plane.

Objective: To assess to what extent functional AO is determined by pelvic tilt and if APP and table plane give equal information for correct AO.

Pelvic tilt compensates for increased acetabular anteversion.

Purpose: Pelvic tilt determines functional orientation of the acetabulum. In this study, we investigated the interaction of pelvic tilt and functional acetabular anteversion (AA) in supine position.

Methods: Pelvic tilt and AA of 138 individuals were measured by computed tomography (CT).

The sagittal stem alignment and the stem version clearly influence the impingement-free range of motion in total hip arthroplasty: a computer model-based analysis.

Purpose: The component alignment in total hip arthroplasty influences the impingement-free range of motion (ROM). While substantiated data is available for the cup positioning, little is known about the stem alignment. Especially stem rotation and the sagittal alignment influence the position of the cone in relation to the edge of the socket and thus the impingement-free functioning.

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.

Femoral Offset (3D) in Patients without Osteoarthritis - Index Values from 200 Hip Joints.

Introduction: Femoral offset (FO) is a crucial parameter for hip joint biomechanics. Reference values for FO are particularly important when joint geometry has to be reconstructed during surgical interventions. Such reference values are scarce in literature and have mainly been obtained from osteoarthritis (OA) patients.

Real time visualization of femoroacetabular impingement and subluxation using 320-slice computed tomography.

We visualized extreme ranges of motion of the hip and located femoroacetabular impingement (FAI) and subluxations using 4dimensional (D) volume computed tomography (CT). In dynamic 4D CT, 30 patients with hip pain (>3 months) and positive clinical and radiological signs of impingement were prospectively analyzed. The investigations were performed in flexion, abduction, and external rotation.

The direct lateral approach: impact on gait patterns, foot progression angle and pain in comparison with a minimally invasive anterolateral approach.

Introduction: Minimally invasive total hip arthroplasty has been successfully introduced in the past decade. Nevertheless, standard approaches such as the direct lateral approach are still commonly used in orthopaedic surgery due to easy handling, good intra-operative overview and low complication rates. However, a frequent occurrence of fatty atrophy within the anterior third of the gluteus medius muscle has been demonstrated when using the modified direct-lateral approach (mDL), which may be associated with a reduction in function, limitation of internal leg rotation, gait disorders and pain.

The sex specificity of hip-joint muscles offers an explanation for better results in men after total hip arthroplasty.

Purpose: Choosing a surgical approach for total hip arthroplasty (THA) has a patient-specific impact on peri-operative muscle damage as well as postoperative functional outcome. Women and aged patients increasingly benefit from minimally invasive surgical procedures. For this reason, and due to the distinctly different bony anatomy of men and women, the hypothesis of this study is that muscle distribution around the hip joint is dependent on sex and age.

A formula to predict patients' gluteus medius muscle volume from hip joint geometry.

The volume of the gluteus medius muscle (GMV) has been shown to be closely related to hip joint function. A defined relation between joint geometry and GMV would allow a calculation of the patient-specific GMV providing reference values to individually determine the goals for rehabilitation programs after total hip arthroplasty (THA). The aim of this study was to investigate correlations between hip geometry and GMV.

Time course of skeletal muscle regeneration after severe trauma.

Background And Purpose: Animal models of skeletal muscle injury should be thoroughly described and should mimic the clinical situation. We established a model of a critical size crush injury of the soleus muscle in rats. The aim was to describe the time course of skeletal muscle regeneration using mechanical, histological, and magnetic resonance (MR) tomographic methods.

Age-related appearance of muscle trauma in primary total hip arthroplasty and the benefit of a minimally invasive approach for patients older than 70 years.

Old age is frequently associated with a poorer functional outcome after THA. This might be based upon muscular damage resulting from surgical trauma. Minimally invasive approaches have been widely promoted on the basis of the muscle sparing effect.

Dynamic stabilization adjacent to single-level fusion: part I. Biomechanical effects on lumbar spinal motion.

Progression of superior adjacent segment degeneration (PASD) could possibly be avoided by dynamic stabilization of an initially degenerated adjacent segment (AS). The current study evaluates ex vivo the biomechanics of a circumferential fixation connected to posterior dynamic stabilization at the AS. 6 human cadaver spines (L2-S1) were stabilized stepwise through the following conditions for comparison: intact spine (ISP), single-level fixation L5-S1 (SLF), SLF + dynamic AS fixation L4-L5 (DFT), and two-level fixation L4-S1 (TLF).

[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.

Relationship between cup position and obturator externus muscle in total hip arthroplasty.

Background: It is often challenging to find the causes for postoperative pain syndromes after total hip replacement, since they can be very allotropic. One possible cause is the muscular impingement syndrome. The most commonly known impingement syndrome is the psoas impingement.

Dynamic stabilization adjacent to single-level fusion: part II. No clinical benefit for asymptomatic, initially degenerated adjacent segments after 6 years follow-up.

Progression of degeneration is often described in patients with initially degenerated segment adjacent to fusion (iASD) at the time of surgery. The aim of the present study was to compare dynamic fixation of a clinically asymptomatic iASD, with circumferential lumbar fusion alone. 60 patients with symptomatic degeneration of L5/S1 or L4/L5 (Modic ≥ 2°) and asymptomatic iASD (Modic = 1°, confirmed by discography) were divided into two groups.

The association between the sagittal femoral stem alignment and the resulting femoral head centre in total hip arthroplasty.

Adequate stem alignment is essential for the success of Total Hip Arthroplasty (THA) to avoid dislocation and impingement. One factor that has not been sufficiently investigated so far is the stem tilting in the sagittal plane, which has an influence on the position of the centre of the femoral head and thus also on prosthesis torsion. We aimed to evaluate sagittal stem position using 3D-CTs in patients with THA and to develop a mathematical-geometrical model to simulate the functional correlation between sagittal stem tilting and the influence on functional anteversion.

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.

Randomized controlled trial of abductor muscle damage in relation to the surgical approach for primary total hip replacement: minimally invasive anterolateral versus modified direct lateral approach.

Introduction: Minimally invasive total hip arthroplasty (THA) is claimed to be superior to the standard technique, due to the potential reduction of soft tissue damage via a smaller and tissue-sparing approach. As a result of the lack of objective evidence of fewer muscle and tendon defects, controversy still remains as to whether minimally invasive total hip arthroplasty truly minimizes muscle and tendon damage. Therefore, the objective was to compare the influence of the surgical approach on abductor muscle trauma and to analyze the relevance to postoperative pain and functional recovery.

Evidence of reduced muscle trauma through a minimally invasive anterolateral approach by means of MRI.

Background: Minimally invasive techniques in THA are intended to minimize periarticular muscle trauma. The lateral approach has a risk of partial gluteal insufficiency, while the anterolateral approach carries the risk of damaging the tensor fasciae latae through intermuscular nerve and compression injury.

Questions/purposes: We assessed the surgical influence of the anterolateral minimally invasive approach and the modified direct lateral approach on the tensor fasciae latae and gluteus medius.

MRI findings of gluteus minimus muscle damage in primary total hip arthroplasty and the influence on clinical outcome.

Introduction: The influence of surgical trauma on gluteus minimus muscle in total hip arthroplasty (THA) and the impact on functional outcome has been hardly investigated up to now. Potential risks of minimus damage during the approach or femoral preparation is due to its attachment to the anterior facet of the greater trochanter. Possible trauma-associated functional deficits of minimus muscle may result in reduced abduction force or in an unstable hip joint.

Inter- and intraobserver variability in the postoperative evaluation of transpedicular stabilization: computed tomography versus magnetic resonance imaging.

Background Context: Computed tomography (CT) represents the state of the art for the postoperative verification of the implant position after transpedicular stabilizations. Magnetic resonance imaging (MRI) has not challenged the CT, yet, because of susceptibility artifacts but would be favorable as a diagnostic tool for its excellent soft-tissue qualities.

Purpose: A study that analyzed if an artifact-reduced MRI could overcome this problem and provide sufficient data for the postoperative assessment was conducted.

Periprosthetic femoral fractures: outcome after treatment with LISS internal fixation or stem replacement in 36 patients.

Periprosthetic fractures of the femur present a challenging surgical problem. The aim of this study was to evaluate the outcome of periprosthetic femoral fractures (PFF) which were treated with internal fixation or stem revision. Depending on the fracture type in the Duncan-Vancouver-Classification, 42 patients with PFF were treated either with a Fixateur interne (n = 23) in cases with type B1 or C fractures, or with stem revision (n = 19) in cases with type B2/B3 fractures.

Validity of frozen sections for analysis of periprosthetic loosening membranes.

Unlabelled: Clinical findings and blood parameters often are inconclusive in patients with periprosthetic joint infections. Among the accepted criteria for diagnosis, histologic analysis of debrided tissue can detect infection in most cases but does not allow intraoperative decision making. We evaluated the validity of intraoperative frozen sections for detection of prosthetic infections.