In Vitro Biocompatibility of the Novel Ceramic Composite Baghdadite for Defect Augmentation in Revision Total Hip Arthroplasty.

Biological augmentation of bony defects in weight-bearing areas of both the acetabulum and the femur remains challenging. The calcium-silicate-based ceramic Baghdadite is a very interesting material to be used in the field of revision total hip arthroplasty for the treatment of bony defects in weight-bearing and non-weight-bearing areas alike. The aim of this study was to investigate the biocompatibility of Baghdadite utilizing an osteoblast-like, human osteosarcoma cell line (MG-63) and the human monocytic leukemia-derived cell line (THP-1).

Vertebral Bone Marrow-Derived Mesenchymal Stromal Cells from Osteoporotic and Healthy Patients Possess Similar Differentiation Properties In Vitro.

Osteoporosis is a disease characterized by low bone mass and an increased risk of fractures. Although several cellular players leading to osteoporosis have been identified, the role of mesenchymal stromal cells (MSC) is still not fully elaborated. The aim of this study was, therefore, to isolate and characterize MSCs from vertebral body of healthy non-osteoporotic and osteoporotic patients, with a particular focus on their osteogenic differentiation potential.

High-Dimensional Analysis of Immune Cell Composition Predicts Periprosthetic Joint Infections and Dissects Its Pathophysiology.

Accurate diagnosis of periprosthetic joint infections (PJI) is one of the most widely researched areas in modern orthopedic endoprosthesis. However, our understanding of the immunological basis of this severe complication is still limited. In this study, we developed a flow cytometric approach to precisely characterize the immune cell composition in periprosthetic joints.

Molecular and Functional Phenotypes of Human Bone Marrow-Derived Mesenchymal Stromal Cells Depend on Harvesting Techniques.

Mesenchymal stromal cells (MSC) harvested in different tissues from the same donor exhibit different phenotypes. Each phenotype is not only characterized by a certain pattern of cell surface markers, but also different cellular functionalities. Only recently were different harvesting and processing techniques found to contribute to this phenomenon as well.

Characterization and Comparison of Human and Ovine Mesenchymal Stromal Cells from Three Corresponding Sources.

Currently, there is an increasing focus on mesenchymal stromal cells (MSC) as therapeutic option in bone pathologies as well as in general regenerative medicine. Although human MSCs have been extensively characterized and standardized, ovine MSCs are poorly understood. This limitation hampers clinical progress, as sheep are an excellent large animal model for orthopedic studies.

Osteoimmunology: A Current Update of the Interplay Between Bone and the Immune System.

Immunology, already a discipline in its own right, has become a major part of many different medical fields. However, its relationship to orthopedics and trauma surgery has unfortunately, and perhaps unjustly, been developing rather slowly. Discoveries in recent years have emphasized the immense breadth of communication and connection between both systems and, importantly, the highly promising therapeutic opportunities.

Extracellular Vesicle Isolation and Characterization from Periprosthetic Joint Synovial Fluid in Revision Total Joint Arthroplasty.

Extracellular vesicles (EVs) comprise an as yet insufficiently investigated intercellular communication pathway in the field of revision total joint arthroplasty (RTJA). This study examined whether periprosthetic joint synovial fluid contains EVs, developed a protocol for their isolation and characterized them with respect to quantity, size, surface markers as well as documented their differences between aseptic implant failure (AIF) and periprosthetic joint infection (PJI). EV isolation was accomplished using ultracentrifugation, electron microscopy (EM) and nanoparticle tracking analysis evaluated EV presence as well as particle size and quantity.

Gene expression analysis of vastus medialis cells after tourniquet-induced ischemia during total knee arthroplasty: a randomized clinical trial.

Purpose: Postoperative quadriceps muscle strength was lowered after tourniquet application during total knee arthroplasty (TKA). Furthermore, tourniquet application results in higher proteolytic activity within vastus medialis cells, without influence on the amount and function of mitochondria. The effects of the commonly utilized intraoperative tourniquet on gene expression within the human skeletal muscle cells are barely examined.

No effect of tourniquet in primary total knee arthroplasty on muscle strength, functional outcome, patient satisfaction and health status: a randomized clinical trial.

Purpose: Tourniquet use during primary total knee arthroplasty (TKA) may negatively impact the early postoperative functional recovery due to molecular effects of ischaemia. The hypothesis of the present study was that primary TKA without a tourniquet positively influences the postoperative muscle strength, functional outcome, patient satisfaction and health status.

Methods: The monocentric, randomized, controlled trial included a total of 99 patients scheduled to undergo primary TKA (ClinicalTrials.

Tourniquet application does not affect the periprosthetic bone cement penetration in total knee arthroplasty.

Purpose: Poor scientific evidence exists on the issue of tourniquet application during total knee arthroplasty (TKA). It has been suggested that tourniquet application might improve interdigitation of the cement into the periprosthetic bones due to relatively dry surgical field. The hypothesis of the present study was that tourniquet use did not affect the periprosthetic bone cement penetration.

Increased extracellular ubiquitin in surgical wound fluid provides a chemotactic signal for myeloid dendritic cells.

Purpose: Myeloid dendritic cells (MDC) decline significantly after multiple traumas which might be due to an increased migration into injured regions. Ubiquitin is released from dying cells and is increased in serum after trauma. Ubiquitin can bind to the chemokine receptor CXCR4.

Tourniquet application during TKA did not affect the accuracy of implant positioning: a randomized clinical trial.

Purpose: The accuracy of the identification of anatomical landmarks with versus without tourniquet application and its effect on implant positioning remained unknown. Therefore, the hypothesis of the present study was that tourniquet application did not affect the accuracy of the reconstruction of the mechanical leg alignment, the joint line level, and the patellar height.

Methods: The prospective randomized monocentric trial (Clinical-Trials.

Outcome in total knee arthroplasty with a medial-lateral balanced versus unbalanced gap.

Purpose: To evaluate the clinical outcome in 108 total knee arthroplasty (TKA) patients with a medial-lateral balanced versus unbalanced gap after a mean follow-up of 34 months.

Methods: 64 women and 44 men (mean age, 69.5 years) underwent computer-assisted TKA for osteoarthritis using a cemented fixed-bearing cruciate-retaining prosthesis.

Effect of limited ischemia time on the amount and function of mitochondria within human skeletal muscle cells.

Introduction: The clinical success of total knee arthroplasty (TKA) depends substantially on the quadriceps muscle function. A frequently applied thigh tourniquet during TKA may induce ischemia related injuries to quadriceps muscle cells. Animal limb muscles subjected to 2-5 h ischemia revealed dysfunctional mitochondria, which in turn compromised the cellular bioenergetics and increased the level of reactive oxygen species.

Tourniquet-induced ischaemia during total knee arthroplasty results in higher proteolytic activities within vastus medialis cells: a randomized clinical trial.

Purpose: Recent data suggest diminished post-operative quadriceps muscle strength after tourniquet application during total knee arthroplasty (TKA). The metabolic effects of the commonly utilized intraoperative tourniquet with consecutive ischaemia on the skeletal muscle cells were unknown. Ubiquitin proteasome system represents one of the main pathways involved in muscle protein breakdown contributing to muscle atrophy.

Preservation of the PCL when performing cruciate-retaining TKA: Is the tibial tuberosity a reliable predictor of the PCL footprint location?

Purpose: Reconstruction of the joint line is crucial in total knee arthroplasty (TKA). A routine height of tibial cut to maintain the natural joint line may compromise the preservation of the PCL. Since the PCL footprint is not accessible prior to tibial osteotomy, it seems beneficial to identify a reliable extraarticular anatomic landmark for predicting the PCL footprint and being visible within standard TKA approach.

Are joint line changes after primary navigated total knee arthroplasty predictable?

Background: Navigation systems have been successful in reducing the outlier of leg alignment after total knee arthroplasty (TKA). Less is known about the restoration of the anatomical joint line with computer-assisted knee replacement. The aim of this study was to determine whether joint line changes <3 or ≥3 mm are predictable with several pre- and intraoperative parameters.

Alteration of the patellar height following total knee arthroplasty.

Introduction: Patellofemoral related complications after total knee arthroplasty (TKA) remain clinically relevant. The hypothesis of the present study was that the patellar height changes more than 10% of its preoperative height after TKA. Possible influences of age, gender, side and navigation system on patellar height were evaluated separately in subgroups.

Joint line changes after primary total knee arthroplasty: navigated versus non-navigated.

Purpose: Navigation has been introduced to achieve more accurate positioning of the implants after TKA. The scientific attention was mainly paid on limb alignment rather than restoration of the natural joint line. The aim of our study was to compare the accuracy of the joint line restoration in primary TKA with and without navigation.