Biomechanical Properties of Repair Cartilage Tissue Are Superior Following Microdrilling Compared to Microfracturing in Critical Size Cartilage Defects.

Background/aim: Common surgical treatment options for large focal chondral defects (FCDs) in the knee include microfracturing (MFX) and microdrilling (DRL). Despite numerous studies addressing MFX and DRL of FDCs, no in vivo study has focused on biomechanical analysis of repair cartilage tissue in critical size FCDs with different amounts of holes and penetration depths.

Materials And Methods: Two round FCDs (d=6 mm) were created on the medial femoral condyle in 33 adult merino sheep.

The synovial fluid calprotectin lateral flow test for the diagnosis of chronic prosthetic joint infection in failed primary and revision total hip and knee arthroplasty.

Purpose: The diagnostic criteria of prosthetic joint infection (PJI) recommended by the most commonly used diagnostic algorithms can be obscured or distorted by other inflammatory processes or aseptic pathology. Furthermore, the most reliable diagnostic criteria are garnered during revision surgery. A robust, reliable addition to the preoperative diagnostic cascade is warranted.

Modular Augmentation in Varus-Valgus-Constrained Knee Arthroplasty-Do We Need Sleeves to Avoid Femoral Loosening After Excessive Distal Augmentation?

Background: In revision total knee arthroplasty, zonal fixation methods with a combination of augments, press-fit stems, and sleeves are popular. We hypothesized that high distal femoral augmentation with diaphyseal press-fit stems leads to an increased rate of early aseptic loosening and that femoral metaphyseal sleeves improve implant survival. Therefore, we retrospectively investigated implant survival in relation to augment heights and sleeves.

Synovial calprotectin is a reliable biomarker for periprosthetic joint infections in acute-phase inflammation - a prospective cohort study.

Purpose: Diagnosing periprosthetic joint infections (PJI) are challenging and may be hampered by the presence of other causes of local inflammation. Conventional synovial and serum markers are not reliable under these circumstances. Synovial calprotectin has been recently shown as a promising biomarker for PJI in total hip (THA) and total knee arthroplasty (TKA).

Diagnostic accuracy of multiplex polymerase chain reaction on tissue biopsies in periprosthetic joint infections.

The diagnosis and treatment of periprosthetic joint infection (PJI) currently relies on cultures, which are time-consuming and often fail. Multiplex PCR assays promise reliable and prompt results, but have been heterogeneously evaluated. In this study, we analyse multiplex PCR in pathogen identification using only tissue biopsies.

Surgeons' expectations of osteotomies around the knee.

Introduction: High tibial osteotomy (HTO) is a valid and joint preserving surgical technique to treat medial degenerative osteoarthritis (OA) in young and active patients. A recent study shows that patients' expectations of osteotomy around the knee are high, but OA progression and potential conversion to a total knee arthroplasty (TKA) were underestimated. The aim of this study was to investigate surgeons' expectations of HTO and to compare the results to the patients' expectations and actual outcomes reported in the literature.

Rifampicin has - Compared to clindamycin - A dose and time dependent effect on hMSCs during osteogenic differentiation .

Background: The effects of rifampicin and clindamycin on human mesenchymal stromal cell (hMSC) were examined.

Methods: hMSC were cultured with rifampicin and clindamycin (0.5 μg/ml, 5 μg/ml, 50 μg/ml) and examinations of proliferation (Bromodeoxyuridine), calcification (Alizarin red) and mineralization (alkaline phosphatase) were performed after 7th, 14th and 21st days.

SOX9 Knockout Induces Polyploidy and Changes Sensitivity to Tumor Treatment Strategies in a Chondrosarcoma Cell Line.

As most chemotherapeutic drugs are ineffective in the treatment of chondrosarcoma, we studied the expression pattern and function of SOX9, the master transcription factor for chondrogenesis, in chondrosarcoma, to understand the basic molecular principles needed for engineering new targeted therapies. Our study shows an increase in SOX9 expression in chondrosarcoma compared to normal cartilage, but a decrease when the tumors are finally defined as dedifferentiated chondrosarcoma (DDCS). In DDCS, SOX9 is almost completely absent in the non-chondroid, dedifferentiated compartments.

Revision Arthroplasty Through the Direct Anterior Approach Using an Asymmetric Acetabular Component.

Despite increasing numbers of primary hip arthroplasties performed through the direct anterior approach (DAA), there is a lack of literature on DAA revision arthroplasty. The present study was performed in order to evaluate outcomes and revision rates after revision through the DAA using an asymmetric acetabular component with optional intra- and extramedullary fixation. In a retrospective cohort study, we analyzed prospectively collected data of 57 patients (61 hips, 43 female, 18 male) who underwent aseptic acetabular component revision through the DAA with the abovementioned implant system between January 2015 and December 2017.

Diagnostic accuracy of MRI with metal artifact reduction for the detection of periprosthetic joint infection and aseptic loosening of total hip arthroplasty.

Purpose: To evaluate imaging characteristics obtained from magnetic resonance imaging (MRI) with metal artifact reduction (MAR) to differentiate between periprosthetic joint infection (PJI), aseptic loosening and cases without these pathologies after total hip arthroplasty (THA).

Methods: Patients with THA (n = 41; mean age 66.4 ± 9.

Antimicrobial peptides in human synovial membrane as (low-grade) periprosthetic joint infection biomarkers.

Background: Safe diagnosis of periprosthetic joint infection (PJI) is of utmost importance for successful exchange arthroplasty. However, current diagnostic tools show insufficient accuracy in the clinically common and challenging chronic low-grade infections. To close this diagnostic gap, reliable (bio)markers display the most promising candidates.

Improved pre-operative diagnostic accuracy for low-grade prosthetic joint infections using second-generation multiplex Polymerase chain reaction on joint fluid aspirate.

Background: A major obstacle for the treatment of prosthetic joint infection (PJI) is the identification of the underlying causative organism. While the diagnostic criteria ruling PJI in or out have become ever more accurate, the detection of the causative pathogen(s) still relies mostly on conventional and time-consuming microbial culture. The aim of this study was to evaluate the diagnostic potential of a second-generation multiplex PCR assay (Unyvero ITI G2, Curetis AG, Holzgerlingen, Germany) used on synovial fluid specimens.

Inhibition of PLK1 by capped-dose volasertib exerts substantial efficacy in MDS and sAML while sparing healthy haematopoiesis.

Introduction: Targeting the cell cycle machinery represents a rational therapeutic approach in myelodysplastic syndromes (MDS) and secondary acute myeloid leukemia (sAML). Despite substantial response rates, clinical use of the PLK inhibitor volasertib has been hampered by elevated side effects such as neutropenia and infections.

Objectives: The primary objective was to analyse whether a reduced dose of volasertib was able to limit toxic effects on the healthy haematopoiesis while retaining its therapeutic effect.

Guided and Unguided Biopsy in the Diagnostic of Periprosthetic Infections of the Knee - Evaluation of an Evidence-based Algorithm.

Background: Periprosthetic joint infection (PPI) is one of the most common reasons for revision in total knee arthroplasty (TKA). Percutaneous synovial biopsy is considered as a well-established diagnostic tool in ambiguous cases of chronic pain after TKA. The exact number of undetected low-grade infections remains unclear.

Venetoclax with azacitidine targets refractory MDS but spares healthy hematopoiesis at tailored dose.

Patients with Myelodysplastic Syndromes (MDS) and secondary Acute Myeloid Leukemia (sAML) have a very poor prognosis after failure of hypomethylating agents (HMA). Stem cell transplantation is the only effective salvage therapy, for which only a limited number of patients are eligible due to age and comorbidity. Combination therapy of venetoclax and azacitidine (5-AZA) seems to be a promising approach in myeloid malignancies, but data from patients with HMA failure are lacking.

A humanized bone microenvironment uncovers HIF2 alpha as a latent marker for osteosarcoma.

The quest for predictive tumor markers for osteosarcoma (OS) has not well progressed over the last two decades due to a lack of preclinical models. The aim of this study was to investigate if microenvironmental modifications in an original humanized in vivo model alter the expression of OS tumor markers. Human bone micro-chips and bone marrow, harvested during hip arthroplasty, were implanted at the flanks of NOD/scid mice.

[Megaimplants of the Proximal Femur: Current Concepts].

In addition to their outstanding significance in the field of tumor orthopaedics, megaprostheses are becoming increasingly important for revision arthroplasty. Despite their wide application, the reported complication and failure rates remain high. The analysis of failure mechanisms roughly allows a breakdown into mechanical and non-mechanical causes; soft-tissue failure, loosening and periprosthetic infection play outstanding roles.

Improving results in rat fracture models: enhancing the efficacy of biomechanical testing by a modification of the experimental setup.

Background: Animal fracture models, primarily performed in rats, are crucial to investigate normal and pathological bone healing. However, results of biomechanical testing representing a major outcome measure show high standard deviations often precluding statistical significance. Therefore, the aim of our study was a systematical examination of biomechanical characteristics of rat femurs during three-point bending.

Humanization of bone and bone marrow in an orthotopic site reveals new potential therapeutic targets in osteosarcoma.

Background: Existing preclinical murine models often fail to predict effects of anti-cancer drugs. In order to minimize interspecies-differences between murine hosts and human bone tumors of in vivo xenograft platforms, we tissue-engineered a novel orthotopic humanized bone model.

Methods: Orthotopic humanized tissue engineered bone constructs (ohTEBC) were fabricated by 3D printing of medical-grade polycaprolactone scaffolds, which were seeded with human osteoblasts and embedded within polyethylene glycol-based hydrogels containing human umbilical vein endothelial cells (HUVECs).

Impact of Pathological Fractures on the Prognosis of Primary Malignant Bone Sarcoma in Children and Adults: A Single-Center Retrospective Study of 205 Patients.

Background: The purpose of this study was to investigate whether pathological fractures (PF) influence the prognosis of patients with osteosarcoma (OS) or Ewing tumor (ET) regarding 5-year survival, occurrence of metastases, and local recurrence.

Methods: We retrospectively analyzed 205 patients with metastatic and nonmetastatic OS or ET. Survival analysis was performed for all patients and differentiated for patients with OS (n = 127) and ET (n = 78) as well as for adults (n = 101) and children (n = 104).

Whole bone testing in small animals: systematic characterization of the mechanical properties of different rodent bones available for rat fracture models.

Objectives: Rat fracture models are extensively used to characterize normal and pathological bone healing. Despite, systematic research on inter- and intra-individual differences of common rat bones examined is surprisingly not available. Thus, we studied the biomechanical behaviour and radiological characteristics of the humerus, the tibia and the femur of the male Wistar rat-all of which are potentially available in the experimental situation-to identify useful or detrimental biomechanical properties of each bone and to facilitate sample size calculations.

Fully automated segmentation of callus by micro-CT compared to biomechanics.

Background: A high percentage of closed femur fractures have slight comminution. Using micro-CT (μCT), multiple fragment segmentation is much more difficult than segmentation of unfractured or osteotomied bone. Manual or semi-automated segmentation has been performed to date.

Increased Resistance of Skin Flora to Antimicrobial Prophylaxis in Patients Undergoing Hip Revision Arthroplasty.

Background/aim: Prosthetic joint infection (PJI) remains a major complication after total joint replacement and is the primary indication for revision arthroplasty. Specifically, coagulase-negative Staphylococci (CNS) can cause low-grade infections. Despite the use of cephalosporin-based antimicrobial prophylaxis (AMP) and antiseptic treatment at the surgical site, evidence suggests that a significant number of cases of dermal CNS results in low-grade PJI.