Comparative in vitro treatment of mesenchymal stromal cells with GDF-5 and R57A induces chondrogenic differentiation while limiting chondrogenic hypertrophy.

Purpose: Hypertrophic cartilage is an important characteristic of osteoarthritis and can often be found in patients suffering from osteoarthritis. Although the exact pathomechanism remains poorly understood, hypertrophic de-differentiation of chondrocytes also poses a major challenge in the cell-based repair of hyaline cartilage using mesenchymal stromal cells (MSCs). While different members of the transforming growth factor beta (TGF-β) family have been shown to promote chondrogenesis in MSCs, the transition into a hypertrophic phenotype remains a problem.

PMMA Bone Cement: Antibiotic Elution and Mechanical Properties in the Context of Clinical Use.

This literature review discusses the use of antibiotic loaded polymethylmethacrylate bone cements in arthroplasty. The clinically relevant differences that have to be considered when antibiotic loaded bone cements (ALBC) are used either for long-term implant fixation or as spacers for the treatment of periprosthetic joint infections are outlined. In this context, in vitro findings for antibiotic elution and material properties are summarized and transferred to clinical use.

The Impact of Total Knee Replacement with a Customized Cruciate-Retaining Implant Design on Patient-Reported and Functional Outcomes.

Purpose: To treat patients with tricompartimental knee osteoarthritis (OA), a customized cruciate-retaining total knee arthroplasty (CCR-TKA) system can be used, including both individualized instrumentation and implants. The objective of this monocentric cohort study was to analyze patient-reported and functional outcomes in a series of patients implanted with the second generation of this customized implant.

Methods: At our arthroplasty center, we prospectively recruited a cohort of patients with tricompartmental gonarthrosis to be treated with total knee replacement (TKA) using a customized cruciate-retaining (CCR) implant design.

Patient-specific cruciate-retaining total knee replacement with individualized implants and instruments (iTotal™ CR G2).

Objective: Treatment of tricompartimental osteoarthritis (OA) using customized instruments and implants for cruciate-retaining total knee arthroplasty. Use of patient-specific instruments and implants (ConforMIS iTotal CR G2) together with a 3D-planning protocol (iView®). Retropatellar resurfacing is optional.

Accurate implant fit and leg alignment after cruciate-retaining patient-specific total knee arthroplasty.

Background: For improved outcomes in total knee arthroplasty (TKA) correct implant fitting and positioning are crucial. In order to facilitate a best possible implant fitting and positioning patient-specific systems have been developed. However, whether or not these systems allow for better implant fitting and positioning has yet to be elucidated.

Different types of cartilage neotissue fabricated from collagen hydrogels and mesenchymal stromal cells via SOX9, TGFB1 or BMP2 gene transfer.

Objective: As native cartilage consists of different phenotypical zones, this study aims to fabricate different types of neocartilage constructs from collagen hydrogels and human mesenchymal stromal cells (MSCs) genetically modified to express different chondrogenic factors.

Design: Human MSCs derived from bone-marrow of osteoarthritis (OA) hips were genetically modified using adenoviral vectors encoding sex-determining region Y-type high-mobility-group-box (SOX) 9, transforming growth factor beta (TGFB) 1 or bone morphogenetic protein (BMP) 2 cDNA, placed in type I collagen hydrogels and maintained in serum-free chondrogenic media for three weeks. Control constructs contained unmodified MSCs or MSCs expressing GFP.

The human arthritic hip joint is a source of mesenchymal stromal cells (MSCs) with extensive multipotent differentiation potential.

Background: While multiple in vitro studies examined mesenchymal stromal cells (MSCs) derived from bone marrow or hyaline cartilage, there is little to no data about the presence of MSCs in the joint capsule or the ligamentum capitis femoris (LCF) of the hip joint. Therefore, this in vitro study examined the presence and differentiation potential of MSCs isolated from the bone marrow, arthritic hyaline cartilage, the LCF and full-thickness samples of the anterior joint capsule of the hip joint.

Methods: MSCs were isolated and multiplied in adherent monolayer cell cultures.

Characterization of human telomerase reverse transcriptase immortalized anterior cruciate ligament cell lines.

Background: The anterior-cruciate-ligament (ACL) contains mesenchymal stem cells (ACL-MSCs), suggesting the feasibility of regenerative treatments of this tissue. The immortalization of isolated cells results in cell-lines applicable to develop cell-based therapies. Immortal cell lines eliminate the need for frequent cell isolation from donor tissues.

Editorial Commentary: Subacromial Bursa-Friend or Foe Within The Shoulder? An Old Debate With New Insights.

There is an ongoing debate about whether to resect or preserve the subacromial bursa during surgical treatment of rotator cuff tears. Neer was the first to systematically describe bursitis as a component of subacromial impingement syndrome that may extend to rotator cuff disease, often discussed as a point of controversy with Uhthoff who first identified the bursa as a contributor to rotator cuff healing, both experimentally and clinically. Because the subacromial bursa provides the gliding mechanism of the shoulder and regenerates itself after surgical removal, interest evolved on the role of the bursa in the healing of rotator cuff tears for evolution of regenerative therapies as a support of arthroscopic repair techniques.

Tendon-derived stem cells from the long head of the biceps tendon: Inflammation does not affect the regenerative potential.

Objectives: The long head of the biceps (LHB) is often resected in shoulder surgery and could therefore serve as a cell source for tissue engineering approaches in the shoulder. However, whether it represents a suitable cell source for regenerative approaches, both in the inflamed and non-inflamed states, remains unclear. In the present study, inflamed and native human LHBs were comparatively characterized for features of regeneration.

High variability of proximal tibial asymmetry and slope: a CT data analysis of 15,807 osteoarthritic knees before TKA.

Purpose: As the correct rotational and sagittal alignment of the tibial tray are of key importance for optimal total knee arthroplasty (TKA) function, the objective of this study was to determine these individual variations in the proximal tibial geometry in terms of posterior tibial slope (PTS) and tibial surface asymmetry by analysing a large dataset of computer tomography (CT) information.

Methods: A retrospective two-part review was performed on 15,807 datasets that were generated during the design phase for a customized TKA implant. First, 15807 CAD (computer-aided-design) models derived from CT data were used to conduct the analysis on the variation of the PTS.

What Is the Possible Impact of High Variability of Distal Femoral Geometry on TKA? A CT Data Analysis of 24,042 Knees.

Background: Previous studies analyzing femoral components of TKAs have demonstrated the limited ability of these components to accommodate size variations seen in the patient population, particularly width and femoral offset.

Questions/purposes: The purpose of this study was to use a large data set of knee CT scans (1) to determine the variations in the distal and posterior femoral geometries and to determine whether there is a correlation between distal condylar offset and posterior femoral offset as a potential parameter for symmetry/asymmetry; and (2) to evaluate what proportion of knees would have a substantial mismatch between the implant's size or shape and the patient's anatomy if a femoral component of a modern standard TKA of symmetric (sTKA) or asymmetric (asTKA) designs were to be used.

Methods: A retrospective study was performed on 24,042 data sets that were generated during the design phase for a customized TKA implant.

Antibiotic elution and compressive strength of gentamicin/vancomycin loaded bone cements are considerably influenced by immersion fluid volume.

The effect of doubling the immersion fluid (eluate) volume on antibiotic concentrations and on mechanical stability from vancomycin and gentamicin loaded bone cements was investigated in vitro. Antibiotic loaded bone cements containing premixed 1.34% gentamicin antibiotic concentration in the cement powder (wt), premixed 1.

Comparison of Elution Characteristics and Compressive Strength of Biantibiotic-Loaded PMMA Bone Cement for Spacers: Copal® Spacem with Gentamicin and Vancomycin versus Palacos® R+G with Vancomycin.

Purpose: Copal® spacem is a new PMMA bone cement for fabricating spacers. This study compares elution of gentamicin, elution of vancomycin, and compressive strength of Copal® spacem and of Palacos® R+G at different vancomycin loadings in the powder of the cements. We hypothesized that antibiotic elution of Copal® spacem is superior at comparable compressive strength.

Evaluation of implant fit and frontal plane alignment after bi-compartmental knee arthroplasty using patient-specific instruments and implants.

Introduction: The goals of successful bi-compartmental knee arthroplasty are to achieve correct fit and positioning of the implant, while appropriately correcting the mechanical alignment of the leg after surgery. As these requirements are not always reliably fulfilled using off-the-shelf implant systems, newer approaches for bi-compartmental resurfacing have been explored.

Material And Methods: In this article we report the radiographic results of 30 patients with anteromedial osteoarthritis (OA) who were treated with a novel patient-specific fixed-bearing bi-compartmental knee resurfacing system using custom-made implants and instruments.

TGF-β1-Modified Hyaluronic Acid/Poly(glycidol) Hydrogels for Chondrogenic Differentiation of Human Mesenchymal Stromal Cells.

In cartilage regeneration, the biomimetic functionalization of hydrogels with growth factors is a promising approach to improve the in vivo performance and furthermore the clinical potential of these materials. In order to achieve this without compromising network properties, multifunctional linear poly(glycidol) acrylate (PG-Acr) is synthesized and utilized as crosslinker for hydrogel formation with thiol-functionalized hyaluronic acid via Michael-type addition. As proof-of-principle for a bioactivation, transforming growth factor-beta 1 (TGF-β1) is covalently bound to PG-Acr via Traut's reagent which does not compromise the hydrogel gelation and swelling behavior.

Mesenchymal Stem Cells Isolated from the Anterior Cruciate Ligament: Characterization and Comparison of Cells from Young and Old Donors.

Purpose: Mesenchymal stem cells (MSCs) isolated from the anterior cruciate ligament (ACL) share multiple characteristics of bone marrow-derived mesenchymal stem cells (BMSCs), allowing their use for regenerative therapies. Injuries to the ACL can affect people of all ages. This study assesses whether the regenerative potential of ACL-derived MSCs (ACL-MSCs) from old donors is as high as the potential of ACL-MSCs from young donors.

The Mayo conservative hip: complication analysis and management of the first 41 cases performed at a University level 1 department.

Background: To prevent bone loss in hip arthroplasty, several short stem systems have been developed, including the Mayo conservative hip system. While there is a plethora of data confirming inherent advantages of these systems, only little is known about potential complications, especially when surgeons start to use these systems.

Methods: In this study, we present a retrospective analysis of the patients' outcome, complications and the complication management of the first 41 Mayo conservative hips performed in 37 patients.

Rescued Chondrogenesis of Mesenchymal Stem Cells under Interleukin 1 Challenge by Foamyviral Interleukin 1 Receptor Antagonist Gene Transfer.

Mesenchymal stem cells (MSCs) and their chondrogenic differentiation have been extensively investigated as MSCs provide an attractive source besides chondrocytes for cartilage repair therapies. Here we established prototype foamyviral vectors (FVV) that are derived from apathogenic parent viruses and are characterized by a broad host range and a favorable integration pattern into the cellular genome. As the inflammatory cytokine interleukin 1 beta (IL1β) is frequently present in diseased joints, the protective effects of FVV expressing the human interleukin 1 receptor antagonist protein (IL1RA) were studied in an established model (aggregate culture system) of chondrogenesis in the presence of IL1β.

Loading with vancomycin does not decrease gentamicin elution in gentamicin premixed bone cement.

Antibiotic loaded bone cements are used as drug delivery systems for the treatment of periprosthetic joint infections. They can be loaded with antibiotics during industrial component production (premixing) and during cement preparation (manually blending). Although double premixed antibiotic loaded bone cements are available, manually blending of a gentamicin premixed antibiotic loaded bone cement with vancomycin is still popular.

Case report - calcification of the medial collateral ligament of the knee with simultaneous calcifying tendinitis of the rotator cuff.

Background: Calcification of the medial collateral ligament (MCL) of the knee is a very rare disease. We report on a case of a patient with a calcifying lesion within the MCL and simultaneous calcifying tendinitis of the rotator cuff in both shoulders.

Case Presentation: Calcification of the MCL was diagnosed both via x-ray and magnetic resonance imaging (MRI) and was successfully treated surgically.

Nail-patella-syndrome in a young patient followed up over 10 years: relevance of the sagittal trochlear septum for patellofemoral pathology.

Introduction: Nail-patella-syndrome (NPS) is a rare autosomal-dominant inherited disease with pathologies of nails, skeleton, kidneys, and eyes. Linkage to a mutated gene was found. It codes for the transcription-factor LMX1B.

Investigation of Migration and Differentiation of Human Mesenchymal Stem Cells on Five-Layered Collagenous Electrospun Scaffold Mimicking Native Cartilage Structure.

Cartilage degeneration is the major cause of chronic pain, lost mobility, and reduced quality of life for over estimated 150 million osteoarthritis sufferers worldwide. Despite intensive research, none of the available therapies can restore the hyaline cartilage surface beyond just fibrous repair. To overcome these limitations, numerous cell-based approaches for cartilage repair are being explored that aim to provide an appropriate microenvironment for chondrocyte maintenance and differentiation of multipotent mesenchymal stem cells (MSCs) toward the chondrogenic lineage.

[Total knee arthroplasty. Patient-specific instruments and implants].

This article describes the concept and surgical technique of patient-specific total knee arthroplasty. Patient-specific implants and instruments are designed and fabricated based on computed tomography (CT) data of the leg. The disposable patient-specific drill guides and cutting-jigs are manufactured taking into consideration the anatomical and biomechanical axes of the knee joint and mediating the efficient pre-navigation of the osseous saw-cuts, without the need for additional navigation or balancing aids.

The Wuerzburg procedure: the tensor fasciae latae perforator is a reliable anatomical landmark to clearly identify the Hueter interval when using the minimally-invasive direct anterior approach to the hip joint.

Background: The key for successful delivery in minimally-invasive hip replacement lies in the exact knowledge about the surgical anatomy. The minimally-invasive direct anterior approach to the hip joint makes it necessary to clearly identify the tensor fasciae latae muscle in order to enter the Hueter interval without damaging the lateral femoral cutaneous nerve. However, due to the inherently restricted overview in minimally-invasive surgery, this can be difficult even for experienced surgeons.