Personalized Fiber-Reinforcement Networks for Meniscus Reconstruction.

The menisci are fibrocartilaginous tissues that are crucial to the load-sharing and stability of the knee, and when injured, these properties are compromised. Meniscus replacement scaffolds have utilized the circumferential alignment of fibers to recapitulate the microstructure of the native meniscus; however, specific consideration of size, shape, and morphology has been largely overlooked. The purpose of this study was to personalize the fiber-reinforcement network of a meniscus reconstruction scaffold.

Achieving molecular orientation in thermally extruded 3D printed objects.

Three-dimensional (3D) printing is used to fabricate tissue scaffolds. Polymer chains in these objects are typically unoriented. The mechanical properties of these scaffolds can be significantly enhanced by proper alignment of polymer chains.

Biomechanical characterization of a novel collagen-hyaluronan infused 3D-printed polymeric device for partial meniscus replacement.

The menisci transmit load by increasing the contact area and decreasing peak contact stresses on the articular surfaces. Meniscal lesions are among the most common orthopedic injuries, and resulting meniscectomies are associated with adverse polycaprolactone contact mechanics changes and, ultimately, an increased likelihood of osteoarthritis. Meniscus scaffolds were fabricated by 3D-printing a network of circumferential and radial filaments of resorbable polymer (poly(desaminotyrosyl-tyrosine dodecyl ester dodecanoate)) and infused with collagen-hyaluronan.

Partial Meniscus Replacement with a Collagen-Hyaluronan Infused Three-Dimensional Printed Polymeric Scaffold.

The only FDA-approved partial meniscus scaffold, the Collagen Meniscus Implant (CMI), is not approved for reimbursement by government and only reimbursable by certain private insurers. Scaffolds with improved mechanical properties and greater efficacy are needed. A previous study (Ghodbane, DOI: 10.

Tissue-Engineered Total Meniscus Replacement With a Fiber-Reinforced Scaffold in a 2-Year Ovine Model.

Background: Meniscus injuries and associated meniscectomies cause patients long-term pain and discomfort and can lead to joint deterioration.

Purpose: To evaluate a collagen-hyaluronan sponge reinforced with synthetic resorbable polymer fiber for total meniscus reconstruction in a long-term ovine model.

Study Design: Controlled laboratory study.

Interference Screw Versus Suture Endobutton Fixation of a Fiber-Reinforced Meniscus Replacement Device in a Human Cadaveric Knee Model.

Background: Meniscal lesions represent one of the most common intra-articular knee injuries. Meniscus replacement devices are needed to restore load distribution and knee stability after meniscectomy. Fixation of these devices is crucial to the generation of hoop stresses and the distribution of loads in the joint.

Carbodiimide cross-linking counteracts the detrimental effects of gamma irradiation on the physical properties of collagen-hyaluronan sponges.

Collagen-based scaffolds are extensively used in biomaterials and tissue engineering applications. These scaffolds have shown great biocompatibility and versatility, but their relatively low mechanical properties may limit use in orthopaedic load-bearing applications. Moreover, terminal sterilization with gamma irradiation, as is commonly performed with commercial devices, presents concerns over structural integrity and enzymatic stability.

The Ovine Model for Meniscus Tissue Engineering: Considerations of Anatomy, Function, Implantation, and Evaluation.

Meniscus injuries represent one of the most-common intra-articular knee injuries. The current treatment options include meniscectomy and allograft transplantation, both with poor long-term outcomes. Therefore, there is a need for regenerative techniques to restore meniscal function.

Negative Outcomes of Poly(l-Lactic Acid) Fiber-Reinforced Scaffolds in an Ovine Total Meniscus Replacement Model.

Our objective was to test the efficacy of collagen-hyaluronan scaffolds reinforced with poly(l-lactic acid) (PLLA) fibers in an ovine total meniscus replacement model. Scaffolds were implanted into 9 sheep (n = 1 at 8 weeks, n = 2 at 16 weeks, n = 3 at both 24, 32 weeks) following total medial meniscectomy. From 16 weeks on, explants were characterized by confined compression creep, histological, and biochemical analyses.

Physical and mechanical properties of cross-linked type I collagen scaffolds derived from bovine, porcine, and ovine tendons.

Collagen scaffolds are often utilized in tissue engineering applications where their performance depends on physical and mechanical properties. This study investigated the effects of collagen source (bovine, porcine, and ovine tendon) on properties of collagen sponge scaffolds cross-linked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS). Scaffolds were tested for tensile and compressive properties, stability (resistance to enzymatic degradation), pore size, and swelling ratio.

One-Year Outcomes of Total Meniscus Reconstruction Using a Novel Fiber-Reinforced Scaffold in an Ovine Model.

Background: Meniscus injuries and resulting meniscectomies lead to joint deterioration, causing pain, discomfort, and instability. Tissue-engineered devices to replace the meniscus have not shown consistent success with regard to function, mechanical integrity, or protection of cartilage.

Purpose: To evaluate a novel resorbable polymer fiber-reinforced meniscus reconstruction scaffold in an ovine model for 52 weeks and assess its integrity, tensile and compressive mechanics, cell phenotypes, matrix organization and content, and protection of the articular cartilage surfaces.

Successful Total Meniscus Reconstruction Using a Novel Fiber-Reinforced Scaffold: A 16- and 32-Week Study in an Ovine Model.

Background: Meniscus injuries in the United States result in an estimated 850,000 surgical procedures each year. Although meniscectomies are the most commonly performed orthopaedic surgery, little advancement has been made in meniscus replacement and regeneration, and there is currently no total meniscus replacement device approved by the Food and Drug Administration.

Hypothesis: A novel fiber-reinforced meniscus scaffold can be used as a functional total meniscus replacement.

Fetal and neonatal exposure to the endocrine disruptor, methoxychlor, reduces lean body mass and bone mineral density and increases cortical porosity.

Endogenous estrogen has beneficial effects on mature bone and negatively affects the developing skeleton, whereas the effect of environmental estrogens is not known. Methoxychlor (MXC) is a synthetic estrogen known as a persistent organochlorine and used as a pesticide. Methoxychlor and its metabolites display estrogenic, anti-estrogenic and anti-androgenic activity and may therefore influence bone.

Development of a silk and collagen fiber scaffold for anterior cruciate ligament reconstruction.

The objective of this study was to determine a silk-collagen fiber ratio for an anterior cruciate ligament (ACL) reconstruction composite scaffold device. Composite fiber scaffolds with silk volumes ≥14 % and collagen volume <86 % demonstrated comparable or greater initial ultimate tensile stress relative to the human ACL. Silk scaffolds implanted subcutaneously and intraarticularly in rabbits demonstrated an 84 and 92 % reduction in strength with a 26 and 22 % reduction in volume after 8 weeks, respectively.

Sterilization of tendon allografts: a method to improve strength and stability after exposure to 50 kGy gamma radiation.

Terminal sterilization of tendon allografts with high dose gamma irradiation has deleterious effects on tendon mechanical properties and stability after implantation. Our goal is to minimize these effects with radio protective methods. We previously showed that radio protection via combined crosslinking and free radical scavenging maintained initial mechanical properties of tendon allografts after irradiation at 50 kGy.

Design and mechanical evaluation of a novel fiber-reinforced scaffold for meniscus replacement.

A fiber-reinforced degradable scaffold for replacement of meniscal tissue was designed, fabricated, and mechanically evaluated. The hypotheses were that (1) the fiber network design would share a portion of compressive loads via the generation of circumferential tensile loads, and (2) the scaffold tensile properties would be similar to those of the meniscus. Two meniscus scaffold designs varying in fiber content (1000 or 500 fibers: MS1000, MS500) underwent cyclic compressive loading up to 100 and 250N, with resultant tensile loads measured at the anterior and posterior anchors.

Exogrip: assisted hand strength glove - biomed 2011.

A large number of American troops fighting in Afghanistan and Iraq have received wounds in their upper extremities leading to significant nerve damage and loss of strength. These injuries impair their ability to perform day-to-day tasks such as lifting a cup of coffee or opening a door. Although the cause of some injuries in service-people is often unique to their employment, civilian employees in other industries are also plagued with similar physical damage due to other kinds of injuries.

A comparison of degradable synthetic polymer fibers for anterior cruciate ligament reconstruction.

We compared mechanical properties, degradation rates, and cellular compatibilities of two synthetic polymer fibers potentially useful as ACL reconstruction scaffolds: poly(desaminotyrosyl-tyrosine dodecyl dodecanedioate)(12,10), p(DTD DD) and poly(L-lactic acid), PLLA. The yield stress of ethylene oxide (ETO) sterilized wet fibers was 150 +/- 22 MPa and 87 +/- 12 MPa for p(DTD DD) and PLLA, respectively, with moduli of 1.7 +/- 0.

Improved tendon radioprotection by combined cross-linking and free radical scavenging.

Allograft safety is a great concern owing to the risk of disease transmission from nonsterile tissues. Radiation sterilization is not used routinely because of deleterious effects on the mechanical integrity and stability of allograft collagen. We previously reported several individual cross-linking or free radical scavenging treatments provided some radioprotective effects for tendons.

Radioprotection of tendon tissue via crosslinking and free radical scavenging.

Ionizing radiation could supplement tissue bank screening to further reduce the probability of diseases transmitted by allografts if denaturation effects can be minimized. It is important, however, such sterilization procedures be nondetrimental to tissues. We compared crosslinking and free radical scavenging potential methods to accomplish this task in tendon tissue.

Mechanical stimulation of tendon tissue engineered constructs: effects on construct stiffness, repair biomechanics, and their correlation.

The objective of this study was to determine how in vitro mechanical stimulation of tissue engineered constructs affects their stiffness and modulus in culture and tendon repair biomechanics 12 weeks after surgical implantation. Using six female adult New Zealand White rabbits, autogenous tissue engineered constructs were created by seeding mesenchymal stem cells (0.1 x 10(6) cells/ml) in collagen gel (2.

The effect of autologous mesenchymal stem cells on the biomechanics and histology of gel-collagen sponge constructs used for rabbit patellar tendon repair.

The objective of this study was to introduce mesenchymal stem cells (MSCs) into a gel-sponge composite and examine the effect the cells have on repair biomechanics and histology 12 weeks postsurgery. We tested two related hypotheses-adding MSCs would significantly improve repair biomechanics and cellular organization, and would result in higher failure forces than peak in vivo patellar tendon (PT) forces recorded for an inclined hopping activity. Autogenous tissue-engineered constructs were created by seeding MSCs from 15 adult rabbits at 0.

Factors that influence transgene expression and cell viability on DNA-PEI-seeded collagen films.

Gene delivery from tissue-engineering devices has the potential to improve healing, but better regulation of the level and duration of gene expression is needed. We hypothesized that transgene expression could be controlled by varying the fabrication and soaking parameters used in making collagen- based gene delivery scaffolds. Collagen films were made from acid-insoluble type I bovine dermal collagen and seeded with plasmid DNA encoding firefly luciferase, complexed with polyethylenimine.

Changes in mechanical properties and cellularity during long-term culture of collagen fiber ACL reconstruction scaffolds.

Resorbable scaffolds for anterior cruciate ligament (ACL) reconstruction should provide temporary mechanical function then gradually breakdown while promoting matrix synthesis by local cells. Crosslinking influences collagen's mechanical properties, degradation rate, and interactions with cells. Our objective was to compare the effects of different crosslinkers on cellularity and mechanical properties during long-term (8 week) culture of collagen fiber scaffolds.

Development of cell-seeded patellar tendon allografts for anterior cruciate ligament reconstruction.

Patellar tendon (PT) allografts for anterior cruciate ligament (ACL) reconstruction are potentially immunogenic and incorporate slowly compared with autografts. Our tissue-engineering approach to improve allograft efficacy is to (1) remove intrinsic cells from the graft to reduce antigenicity and then (2) seed the graft with extrinsic cells to improve ligamentization. To remove cells, tendons were soaked in 1% extraction solutions of tri(n-butyl)phosphate (TBP) or sodium dodecyl sulfate (SDS) for various time periods (24-72 h) and rinsed exhaustively.