Soft Tissue Repair Research Articles

Electrospun Nanofibrous Scaffolds: Review of Current Progress in the Properties and Manufacturing Process, and Possible Applications for COVID-19.

Over the last twenty years, researchers have focused on the potential applications of electrospinning, especially its scalability and versatility. Specifically, electrospun nanofiber scaffolds are considered an emergent technology and a promising approach that can be applied to biosensing, drug delivery, soft and hard tissue repair and regeneration, and wound healing. Several parameters control the functional scaffolds, such as fiber geometrical characteristics and alignment, architecture, etc. As it is based on nanotechnology, the concept of this approach has shown a strong evolution in terms of the forms of the materials used (aerogels, microspheres, etc.), the incorporated microorganisms used to treat diseases (cells, proteins, nuclei acids, etc.), and the manufacturing process in relation to the control of adhesion, proliferation, and differentiation of the mimetic nanofibers. However, several difficulties are still considered as huge challenges for scientists to overcome in relation to scaffolds design and properties (hydrophilicity, biodegradability, and biocompatibility) but also in relation to transferring biological nanofibers products into practical industrial use by way of a highly efficient bio-solution. In this article, the authors review current progress in the materials and processes used by the electrospinning technique to develop novel fibrous scaffolds with suitable design and that more closely mimic structure. A specific interest will be given to the use of this approach as an emergent technology for the treatment of bacteria and viruses such as COVID-19.

Effect of Ulnar Head Offset on Distal Radioulnar Joint Stability

A complete ulnar head replacement may be indicated in cases of distal radial ulnar joint (DRUJ) dysfunction to address bony pathology in lieu of using a constrained total DRUJ prosthesis. Complete ulnar head implants are simple, but they may be unstable if soft tissue tension is not adequately restored. We hypothesized that incorporating an increased offset in the complete ulnar head replacement would lead to increased tension on the distal oblique interosseous ligament, increased contact force at the DRUJ, and improved joint stability. Using a specially designed jig, we measured instability by comparing displacement under load (stiffness) of the DRUJ in 10 cadaveric specimens under 4 different conditions: (1) intact, (2) native head after excision of the triangular fibrocartilage complex, (3) replacement of the ulnar head with a standard offset ulnar head, and (4) replacement of the ulnar head with an increased offset ulnar head. No soft tissue repair was done. We measured anteroposterior displacement under load with maximum translation of 10 mm or maximum loads of 50 N. We tested all specimens with the forearm positioned in neutral, supination, and pronation. Excising the triangular fibrocartilage complex decreased the average stiffness of the DRUJ to 46% of the intact state, creating a simulated state of DRUJ instability. Replacing the ulnar head with the standard offset head increased average stiffness to 54% of the intact state. Increasing the ulnar head offset with the simulated total ulnar head replacement increased average stiffness to 77% of the intact state. An increased offset ulnar head replacement improves DRUJ stability compared with a standard anatomic offset ulnar head replacement. Understanding DRUJ morphology and offset is important in the treatment of DRUJ arthritis and instability.

In situ Adipogenesis in Biomaterials Without Cell Seeds: Current Status and Perspectives.

For cosmetic and reconstructive purposes in the setting of small-volume adipose tissue damage due to aging, traumatic defects, oncological resections, and degenerative diseases, the current strategies for soft tissue replacement involve autologous fat grafts and tissue fillers with synthetic, bioactive, or tissue-engineered materials. However, they all have drawbacks such as volume shrinkage and foreign-body responses. Aiming to regenerate bioactive vascularized adipose tissue on biomaterial scaffolds, adipose tissue engineering (ATE) has emerged as a suitable substitute for soft tissue repair. The essential components of ATE include scaffolds as support, cells as raw materials for fat formation, and a tolerant local environment to allow regeneration to occur. The commonly loaded seeding cells are adipose-derived stem cells (ASCs), which are expected to induce stable and predictable adipose tissue formation. However, defects in stem cell enrichment, such as donor-site sacrifice, limit their wide application. As a promising alternative approach, cell-free bioactive scaffolds recruit endogenous cells for adipogenesis. In biomaterials without cell seeds, the key to sufficient adipogenesis relies on the recruitment of endogenous host cells and continuous induction of cell homing to scaffolds. Regeneration, rather than repair, is the fundamental dominance of an optimal mature product. To induce in situ adipogenesis, many researchers have focused on the mechanical and biochemical properties of scaffolds. In addition, efforts to regulate an angiogenic and adipogenic microenvironment in cell-free settings involve integrating growth factors or extracellular matrix (ECM) proteins onto bioactive scaffolds. Despite the theoretical feasibility and encouraging results in animal models, few of the reported cell-free biomaterials have been tested in humans, and failures of decellularized adipose tissues in adipogenesis have also been reported. In these cases, the most likely reason was the lack of supporting vasculature. This review summarizes the current status of biomaterials without cell seeds. Related mechanisms and influencing factors of in situ adipogenesis in cell-free biomaterials, dilemma in the development of biomaterials, and future perspectives are also addressed.

Mechanisms of Soft Tissue Injury and Repair from Ballistics

Projectile injuries to the face deserve particular attention to evaluate for involvement of critical structures and functional elements and treat the devastating effects on facial aesthetics. Ballistic trauma to the maxillofacial region often has significant soft tissue and bony defects, creating a greater challenge to the reconstructive surgeon. The main goals of treatment of projectile injuries to the face are decreasing the amount of contaminants and nonviable tissue at the site, ensuring functionality, and restoring aesthetic appearance. There exists a lack of robust research on the subject. Soft tissue injuries from high-velocity projectiles have changed the perspective on treating acute injuries to the face and neck. Injuries encountered during both Operation Iraqi Freedom and Operation Enduring Freedom give the author pause to reflect upon a different wounding pattern than that encountered in stateside trauma centers. Given the dissemination of high-velocity weaponry by enemy combatants such as the improvised explosive device, mortar round, and high-velocity rifles, a higher incidence of facial wounds has been reported. The mechanism of injury and a stepwise approach for surgical repair are discussed incorporating advanced trauma life support principles and a reconstructive ladder of repair.

CORR Insights®: Does Adding Femoral Lengthening at the Time of Rotation Hip Transposition After Periacetabular Tumor Resection Allow for Restoration of Limb Length and Function? Interim Results of a Modified Hip Transposition Procedure.

CORR Insights®: Does Adding Femoral Lengthening at the Time of Rotation Hip Transposition After Periacetabular Tumor Resection Allow for Restoration of Limb Length and Function? Interim Results of a Modified Hip Transposition Procedure.

The adjunct use of lateral hinged external fixator in the treatment of traumatic destabilizing elbow injuries.

The purpose of this study is to evaluate the results of using a lateral hinged external fixator as an adjunct stabilizer in the treatment of a variety of acute destabilizing elbow injuries. A retrospective review was performed on the medical records of patients in whom a lateral monolateral elbow hinged external fixator was applied by the senior author. The indication to apply the fixator corresponded to a variety of acute injury patterns ranging from simple elbow trauma or dislocation to complex fracture-dislocation, and the decision was based on either the presence of recurrent or persistent instability in any direction and/or to secure a vulnerable or weak bony fixation or soft tissue repair as intra-operatively judged by the surgeon. The fixator was inserted in the same setting after the repair of the associated ligamentous and/or bony structures. Patients operated after one month of the trauma and those presented with open elbow injury or associated humeral or ulnar shaft fracture were excluded. Rehabilitation was immediately started and the fixator removed at six to eightweeks with elbow testing and gentle manipulation under general anaesthesia, and resuming of rehabilitation after removal. Clinical assessment was performed for all patients according to the Mayo Elbow Performance Score (MEPS) with evaluation of range of motion at regular intervals till the end of the post-operative first year, then at final follow-up for the purpose of the study with radiographic assessment for evaluation of elbow reduction and concentricity. There were 13 patients with a mean age of 42 years. Two patients had instability secondary to LCL rupture; one patient had redislocation because of associated coronoid process fracture; one patient had radial head fracture with rupture of both collateral ligaments; five patients had terrible triad injury with variable association of collateral ligaments lesions; and four patients had posterior Monteggia fracture-dislocation. The mean MEPS was 90 at a mean follow-up of seven years with six excellent, six good, and one fair result. All patients had a concentrically reduced and stable elbow as assessed clinically and radiologically with a mean functional arc of motion of 132° for extension-flexion and 178° for pronation-supination. The hinged elbow external fixator represents a valuable adjunct in the therapeutic arsenal for the treatment of unstable elbows after bony and soft tissue repair. It provides satisfactory results in terms of stability and function and should be available in the operating room when a surgeon treats a complex elbow dislocation or fracture-dislocation.

Bioactive Materials for Soft Tissue Repair.

Over the past decades, age-related pathologies have increased abreast the aging population worldwide. The increased age of the population indicates that new tools, such as biomaterials/scaffolds for damaged tissues, which display high efficiency, effectively and in a limited period of time, for the regeneration of the body's tissue are needed. Indeed, scaffolds can be used as templates for three-dimensional tissue growth in order to promote the tissue healing stimulating the body's own regenerative mechanisms. In tissue engineering, several types of biomaterials are employed, such as bioceramics including calcium phosphates, bioactive glasses, and glass–ceramics. These scaffolds seem to have a high potential as biomaterials in regenerative medicine. In addition, in conjunction with other materials, such as polymers, ceramic scaffolds may be used to manufacture composite scaffolds characterized by high biocompatibility, mechanical efficiency and load-bearing capabilities that render these biomaterials suitable for regenerative medicine applications. Usually, bioceramics have been used to repair hard tissues, such as bone and dental defects. More recently, in the field of soft tissue engineering, this form of scaffold has also shown promising applications. Indeed, soft tissues are continuously exposed to damages, such as burns or mechanical traumas, tumors and degenerative pathology, and, thereby, thousands of people need remedial interventions such as biomaterials-based therapies. It is known that scaffolds can affect the ability to bind, proliferate and differentiate cells similar to those of autologous tissues. Therefore, it is important to investigate the interaction between bioceramics and somatic/stem cells derived from soft tissues in order to promote tissue healing. Biomimetic scaffolds are frequently employed as drug-delivery system using several therapeutic molecules to increase their biological performance, leading to ultimate products with innovative functionalities. This review provides an overview of essential requirements for soft tissue engineering biomaterials. Data on recent progresses of porous bioceramics and composites for tissue repair are also presented.

Indocyanine green angiography technique assisted brachial artery perforator propeller flap to repair soft tissue defects of trunk and upper limb

To explore the feasibility of using indocyanine green (ICG) angiography to detect brachial artery perforators, and the clinical application of brachial artery perforator propeller (BAPP) flaps to repair soft tissue defects of the trunk and upper limbs. Between August 2016 and February 2019, ICG angiography was used to detect the perforating vessels of the brachial artery muscle septum, and the BAPP flaps were cut out with the detected perforating vessels as the pedicle to repair 19 cases of trunk and upper limb soft tissue defects. There were 12 males and 7 females, with an average age of 28.6 years (range, 5-66 years). Etiologies included the post-burn scar in 10 cases, soft-tissue sarcoma in 5 cases, congenital melanocytic nevi in 2 cases, chronic chest wall ulcer in 1 case, and malignant melanoma in 1 case. Defects located in axilla in 8 cases, chest wall in 4 cases, elbow in 5 cases, and shoulder in 2 cases. The area of the defect ranged from 15 cm×3 cm to 20 cm×8 cm. Pre-transfer tissue expansion was used in 11 patients. Thirteen flaps were pedicled with 1 perforator vessel, and 6 flaps were pedicled with 2 perforator vessels. The length of the vascular pedicle was 2.5-4.5 cm, with an average of 3.08 cm. The area of the skin flap ranged from 11 cm×5 cm to 22 cm×10 cm. The flap rotation angle was 110° in 1 case, 120° in 1 case, and 180° in 17 cases. Except for one donor site repaired by skin graft, the other donor sites were directly sutured. A total of 24 perforating vessels of the brachial artery muscle septum were detected by ICG angiography, 26 were identified during the operation, with an accuracy rate of 92.31%. Eighteen flaps survived without arteriovenous crisis. Venous congestion was observed in the distal 3-cm of one flap and the flap survived after conservative management. Intraoperative analysis showed that the blood perfusion of the distal 4-cm of one flap was poor, the relative value was less than 32%, the flap survived after removing the poor perfusion area. All the patients were followed up 3 to 23 months (mean, 8.6 months). The color and texture of the flap were similar to those of the recipient area. Flap debulking was not needed in all patients owing to the thinness of the flap. The contracture symptoms of patients with scar contracture on the medial of the elbow joint and axilla were significantly improved; a patient with malignant melanoma underwent tumor resection at 1 year and 5 months after operation due to tumor recurrence, and additional surgery was done to remove the recurrent tumor. No tumor recurrence was found in other patients. The ICG angiography technique can be used to explore the perforating vessels of the brachial artery muscle septum. The BAPP flap pedicled with the perforating vessels can be used for the repair of skin and soft tissue defects in the chest wall, axilla, shoulder, and elbow joint.

Preparation and Properties of Silk Fibroin Electro Hydrogels via a Low Voltage Electrostatic Field

Protein hydrogels is an important biomaterial for soft tissue repair in biomedical applications. However, the most extracellular matrixes are structured and ordered, the morphology of common hydrogels are of random network structures that impeded their applications in tissue engineering. In this study, silk fibroin hydrogels with different morphologies (i.e., microspheres, regularized beads, nano/micro fibers, intertwined networks, and multi-walls) were prepared under low voltage electrostatic fields by regulating the concentration of silk fibroin solution. Additionally, their stability can be regulated with further processing routes to satisfy the tailored requirements for different applications. Fourier transform infrared spectrometer (FTIR) and X-ray diffraction (XRD) provided evidence of the stability of silk fibroin electro materials was tuned by this method effectively. Therefore, these silk fibroin electro hydrogels with various morphologies, high orientation, and stability-regulatable properties provided a promising candidate for tissue engineering.

Fabrication and Characterization of the Core-Shell Structure of Poly(3-Hydroxybutyrate-4-Hydroxybutyrate) Nanofiber Scaffolds.

Tissue engineering scaffolds with nanofibrous structures provide positive support for cell proliferation and differentiation in biomedical fields. These scaffolds are widely used for defective tissue repair and drug delivery. However, the degradation performance and mechanical properties of scaffolds are often unsatisfactory. Here, we successfully prepared a novel poly(3-hydroxybutyrate-4-hydroxybutyrate)/polypyrrole (P34HB-PPy) core-shell nanofiber structure scaffold with electrospinning and in situ surface polymerization technology. The obtained composite scaffold showed good mechanical properties, hydrophilicity, and thermal stability based on the universal material testing machine, contact angle measuring system, thermogravimetric analyzer, and other methods. The results of the in vitro bone marrow-derived mesenchymal stem cells (BMSCs) culture showed that the P34HB-PPy composite scaffold effectively mimicked the extracellular matrix (ECM) and exhibited good cell retention and proliferative capacity. More importantly, P34HB is a controllable degradable polyester material, and its degradation product 3-hydroxybutyric acid (3-HB) is an energy metabolite that can promote cell growth and proliferation. These results strongly support the application potential of P34HB-PPy composite scaffolds in biomedical fields, such as tissue engineering and soft tissue repair.

Implications of Free Temporoparietal Fascial Flap Reconstruction in the Pediatric Population.

The temporoparietal fascial flap (TPFF) is a versatile tool that can be used in the reconstruction of head and neck and distal upper and lower extremity defects. The TPFF may be harvested as a pedicle or free flap as well as with the temporalis muscle and/or adjacent calvarial bone as a composite flap. As a free flap, the TPFF has been used as a joint gliding surface with coverage of nerves and tendons, for extremity soft tissue repair, for tracheal and pharyngeal coverage and for defects of the nose, scalp, and auricle. This article focuses on the use of the free TPFF in the pediatric population through systemic review of the medical literature. Current perspectives on the use of this flap and microsurgery in general in pediatric patients are addressed.

Biomaterials in Regenerative Medicine

Physiological regenerative system of human body is incapable of restoring the function when an injury exceeds its normal limits. Conventional methods previously being used for repair and rejuvenation of tissues had certain limitations that have brought the biomaterials to the forefront in the area of regenerative medicine. Biomaterials provide optimal support to the tissue during the process of healing and remodeling. Numerous classes of biomaterials are focused on specific applications; most prominent among them are polymers. Biomaterials are now being used in several areas such as fabrication, hematology and blood cell substitutes, tissue engineering, extracorporeal artificial organs, bone and vascular regeneration, stem cell differentiation and soft tissue repair. However, for the success of biomaterials in regenerative medicine , the focus should not only be on the physical, mechanical and chemical properties of the materials but also the fundamental principles of biological interactions and biocompatibility.

Time- and Dose-Dependent Effects of Pulsed Ultrasound on Dermal Repair in Diabetic Mice

Chronic wounds, including diabetic, leg and pressure ulcers, impose a significant health care burden worldwide. Some evidence indicates that ultrasound can enhance soft tissue repair. However, therapeutic responses vary among individuals, thereby limiting clinical translation. Here, effects of pulsed ultrasound on dermal wound healing were assessed using a murine model of chronic, diabetic wounds. An ultrasound exposure system was developed to provide daily ultrasound exposures to full-thickness, excisional wounds in genetically diabetic mice. Wounds were exposed to 1 MHz ultrasound (2 ms pulse, 100 Hz pulse repetition frequency, 0–0.4 MPa) for 2 or 3 wk. Granulation tissue thickness and wound re-epithelialization increased as a function of increasing ultrasound pressure amplitude. At 2 wk after injury, significant increases in granulation tissue thickness and epithelial ingrowth were observed in response to 1 MHz pulsed ultrasound at 0.4 MPa. Wounds exposed to 0.4 MPa ultrasound for 3 wk were characterized by collagen-dense, revascularized granulation tissue with a fully restored, mature epithelium. Of note, only half of wounds exposed to 0.4 MPa ultrasound showed significant granulation tissue deposition after 2 wk of treatment. Thus, the db+/db+ mouse model may help to identify biological variables that influence individual responses to pulsed ultrasound and accelerate clinical translation.

Management of Grade 3C Compound Injury of Lower Limb with Floating Knee – Salvage versus Amputation (Case Series)

Introduction:Severe open injuries of limbs, especially of the femur and tibia when associated with vascular injuries, present major challenges in management. The decision to amputate or salvage can often be a difficult one even for experienced surgeons. Mangled lower extremity results due to high-energy trauma, especially due to motor vehicle accidents, and is defined as injury to three of the four systems in the extremity that is soft tissues, bone, vascular, and nerve. Open fractures are classified by Gustilo and Anderson’s classification in which type 3B is an injury where soft-tissue loss and primary closure of the wound are not possible and type 3C is any open fracture with vascular compromise.Case Report:We report a series of six ipsilateral fractures of the femur and the tibia treated at the Department of Orthopaedics, Sri Ramachandra Medical College and Hospital, Chennai, Tamil Nadu, over a 3-year period (2014–2017). The mean age of our patients was 30 years old, and there were five men and one woman. The right side lower limb was frequently involved (five cases), and the main etiology was road traffic accidents (six cases). Articular involvement was found in six cases. Skin wounds were noticed in all cases (type III C of the Gustilo classification). Urgent wound care, fluid replacement, and antibiotic therapy were undertaken for open fractures. According to modified Fraser classification, all six cases was classified under type II-C. Mangled extremity severity score for five cases was 7 and for one case it was 8. Ganga Hospital Open Injury Severity Score was also used which was found to be in borderline range of 16 score for three cases, 15 score for two cases, and 14 score for one case. All six cases were managed with serial wound debridement + Ilizarov fixator + soft-tissue repair with involvement of orthopedic, vascular, and plastic surgery team. Limb salvage was done for all six cases after considering all the factors. Postoperatively, rehabilitative care and physiotherapy in the form of non-weight-bearing mobilization with walker support was given to all patients. The patients were followed up for the period of 2 years and doing symptomatically better. Based on current literature guidelines and evidence-based medicine, management for borderline cases is proposed to aid clinical decision-making in these situations.Conclusion:With great effort and good team work (like vascular and orthopedic surgeons), badly comminuted compound injuries (Type III C injury) can be managed well with Ilizarov fixation. Even though the decision of amputation versus salvage was based on more scientific/scoring system, patient’s option should be taken, especially in borderline cases considering the present medicolegal scenario.

Receptor mimicking TGF-β1 binding peptide for targeting TGF-β1 signaling.

Prolonged and elevated transforming growth factor-β1 (TGF-β1) signaling can lead to undesired scar formation during tissue repair and fibrosis that is often a result of chronic inflammation in the lung, kidney, liver, heart, skin, and joints. We report new TGF-β1 binding peptides that interfere with TGF-β1 binding to its cognate receptors and thus attenuate its biological activity. We identified TGF-β1 binding peptides from the TGF-β1 binding domains of TGF-β receptors and engineered their sequences to facilitate chemical conjugation to biomaterials using molecular docking simulations. The in vitro binding studies and cell-based assays showed that RIPΔ, which was derived from TGF-β type I receptor, bound TGF-β1 in a sequence-specific manner and reduced the biological activity of TGF-β1 when the peptide was presented either in soluble form or conjugated to a commonly used synthetic biomaterial. This approach may have implications for clinical applications such as treatment of various fibrotic diseases and soft tissue repair and offer a design strategy for peptide antibodies based on the biomimicry of ligand-receptor interactions.

Management of severe iatrogenic perineal injury

Perineal injuries are uncommon. More uncommon are severe perineal injuries. This is attributed to the relative protection of the perineum by the bony pelvis. Common causes of perineal injury include injuries from motor vehicular accidents, fall from height, foreign body insertion into the perineum, injuries from rape, and penetrating external trauma. The management of severe perineal injury entails addressing any life-threatening condition in the patient first and, subsequently, the perineal injury. The perineal injury can be repaired primarily with or without colostomy or colostomy carried out alone without primary repair. We present four cases of severe perineal injury managed by colostomy alone without primary repair of perineal soft tissue or anal sphincters. The anal sphincters and perineal soft tissues healed secondarily and sealed without any need for repair with good outcome.

Return to Sport Following Open Latarjet Procedure for Recurrent Shoulder Instability

Shoulder instability is common within athletic populations, particularly in contact sports. The Latarjet procedure is typically reserved for recurrent instability recalcitrant to soft tissue repair. Limited literature exists regarding return-to-sport following Latarjet stabilization.

Dehydrated Human Amnion-Chorion Product as an Adjunct to Scaling and Root Planing inMaintenance Patients: A Pilot Study

Background: Adjunctive therapies are often combined with Scaling and Root Planing (SRP) procedures to limit bacterial recolonization of periodontal pockets and to modulate the wound healing environment. While local delivery antimicrobial therapies are effective, they do not promote soft tissue repair at these sites. BioXclude, a dehydrated human de-epithelialized amnion-chorion membrane product (ddACM) sourced from donated human placental tissue, has been shown to have antimicrobial properties, contain stimulatory growth factors known to activate wound healing processes, and possess critical attachment substrates for cellular adhesion and migration. Given this combination, it was hypothesized that ddACM would be an effective adjunctive therapy for the treatment of periodontal pockets following SRP procedures. Methods: Sixteen non-smoking patients, compliant with a regular periodontal maintenance program, were included in this study. A total of 30 sites showing a ≥ 2 mm increase in periodontal probing depth (PPD), with associated bleeding on probing (BOP), were chosen for treatment. Following standard SRP procedures with local anesthesia, ddACM was placed into the treated area. A six-week periodontal re-evaluation was completed, with the primary outcome variable being PD reduction and secondary outcomes that included resolution of bleeding on probing (BOP). Results: Mean PD reduction was 2.55 mm ± 0.34 mm, with three sites showing ≥ 4 mm ± 0.2 mm reduction in PD. BOP was resolved in 83% of the treated sites. Conclusion: ddACM provides significant benefit as an adjunctive therapy to SRP for the treatment of periodontal pockets in terms of PD reduction and resolution of BOP.

Técnica de Eden Hybinette en inestabilidad anterior de hombro con pérdida de stock óseo en paciente con epilepsia: reporte de caso

Shoulder instability is occasionally associated with glenoid bone loss in patients with epilepsy. There have been few articles that describe specific surgical treatments for this type of injury. This case report shows a successful surgical approach used in an epileptic patient with multiple right shoulder dislocations that occurred mainly during seizures, through the Eden Hybinette technique, performed using an iliac crest autograft. The patient has been followed up for one year postoperatively, without new episodes of right shoulder dislocation, without complaints of pain, with good range of movement of the shoulder without limitations for daily or work activities. Different surgical methods have been published for these patients, including soft tissue repair operations, as well as skeletal reconstructions with bone graft, Eden Hybinette being one of these. This surgery is a valid option, since it allows an adequate position of the graft in the glenoid defect, potentially reducing the risk of neurovascular and myotendinous lesions; although, more importantly, it reduces the recurrences of shoulder dislocation in patients with uncontrolled epilepsy and gives them the opportunity for a good quality of life.Evidence Level: IV

Three dimensional porous scaffolds derived from collagen, elastin and fibrin proteins orchestrate adipose tissue regeneration

Current gold standard to treat soft tissue injuries caused by trauma and pathological condition are autografts and off the shelf fillers, but they have inherent weaknesses like donor site morbidity, immuno-compatibility and graft failure. To overcome these limitations, tissue-engineered polymers are seeded with stem cells to improve the potential to restore tissue function. However, their interaction with native tissue is poorly understood so far. To study these interactions and improve outcomes, we have fabricated scaffolds from natural polymers (collagen, fibrin and elastin) by custom-designed processes and their material properties such as surface morphology, swelling, wettability and chemical cross-linking ability were characterised. By using 3D scaffolds, we comprehensive assessed survival, proliferation and phenotype of adipose-derived stem cells in vitro. In vivo, scaffolds were seeded with adipose-derived stem cells and implanted in a rodent model, with X-ray microtomography, histology and immunohistochemistry as read-outs. Collagen-based materials showed higher cell adhesion and proliferation in vitro as well as higher adipogenic properties in vivo. In contrast, fibrin demonstrated poor cellular and adipogenesis properties but higher angiogenesis. Elastin formed the most porous scaffold, with cells displaying a non-aggregated morphology in vitro while in vivo elastin was the most degraded scaffold. These findings of how polymers present in the natural polymers mimicking ECM and seeded with stem cells affect adipogenesis in vitro and in vivo can open avenues to design 3D grafts for soft tissue repair.