Achilles Tendon Defect Research Articles

Transosseous Flexor Hallucis Longus Tendon Transfer for Large Achilles Tendon Defects: Surgery Technique and Outcome.

Operative management of chronic Achilles tendinopathy with large defects can be surgically challenging. Concerns exist regarding transosseous transfer of the flexor hallucis longus (FHL) tendon because of the shortened lever arm of flexion and weakening of the big toe. The aim of this study was to demonstrate the 2-year outcome of transosseous FHL transfer for the treatment of large Achilles tendon defects. We retrospectively analyzed 28 patients who underwent FHL transfer. The extent of the defect was measured with magnetic resonance imaging. Outcome parameters were the German Foot Function Index (FFI-D) evaluated at baseline and 6, 12, and 24 months postoperatively, the University of California-Los Angeles (UCLA) activity scale, 2 questions about patient satisfaction, reports on complications, or plantar flexion weakness of the great toe. Mean FFI-D scores of pain and disability improved from 37.2 and 52.3, respectively, at baseline to 6.9 and 15.0, respectively, 24 months postsurgery. (P < .001). At 24 months, 57% of patients were very satisfied and 25% were satisfied with the current symptoms related to their Achilles tendon. All patients noted a relevant improvement at the 2 year follow-up; 1 patient noted weakness of big toe flexion without relevant functional limitation. Complications occurred in 3 patients in the initial postoperative course (2 with delayed wound healing, and 1 with severe perifocal wound necrosis); all resolved completely. We found transosseous FHL transfer using the long, open harvest method and additional bridging of large Achilles defects to be a successful treatment. The majority of patients experienced a significant improvement in both function and pain level and were satisfied with the outcome. Flexion weakness of the big toe does not appear to be a clinically relevant issue after this treatment for chronic Achilles tendinopathy.

Clinical Evaluation of The Use of PRP as A Treatment for Achilles Tendon Defects in Dog Model

Clinical Evaluation of The Use of PRP as A Treatment for Achilles Tendon Defects in Dog Model

Effects of Platelets Rich Plasma and N Acetyl Cysteine on Achilles Tendon Regeneration in Dog

Background: The Achilles tendon is one of the most important tendons in the body. When any problem or defect occurs, such as (cut, tear or puncture), it may hinder the motor functions of the foot. The recent study highlights the effective role of N_acetyl cysteine and Platelet_rich plasma in accelerating the healing process of the tendon. Aim of the Study: The present study aimed to study and compare the effects of Platelets rich plasma and N acetyl cysteine on Achilles tendon regeneration after tendon defect inducing in dog. Materials and Methods: Fifteen adult dogs were utilized in this study , the dogs were divided into three groups(5 dogs for each one): Group A(PRP group) was treated with PRP topically on the tendon, Group B(N-AC group) in which tendon defect was treatedby topical application of N-acetylcysteine , while in Group C(control group ) the tendon defect was left without treatment.The animal was aneshtetized and the right hind limb was prepared for aspetic surgery , Achilles tendon defect was created by using needle 18 guage (core lesion) and the site of operation was closed routinally Achilles tendon healing and histopathological monitoring were evaluated at 42 days post-injury. Results:Throughout the study, the participants' general health was assessed daily. Results showed that tendon healing was more successful in the PRP- and NAC-treated tendon than in the untreated tendon, with significant improvement in the treated groups after 42 days. Discussion: Our study has shown that utilizing PRP and NAC for treating tendons is successful in preserving certain structural characteristics during the initial stage of tendon remodeling due to the growth factors in PRP and the NAC's capability in assisting TSPCs to survive and differentiate helps with tendon recovery after damage.

Integrating electrospun aligned fiber scaffolds with bovine serum albumin-basic fibroblast growth factor nanoparticles to promote tendon regeneration

BackgroundElectrospun nanofiber scaffolds have been widely used in tissue engineering because they can mimic extracellular matrix-like structures and offer advantages including high porosity, large specific surface area, and customizable structure. In this study, we prepared scaffolds composed of aligned and random electrospun polycaprolactone (PCL) nanofibers capable of delivering basic fibroblast growth factor (bFGF) in a sustained manner for repairing damaged tendons.ResultsAligned and random PCL fiber scaffolds containing bFGF-loaded bovine serum albumin (BSA) nanoparticles (BSA-bFGF NPs, diameter 146 ± 32 nm) were fabricated, respectively. To validate the viability of bFGF-loaded aligned PCL nanofiber scaffold (aPCL + bFGF group) in tendon tissue engineering, we assessed the in vitro differentiation of human amniotic mesenchymal stem cells (hAMSCs) towards a tenogenic lineage and the in vivo regeneration of tendons using a rat Achilles tendon defect model. The encapsulated bFGF could be delivered in a sustained manner in vitro. The aPCL + bFGF scaffold promoted the in vitro differentiation of human amniotic mesenchymal stem cells (hAMSCs) towards a tenogenic lineage. In the repair of a rat Achilles tendon defect model, the aPCL + bFGF group showed a better repair effect. The scaffold offers a promising substrate for the regeneration of tendon tissue.ConclusionsThe aligned and random PCL fiber scaffolds containing bFGF nanoparticles were successfully prepared, and their physical and chemical properties were characterized. The aPCL + bFGF scaffold could promote the expression of the related genes and proteins of tendon-forming, facilitating tendon differentiation. In the rat Achilles tendon defect experiments, the aPCL + bFGF exhibited excellent tendon regeneration effects.Graphical

Collagen scaffold-seeded iTenocytes accelerate the healing and functional recovery of Achilles tendon defects in a rat model.

Tendon injuries represent an ongoing challenge in clinical practice due to poor regenerative capacity, structure, and biomechanical function recovery of ruptured tendons. This study is focused on the assessment of a novel strategy to repair ruptured Achilles tendons in a Nude rat model using stem cell-seeded biomaterial. Specifically, we have used induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) overexpressing the early tendon marker Scleraxis (SCX, iMSCSCX+, iTenocytes) in combination with an elastic collagen scaffold. Achilles tendon defects in Nude rat models were created by isolating the tendon and excising 3mm of the midsection. The Achilles tendon defects were then repaired with iTenocyte-seeded scaffolds, unseeded scaffolds, or suture only and compared to native Nude rat tendon tissue using gait analyses, biomechanical testing, histology, and immunohistochemistry. The results show faster functional recovery of gait in iTenocyte-seeded scaffold group comparing to scaffold only and suture only groups. Both iTenocyte-seeded scaffold and scaffold only treatment groups had improved biomechanical properties when compared to suture only treatment group, however no statistically significant difference was found in comparing the cell seeding scaffold an scaffold only group in terms of biomechanical properties. Immunohistochemistry staining further demonstrated that iTenocytes successfully populated the collagen scaffolds and survived 9weeks after implantation in vivo. Additionally, the repaired tissue of iTenocyte-treated injuries exhibited a more organized structure when compared to tendon defects that were repaired only with suturing or unseeded scaffolds. We suggest that iTenocyte-seeded DuRepair™ collagen scaffold can be used as potential treatment to regenerate the tendon tissue biomechanically and functionally.

Carbon Fiber-Mediated Electrospinning Scaffolds Can Conduct Electricity for Repairing Defective Tendon.

Partial or complete rupture of the tendon can damage the collagen structure, resulting in the disruption of the electrical signal pathway. It is a great challenge to reconstruct the original electrical signal pathway of the tendon and promote the regeneration and functional recovery of defective tendon. In this study, carbon fiber-mediated electrospinning scaffolds were fabricated by wrapping conductive, high-strength, loose single-bundle carbon fibers with nanofiber membranes. Due to the presence of nanofiber membranes, the maximum tensile force of the scaffolds was 2.4 times higher than that of carbon fibers, while providing excellent temporal and spatial prerequisites for tenocytes to adapt to electrical stimulation to accelerate proliferation and expression. The diameter of the carbon fiber monofilaments used in this study was 5.07 ± 1.20 μm, which matched the diameter of tendon collagen, allowing for quickly establishing the connection between the tendon tissue and the scaffold, and better promoting the recovery of the electrical signal pathway. In a rabbit Achilles tendon defect repair model, the carbon fiber-mediated electrospinning scaffold was almost filled with collagen fibers compared to a nonconductive polyethylene glycol terephthalate scaffold. Transcriptome sequencing revealed that fibromodulin and tenomodulin expression were upregulated, and their related proteoglycans and glycosaminoglycan binding proteins pathways were enhanced, which could regulate the TGF-β signaling pathway and optimize the extracellular matrix assembly, thus promoting tendon repair. Therefore, the scaffold in this study makes up for the shortage of conductive scaffolds for repairing tendon defects, revealing the potential impact of conductivity on the signaling pathway of tendon repair and providing a new approach for future clinical studies.

Achilles tendon regeneration after experimental transverse tenotomy with preserved peritenon and the structures

Introduction The Ponseti method is the first choice for congenital clubfoot with the possibilities of transverse tenotomy being underexplored in repair of the Achilles tendon in pediatric patients.The objective was to identify specific features of the Achilles tendon repair after experimental transverse intersection and preserved peritenon, vessels and nerves of growing rabbits.Material and methods The experimental study included 20 Chinchilla rabbits of both sexes aged 1.0–1.5 months used as a biomodel with a weight of 1476.0 ± 114.3 g. Rabbits were sacrificed in groups of five by air embolism under local anesthesia at 15, 30, 60 and 90 days of surgery.Results The tendon defect zone was represented by small areas of dense fibrous scar tissue with some cellular fibroblasts, and tendon fibers of unremarkable architectonics arranged in a mutually parallel waves could be seen in the layers of connective tissue at 90 days. The thickness of the first-order collagen fibers increased to 8.9 ± 1.32 µm and comparison with the normal value of 9.2 ± 1.88 µm showed no statistically significant difference (p = 0.38). The thickness of the second-order collagen fibers increased to 28.1 ± 1.28 µm during the time, and comparison with the standard measurements of 28.3 ± 2.23 µm demonstrated no statistically significant difference (p = 0.64).Discussion According to the literature, the ability of the tenoblast to synthesize structural proteins and regulatory biomolecules after injury decreases with age and leads to fibrous restoration of the tendon and formation of a permanent scar. Our study on growing rabbits showed that the organotypic structure of the experimental tendon restored at the intersection site at 60 days with the Achilles tendon defect being represented by the tendon-like tissue at 90 days.Conclusion The Achilles tendon was shown to regenerate in optimal conditions after the dissection and preservation of the peritenon, vessels and nerves with tendon tissue being formed within a short time (3 months after the intervention) being identical to the original.

Structure, ingredient, and function-based biomimetic scaffolds for accelerated healing of tendon-bone interface

BackgroundTendon-bone interface (TBI) repair is slow and challenging owing to its hierarchical structure, gradient composition, and complex function. In this work, enlightened by the natural characteristics of TBI microstructure and the demands of TBI regeneration, a structure, composition, and function-based scaffold was fabricated. Methods: The biomimetic scaffold was designed based on the “tissue-inducing biomaterials” theory: (1) a porous scaffold was created with poly-lactic-co-glycolic-acid, nano-hydroxyapatite and loaded with BMP2-gelatinmp to simulate the bone (BP); (2) a hydrogel was produced from sodium alginate, type I collagen, and loaded with TGF-β3 to simulate the cartilage (CP); (3) the L-poly-lactic-acid fibers were oriented to simulate the tendon (TP). The morphology of tri-layered constructs, gelation kinetics, degradation rate, release kinetics and mechanical strength of the scaffold were characterized. Then, bone marrow mesenchymal stem cells (MSCs) and tenocytes (TT-D6) were cultured on the scaffold to evaluate its gradient differentiation inductivity. A rat Achilles tendon defect model was established, and BMSCs seeded on scaffolds were implanted into the lesionsite. The tendon-bone lesionsite of calcaneus at 4w and 8w post-operation were obtained for gross observation, radiological evaluation, biomechanical and histological assessment. ResultsThe hierarchical microstructures not only endowed the scaffold with gradual composition and mechanical properties for matching the regional biophysical characteristics of TBI but also exhibited gradient differentiation inductivity through providing regional microenvironment for cells. Moreover, the scaffold seeded with cells could effectively accelerate healing in rat Achilles tendon defects, attributable to its enhanced differentiation performance. ConclusionThe hierarchical scaffolds simulating the structural, compositional, and cellular heterogeneity of natural TBI tissue performed therapeutic effects on promoting regeneration of TBI and enhancing the healing quality of Achilles tendon. The translational potential of this articleThe novel scaffold showed the great efficacy on tendon to bone healing by offering a structural and compositional microenvironment. The results meant that the hierarchical scaffold with BMSCs may have a great potential for clinical application.

ADIPOSE CELLULAR INJECTION IN THE TREATMENT OF AN INTRASUBSTANCE ACHILLES TENDON TEAR

Introduction: We describe a case report of a patient who presented with chronic right Achilles tendon pain and weakness. Without contrast, magnetic resonance imaging of the right Achilles tendon revealed significant expansion of the Achilles tendon in the traverse and anteroposterior dimension with extensive increased T2 signal consistent with large partial-thickness Achilles tendon tear. A musculoskeletal ultrasound using a linear transducer demonstrated an anechoic tendon defect measuring 0.97 cm in the longitudinal axis with a total tendon length measuring 1.53 cm, as well as a 0.9 cm defect in the transverse axis surrounded by homogenous tendon fibers consistent with a large defect involving the distal Achilles tendon proximal to the distal insertion. The patient underwent an ultrasound-guided adipose cellular procedure using micronized fat to fill in the defect and facilitate pain reduction and tissue healing.Conclusion: Ultrasound-guided injection of micro-fragmented adipose tissue of Achilles tendon defect can result in significant improvement in pain and function

The current status and challenges of surgical treatment for chronic Achilles tendon rupture

With the growing demand for physical activity, an increasing number of individuals with chronic Achilles tendon ruptures are opting for surgical intervention. Surgical approaches encompass end-to end anastomosis, tendon flap techniques, tendon transfer procedures, and free tendon grafting, among others. When selecting the appropriate surgical method and determining the surgical indications, it is imperative to consider factors like the length of the Achilles tendon defect, patient age, aesthetic preferences, functional requirements, and local tissue conditions. As medical devices evolve and surgical techniques advance, the criteria for surgical intervention are also evolving. Drawing from existing literature evidence, it becomes crucial to define reasonable parameters for addressing Achilles tendon defects with each surgical technique, aligning more closely with clinical needs. Additionally, auxiliary technologies such as biologic therapy and innovative biomaterials have demonstrated promising results in laboratory or animal models. The focal point of advancing these auxiliary technologies lies in facilitating the translation of pertinent clinical outcomes in the future.

Salvage Reconstruction of a 12-cm Tendon Defect Following Chronic Achilles Rerupture-15-Year Follow-Up: A Case Report.

A 39-year-old man with a chronic Achilles rupture status post (1) failed primary repair and (2) secondary xenograft repair with graft rejection, resulting in a 12-cm Achilles tendon defect, which was reconstructed utilizing an Achilles bone block allograft and flexor hallucis longus (FHL) tendon transfer. At 15-year follow-up, the patient reported good functionality and satisfaction with the repair, with positive patient-reported outcome measures. Physical examination revealed excellent strength and range of motion. Magnetic resonance imaging confirmed the integrity and incorporation of the Achilles/FHL graft composite. This case study provides valuable insight into successful long-term management of complex chronic Achilles ruptures with large defects.

Chronic Achilles Tendon Avulsion Repair: Central Third Fascia Slide Technique with Flexor Hallucis Longus Transfer.

Chronic Achilles Tendon Avulsion Repair: Central Third Fascia Slide Technique with Flexor Hallucis Longus Transfer.

The Effects of Fibroblast Growth Factor-2 (FGF-2) on Achilles Tendon Injury

Category: Basic Sciences/Biologics; Ankle Introduction/Purpose: Achilles tendon defects are a challenging problem, and there is a need for new treatments. We investigated the use of Platelet-rich fibrin (PRF), a dense fibrin scaffold containing many growth factors and cytokines, for Achilles tendon injuries. The study found that PRF accelerates healing by promoting the proliferation and activation of tenocytes via FGF receptor/AKT signaling and TGF-β/SMAD3 signaling. While FGF-2, a growth factor in PRF, has been shown to promote tenocyte differentiation and proliferation, its effect on Achilles tendon injuries has not been reported. Therefore, this study aimed to investigate the effect of FGF-2 on Achilles tendon healing when administered alone and to determine its specific contribution to the healing process. Methods: We used a rat model of Achilles tendon defect. A 4-mm portion of the right Achilles tendon, 4 mm proximal to the calcaneal insertion, was resected to create a tendon defect. Gelatin hydrogel sheet (MedGel PI5) as a scaffold for PBS, FGF-2 (Rigroth®), and FGF receptor inhibitor (FGFRI: Pemigatinib) was placed into the gap before suturing it with nylon sutures. We observed HE-stained specimens at 200x and assessed histological healing by counting cells and vessels and grading cell morphology. The motor function was evaluated by the Basso, Beattie, and Bresnahan (BBB) score and the treadmill test. We compared the effects of FGF-2 on tenocytes isolated from rat Achilles tendons in the control, FGF2, and FGFRI groups. The proliferation and migration of tenocytes were measured by MTS assay and wound closure assay, respectively. Protein expression, such as Tenomodulin (Tnmd), Collagen Ⅰ, Ⅲ, and Screlaxis-A in cells, were evaluated by Western Blotting. Results: In the rat model, the number of cells, vessels and cell morphology scores at the defect sites increased in the FGF-2 group and decreased in the FGFRI group at 2 and 4 weeks postoperatively. In the motor functional evaluation, the FGF-2 group showed earlier improvement in the BBB score and the treadmill test compared to the control and FGFRI groups. The MTS assay showed that the number of viable cells was higher in the FGF-2 group and lower in the FGFRI group than in the control. Wound closure assay showed tenocyte migration was increased in the FGF-2 group and decreased in the FGFRI group. Regarding protein expression, Tnmd, Collagen I, III, and Screlaxis-A were increased in the FGF-2 group and decreased in the FGFRI group. Conclusion: In vivo, FGF-2 promoted healing of Achilles tendon injury, and FGFRI impeded it in terms of motor function and histology. Additionally, in vitro, FGF-2 promoted the proliferation and migration of tenocytes and enhanced extracellular matrix production, while FGFRI diminished these effects. Although native FGF-2 is produced at the injured site, further administration of FGF-2 accelerated Achilles tendon injury healing, while inhibiting the FGF receptor delayed recovery in this study. Therefore, FGF- 2 is very important in Achilles tendon injury healing and may promote recovery by enhancing angiogenesis, proliferation, and extracellular matrix production of tenocytes.

Tendon Repair and Regeneration Using Bioinspired Fibrillation Engineering That Mimicked the Structure and Mechanics of Natural Tissue.

Replicating the controlled nanofibrillar architecture of collagenous tissue represents a promising approach in the design of tendon replacements that have tissue-mimicking biomechanics─outstanding mechanical strength and toughness, defect tolerance, and fatigue and fracture resistance. Guided by this principle, a fibrous artificial tendon (FAT) was constructed in the present study using an engineering strategy inspired by the fibrillation of a naturally spun silk protein. This bioinspired FAT featured a highly ordered molecular and nanofibrillar architecture similar to that of soft collagenous tissue, which exhibited the mechanical and fracture characteristics of tendons. Such similarities provided the motivation to investigate FAT for applications in Achilles tendon defect repair. In vitro cellular morphology and expression of tendon-related genes in cell culture and in vivo modeling of tendon injury clearly revealed that the highly oriented nanofibrils in the FAT substantially promoted the expression of tendon-related genes combined with the Achilles tendon structure and function. These results provide confidence about the potential clinical applications of the FAT.

An Extracellular Vesicle-Cloaked Multifaceted Biocatalyst for Ultrasound-Augmented Tendon Matrix Reconstruction and Immune Microenvironment Regulation.

The healing of tendon injury is often hindered by peritendinous adhesion and poor regeneration caused by the accumulation of reactive oxygen species (ROS), development of inflammatory responses, and the deposition of type-III collagen. Herein, an extracellular vesicles (EVs)-cloaked enzymatic nanohybrid (ENEV) was constructed to serve as a multifaceted biocatalyst for ultrasound (US)-augmented tendon matrix reconstruction and immune microenvironment regulation. The ENEV-based biocatalyst exhibits integrated merits for treating tendon injury, including the efficient catalase-mimetic scavenging of ROS in the injured tissue, sustainable release of Zn2+ ions, cellular uptake augmented by US, and immunoregulation induced by EVs. Our study suggests that ENEVs can promote tenocyte proliferation and type-I collagen synthesis at an early stage by protecting tenocytes from ROS attack. The ENEVs also prompted efficient immune regulation, as the polarization of macrophages (Mφ) was reversed from M1φ to M2φ. In a rat Achilles tendon defect model, the ENEVs combined with US treatment significantly promoted functional recovery and matrix reconstruction, restored tendon morphology, suppressed intratendinous scarring, and inhibited peritendinous adhesion. Overall, this study offers an efficient nanomedicine for US-augmented tendon regeneration with improved healing outcomes and provides an alternative strategy to design multifaceted artificial biocatalysts for synergetic tissue regenerative therapies.

Nanofiber matrix formulations for the delivery of Exendin-4 for tendon regeneration: In vitro and in vivo assessment.

Tendon and ligament injuries are the most common musculoskeletal injuries, which not only impact the quality of life but result in a massive economic burden. Surgical interventions for tendon/ligament injuries utilize biological and/or engineered grafts to reconstruct damaged tissue, but these have limitations. Engineered matrices confer superior physicochemical properties over biological grafts but lack desirable bioactivity to promote tissue healing. While incorporating drugs can enhance bioactivity, large matrix surface areas and hydrophobicity can lead to uncontrolled burst release and/or incomplete release due to binding. To overcome these limitations, we evaluated the delivery of a peptide growth factor (exendin-4; Ex-4) using an enhanced nanofiber matrix in a tendon injury model. To overcome drug surface binding due to matrix hydrophobicity of poly(caprolactone) (PCL)-which would be expected to enhance cell-material interactions-we blended PCL and cellulose acetate (CA) and electrospun nanofiber matrices with fiber diameters ranging from 600 to 1000nm. To avoid burst release and protect the drug, we encapsulated Ex-4 in the open lumen of halloysite nanotubes (HNTs), sealed the HNT tube endings with a polymer blend, and mixed Ex-4-loaded HNTs into the polymer mixture before electrospinning. This reduced burst release from ∼75% to ∼40%, but did not alter matrix morphology, fiber diameter, or tensile properties. We evaluated the bioactivity of the Ex-4 nanofiber formulation by culturing human mesenchymal stem cells (hMSCs) on matrix surfaces for 21 days and measuring tenogenic differentiation, compared with nanofiber matrices in basal media alone. Strikingly, we observed that Ex-4 nanofiber matrices accelerated the hMSC proliferation rate and elevated levels of sulfated glycosaminoglycan, tendon-related genes (Scx, Mkx, and Tnmd), and ECM-related genes (Col-I, Col-III, and Dcn), compared to control. We then assessed the safety and efficacy of Ex-4 nanofiber matrices in a full-thickness rat Achilles tendon defect with histology, marker expression, functional walking track analysis, and mechanical testing. Our analysis confirmed that Ex-4 nanofiber matrices enhanced tendon healing and reduced fibrocartilage formation versus nanofiber matrices alone. These findings implicate Ex-4 as a potentially valuable tool for tendon tissue engineering.

The Healing Effect of Biodegradable Scaffolds Treated with Bone-Marrow Obtained Mesenchymal Stem Cells on Major Tendon Damage in the Dog as a Model.

The present study aimed to evaluate the implantation of decellularized small intestinal submucosa- extracellular matrix )SIS-ECM( seeded with bone marrow mesenchymal stem cells (BM-MSCs) to repair full-thickness Achilles tendon defect. For this purpose, 20 healthy adult stray dogs aged 8-12 months old (15±3 kg of weight) were enrolled in this study under an aseptic environment and general anesthesia. A 1.5 cm-long segment-based resection was performed in the mid-substance of the Achilles tendon in the control group (n=10) that did not receive treatment. While, in the experimental group (n=10), regarding the defect of the tendon, the stumps were bridged with decellularized SIS seeded with BM-MSCs (5×106) cells implanted. Afterward, the stumps of the tendon were sutured using the modified Kessler technique (4-0) polypropylene thread. The biomechanical observations of the tendon defect showed an increase in the tensile strength in the experimental group, compared to the control animals. It should be mentioned that this difference was significant (P≤0.05). Histopathological observations of biopsies harvested after the 4th, 8th, and 12th weeks revealed that the implanted graft had seeded with MSCs enhanced high-quality cellular infiltration and the host tissue healing was improved. Similar to the normal tendon, a dense organized collagenous tissue with high cellularity and vascularity was observed due to the presence of the remodeled ECM. However, the arrangement of collagen-fiber-derived connective tissue appeared to be more dominant than that in the experimental group, with less adhesion in the 12th week post-treatment. These findings suggest that the BM-MSCs inoculated with SIS can be employed to repair a damaged Achilles tendon due to the fact that this combination enhances the regeneration of the affected tendon.

Free composite and chimeric anterior lateral thigh flaps in covering secondary soft tissue defect after tumor resection: an overview from the medical literature to clinical applications

ABSTRACT Objective: To evaluate the results of soft tissue defect treatment with ALT composite flaps in covering secondary soft tissue defects after radical tumors resection. Method: From October 2017 to April 2023, we performed a series of 10 single-stage surgeries using composite anterior lateral thigh flap to cover secondary tissue defects in 2 cases covered Achilles tendon defects and 8 cases covered secondary defects after resection of tumors. In all patients with complex, multi-site secondary defects, in patients with secondary defects after resection of the head of the face, the defects are often complex, multi-plane, and multi-site, requiring the use of flaps flexibly and practicably to provide the best postoperative results for the patient. In 10 clinical cases, complex or clustered anterior femoral flaps were selected, and the pedicle and perforating artery branches were identified by hand-held Doppler. The identification of the perforating branches also helps to define the bounds of the flap. The flap is thinned if too thick. Microsurgery anastomosis was performed before the defect was covered. Result: The size of the ALT flap ranges from 10 x 5cm to 15 x12 cm and the size of the Fascia lata (FL) flap ranges from 7 x 4 cm to 10 x 8 cm. The average peduncle length for skin flap and muscle flap is about 2.5-5 cm and about 3.5- 7 cm, respectively. The thickness of the flap is about 6-13mm. After 3 months of surgery, all flaps are completely alive, close results of flaps are good, distant results are good with stable wound healing, most patients are satisfied with flap color, soft flap site, normal limb function. Conclusion: The free ALT composite chimeric flaps become a viable and flexible option for single-stage, threedimensional reconstruction of complex organ defects after tumor resection, by reducing the number of surgeries and the number of anastomosis. Improving treatment results for complex defects after cancer resection as well as reduce surgery and treatment time.

Graft and Flap: Orthoplastic Approach to Achilles Tendon Secondary Rupture.

Achilles tendon rupture represents one of the most common tendon ruptures. Although primary repair remains the treatment of choice, surgical complications, such as secondary rupture and tendon exposure, require salvage procedures. This article aims to present the authors' orthoplastic approach for the functional reconstruction of composite secondary Achilles tendon defects. Seven patients with chronic open-wound and large Achilles tendon defects (Kuwada type IV) underwent one-stage reconstruction between October of 2018 and October of 2020. The size of the average soft-tissue defect was 126.2 cm 2 (range, 86.1 to 175.9 cm 2 ), with a tendon gap of 8.2 cm (range, 7.1 to 10.3 cm). A combined team of orthoplastic surgeons performed the reconstructive procedure, using a turndown gastrocnemius fascial flap and a fascia lata autograft for the tendon reconstruction and a free fasciocutaneous anterolateral thigh flap for soft-tissue coverage (graft and flap). Subjective evaluation and quality-of-life measures were obtained preoperatively and 12 months postoperatively using the American Orthopedic Foot and Ankle Score and 36-Item Short-Form Health Survey questionnaire. Mean follow-up was 18.3 months (range, 12 to 24 months). The flap survival rate was 100%. Overall range of motion of the reconstructed side was 87% of the unaffected side (54 degrees versus 62 degrees). The American Orthopedic Foot and Ankle Score and 36-Item Short-Form Health Survey scores of all patients improved significantly ( P < 0.005) at 12 months of follow-up. A microsurgical approach combined with orthopedic techniques can solve complex cases of Achilles tendon secondary rupture, providing a reconstructed tendon that achieves satisfactory anatomic shape and function. Therapeutic, IV.

IPSC-derived tenocytes seeded on microgrooved 3D printed scaffolds for Achilles tendon regeneration.

Tendons and ligaments have a poor innate healing capacity, yet account for 50% of musculoskeletal injuries in the United States. Full structure and function restoration postinjury remains an unmet clinical need. This study aimed to assess the application of novel three dimensional(3D) printed scaffolds and induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) overexpressing the transcription factor Scleraxis (SCX, iMSCSCX+ ) as a new strategy for tendon defect repair. The polycaprolactone (PCL) scaffolds were fabricated by extrusion through a patterned nozzle or conventional round nozzle. Scaffolds were seeded with iMSCSCX+ and outcomes were assessed in vitro via gene expression analysis and immunofluorescence. In vivo, rat Achilles tendon defects were repaired with iMSCSCX+ -seeded microgrooved scaffolds, microgrooved scaffolds only, or suture only and assessed via gait, gene expression, biomechanical testing, histology, and immunofluorescence.iMSCSCX+ -seeded on microgrooved scaffolds showed upregulation of tendon markers and increased organization and linearity of cells compared to non-patterned scaffolds in vitro. In vivo gait analysis showed improvement in the Scaffold + iMSCSCX+ -treated group compared to the controls. Tensile testing of the tendons demonstrated improved biomechanical properties of the Scaffold + iMSCSCX+ group compared with the controls. Histology and immunofluorescence demonstrated more regular tissue formation in the Scaffold + iMSCSCX+ group. This study demonstrates the potential of 3D-printed scaffolds with cell-instructive surface topography seeded with iMSCSCX+ as an approach to tendon defect repair. Further studies of cell-scaffold constructs can potentially revolutionize tendon reconstruction by advancing the application of 3D printing-based technologies toward patient-specific therapies that improve healing and functional outcomes at both the cellular and tissue level.