Repair of articular cartilage defects in minipigs by microfracture surgery and BMSCs transplantation

Objective:To investigate the feasibility of minimal invasive repair of cartilage defect by arthroscope-aided microfracture surgery and autologous transplantation of mesenchymal stem cells. Methods: Bone marrow of minipigs was taken out and the bone marrow derived mesenchymal stem cells (BMSCs) were isolated and cultured to passage 3. Then 6 minipigs were randomly divided into 2 groups with 6 knees in each group. After the articular cartilage defect was induced in each knee, the left defect received microfracture surgery and was injected with 2.5 ml BMSCs cells at a concentration of 3×107 cells/ml into the articular cavity; while right knee got single microfracture or served as blank control group. The animals were killed at 8 or 16 weeks, and the repair tissue was histologically and immunohistochemically examined for the presence of type Ⅱ collagen and glycosaminoglycans (GAGs) at 8 and 16 weeks. Results: Eight weeks after the surgery, the overlying articular surface of the cartilage defect showed normal color and integrated to adjacent cartilage. And 16 weeks after surgery, hyaline cartilage was observed at the repairing tissues and immunostaining indicated the diffuse presence of this type Ⅱ collagen and GAGs throughout the repair cartilage in the treated defects. Single microfracture group had the repairing of fibrocartilage, while during the treatment, the defects of blank group were covered with fewer fiber tissues, and no blood capillary growth or any immunological rejection was observed. Conclusion: Microfracture technique and BMSCs transplantation to repair cartilage defect is characterized with minimal invasion and easy operation, and it will greatly promote the regeneration repair of articular cartilage defect.

Fabrication and Evaluation of Porous Keratin/chitosan(KCS) Scaffolds for Effectively Accelerating Wound Healing

Objective To develop a dressing with desired antibacterial activity, good water maintaining ability and mechanical properties for wound healing and skin regeneration. Methods The chitosan with different concentrations were added in keratin solution to form porous keratin/chitosan（KCS） scaffolds. The morphological characteristics, chemical composition, wettability, porosity, swelling ratio and degradation of the scaffolds were evaluated. The antibacterial activity was tested by using S. aureus and E. coli suspension for 2 h. And L929 fibroblast cells culture was used to evaluate the cytotoxicity of the KCS scaffolds. Results The adding of chitosan could increase the hydrophobicity, decrease porosity, swelling ratio and degradation rate of the KCS porous scaffolds. Mechanical properties of KCS scaffolds could be enhanced and well adjusted by chitosan. KCS scaffolds could obviously decrease bacteria number. The proliferation of fibroblast cells in porous KCS patch increased firstly and then decreased with the increase of chitosan concentration. It was appropriate to add 400 μg/m L chitosan to form porous KCS scaffold for achieving best cell attachment and proliferation compared with other samples. Conclusion The porous KCS scaffold may be used as implanted scaffold materials for promoting wound healing and skin regeneration.

Arthroscopically assisted treatment for Schatzker type Ⅰ-Ⅴ tibial plateau fractures

Objective： To report the clinical outcome of arthroscopically assisted treatment for tibial plateau fractures. Methods： A total of 39 patients with tibial plateau fractures were treated by arthroscopic fixation from February 2002 to December 2005, including 11 patients with bony avulsion of the anterior cruciate ligament and 19 with meniscal injury. There were 4 cases of type Ⅰ fracture, 12 type Ⅱ, 9 type Ⅲ, 12 type Ⅳ and 2 type Ⅴ according to Schatzker criteria. Firstly, the combined injuries were treated. Then the plateau fractures with the displacement over 3 mm or more were reduced and fixed. Finally, the internal fixation was observed by X-ray equipment. Postoperative management was early motion and delayed weight bearing. Results： All the fractures healed in 3 or 4 months. All patients were followed up for 1 to 5 years after operation.No case had severe complications, such as poor wound healing, infection, osteofascial compartment syndrome and osteoarthfitis. According to the Rasmussen scoring system, 36 cases obtained excellent or good results and the other 3 cases had moderate clinical results. The average score was 26 ± 3. Conclusions： As an adjuvant treatment of intraarticular fractures such as tibial plateau fracture, arthroscopy has many advantages. It can treat associated intraarticular soft tissue components, visualize the chondral surface reduction, lavage the hematoma and smaller loose fragments, decrease soft tissue dissection, reduce the risk of scarring and promote rapid recovery.

Hemi-arthroplasty performed in a 109-year-old patient with intertrochanteric fracture： A case report

The mortality of conservative treatment and the risk resulting from operation for elderly patients with femoral intertrochanteric fractures are high. Safety in the perioperative period and quicker recovery should be placed at the top priority for elderly patients with hip fractures. We reported a case of 109- year-old female patient with intertrochanteric fracture who has undergone the hemiarthroplasty in our center recently. With sciatic nerve and lateral cutaneous nerve block anesthesia, she was offered the artificial femoral head replacement in the lumbar plexus block after sufficient preoperative preparation. The surgery went well with minimally invasive cut, and the patient＇s recovery was satisfactory.

Properties of deproteinized bone for reparation of big segmental defect in long bone

Objective： To explore suitable scaffold material for big segmental long bone defect by studying the properties of the prepared deproteinized bone. Methods： Cancellated bone were made as 30 mm × 3 mm × 3 mm bone blocks from inferior extremity of pig femur along bone trabecula. The deproteinized bone was prepared with an improved method. Their morphological features, components, cell compatibility, mechanical and immunological properties were investigated respectively. Results： Deproteinized bone maintained natural re-ticular pore system. The main organic material is collagen I and inorganic composition is hydroxyapatite. It has good mechanical properties, cell adhesion rate and histocompatibility. Conlusion： This deproteinized bone can be applicable as scaffold for reparation of big segmental defect in long bone.

Preparation and characterization of methacrylated gelatin/bacterial cellulose composite hydrogels for cartilage tissue engineering

Methacrylated gelatin(GelMA)/bacterial cellulose(BC)composite hydrogels have been successfully prepared by immersing BC particles in GelMA solution followed by photo-crosslinking.The morphology of GelMA/BC hydrogel was examined by scanning electron microscopy and compared with pure GelMA.The hydrogels had very well interconnected porous network structure,and the pore size decreased from 200 to 10 mm with the increase of BC content.The composite hydrogels were also characterized by swelling experiment,X-ray diffraction,thermogravimetric analysis,rheology experiment and compressive test.The composite hydrogels showed significantly improved mechanical properties compared with pure GelMA.In addition,the biocompatility of composite hydrogels were preliminarily evaluated using human articular chondrocytes.The cells encapsulated within the composite hydrogels for 7 days proliferated and maintained the chondrocytic phenotype.Thus,the GelMA/BC composite hydrogels might be useful for cartilage tissue engineering.

Study on the correlation between early three-dimensional gait analysis and clinical efficacy after robot-assisted total knee arthroplasty

Purpose:Robot-assisted technology is a forefront of surgical innovation that improves the accuracy of total knee arthroplasty (TKA).But whether the accuracy of surgery can improve the clinical efficacy still needs further research.The purpose of this study is to perform three-dimensional (3D) analysis in the early postoperative period of patients who received robot-assisted total knee arthroplasty (RATKA),and to study the trend of changes in gait parameters after RATKA and the correlation with the early clinical efficacy.Methods:Patients who received RATKA in the Center of Joint Surgery,the First Hospital Affiliated to Army Military Medical University from October 2020 to January 2021 were included.The imaging parameters,i.e.,hip-knee-ankle angle,lateral distal femoral angle,medial proximal tibial angle,posterior condylar angle were measured 3 months post-TKA.The 3D gait analysis and clinical efficacy by Western Ontario Mac Master University Index (WOMAC) score were performed pre-TKA,3 and 6 months post-TKA.The differences in spatiotemporal parameters of gait,kinetic parameters,and kinematic parameters of the operated limb and the contralateral limb were compared.The correlation between gait parameters and WOMAC scores was analyzed.Paired samplet-test and Wilcoxon rank-sum test were used to analyze the difference between groups,and Spearman correlation coefficient was used to analyze the correlation.Results:There were 31 patients included in this study,and the imaging indexes showed that all of them returned to normal post-TKA.The WOMAC score at 3 months post-TKA was significantly lower than that pre-TKA,and there was no significant difference between at 3 and 6 months.The 3D gait analysis results showed that the double support time of the operated limb reduced at 3 and 6 months (allp < 0.05),the maximum extension and maximum external rotation of the knee joint increased at stance phase,and the maximum flexion angle,the range of motion and the maximum external rotation increased at swing phase.Compared with the preoperative data,there were significant improvements (allp < 0.05).Compared with the contralateral knee joint,the maximum external rotation of the knee joint at swing phase was smaller than that of the contralateral side,and the maximum flexion and extension moment was greater than that of the contralateral knee.The maximum external rotation moment of the joint was greater than that of the contralateral knee joint (p < 0.05).There was a negative correlation between the single support time pre-TKA and the WOMAC score at 3 months (p = 0.017),and the single support time at 3 months was negatively correlated with the WOMAC score at 6 months (p = 0.043).The cadence at 6 months was negatively correlated with the WOMAC score at 6 months (p = 0.031).The maximum knee extension at stance phase at 6 months was negatively correlated with the WOMAC score at 6 month (p = 0.048).The maximum external rotation at stance phase at 6 months was negatively correlated with the WOMAC score at 6 months (p = 0.024).Conclusion:The 3D gait analysis of RATKA patients is more sensitive than WOMAC score in evaluating the clinical efficacy.Trend of changes in gait parameters shows that the knee joint support,flexion and extension function,range of motion,external rotation and varus deformity moment of the patient were significantly improved at 3 months after surgery,and continued to 6 months after surgery.Compared with the contralateral knee,the gait parameters of the operated limb still has significant gaps in functionality,such as the external rotation and flexion and extension.The single support time,cadence,knee extension,and knee external rotation of the operated limb have a greater correlation with the postoperative WOMAC score.Postoperative rehabilitation exercises should be emphasized,which is of great value for improving the early efficacy of RATKA.

Arthroscopic treatment of ankle impingement syndrome

Arthroscopic treatment of ankle impingement syndrome(AIS)is a minimally invasive surgical procedure used to address symptoms caused by impingement in the ankle joint.This syndrome occurs when there is abnormal contact between certain bones or soft tissues in the ankle,leading to pain,swelling,or limited range of motion.Traditionally,open surgery was the standard approach for treating AIS.However,with advancements in technology and surgical techniques,arthroscopic treatment has become a preferred method for many patients and surgeons.With improved visualization and precise treatment of the arthroscopy,patients can experience reduced pain and improved functionality,allowing them to return to their daily activities sooner.In this paper,we reviewed the application and clinical efficacy the of arthroscopic approach for treating AIS,hoping to provide a reference for its future promotion.

Study of biological safety of scaffold material with heterologous deproteinized bone

To evaluate the biological safety of manufactured heterologous deproteinized bone and to provide an experimental basis for clinical applications. Methods ： Deproteinized bone （ 10 mm） and leaching liquor were made from pig ribs with a series of physical and chemical methods, then were evaluated through acute and subacute toxicity test, hemolysis test, pyrogen test, intracutaneous test, intramuscular implantation test and cytotoxity test. Results ： No obvious toxicity, hemolysis, pyrogenic characteristics, skin irritation, inflammatory reaction after intramusclar implantation and cytotoxity were observed. Conclusions： The heterologous deproteinized bone has good biological safety and meets all the demands of scaffold material for tissue engineering.

Exosomes:key players in cancer and potential therapeutic strategy

Exosomes are extracellular vesicles secreted by most eukaryotic cells and participate in intercellular communication.The components of exosomes,including proteins,DNA,mRNA,microRNA,long noncoding RNA,circular RNA,etc.,which play a crucial role in regulating tumor growth,metastasis,and angiogenesis in the process of cancer development,and can be used as a prognostic marker and/or grading basis for tumor patients.Hereby,we mainly summarized as followed:the role of exosome contents in cancer,focusing on proteins and noncoding RNA;the interaction between exosomes and tumor microenvironment;the mechanisms that epithelial-mesenchymal transition,invasion and migration of tumor affected by exosomes;and tumor suppression strategies based on exosomes.Finally,the application potential of exosomes in clinical tumor diagnosis and therapy is prospected,which providing theoretical supports for using exosomes to serve precise tumor treatment in the clinic.

A follow-up study of arthroscopic combined reconstruction of anterior and posterior cruciate ligaments with allograft patellar tendon

Objective:To evaluate the therapeutic effect of combined reconstruction of anterior cruciate ligament (ACL)and posterior cruciate ligament(PCL) simultaneously by using allograft patellar tendon under arthroscopy. Methods:From May 2003 to November 2005,10 cases of ruptured ACL and PCL were fixated with compressed screws and reconstructed under arthroscopy with allograft patellar tendon simultaneously.The clinical results were evaluated according to IKDC,Lysholm,and Tegner clinical rating scales. Results:All patients were followed up for 12-30 months(mean:18 months).At the last follow-up,there was no knee extension limitation and knee flexion was between 120°and 135°,with an average of 128.38°.The Lysholm score of the 10 cases was 66.5±5.6 before operation and 89.8±3.4 at last follow up.The difference was statistically significant(P<0.01).The average Tegner activity score decreased from 6.9±1.7(range.4-9)before injury to 5.5±1.6(rang:2-9)at the follow-up (P=0.53).At the end of follow-up,IKDC score was graded as A in 4 cases(40.0%),B in 5(50.0%),and C in 1(10.0%).Of the 10 patients,8 returned to the same sports level as before injury and 2 were under the level. Conclusion:Arthroscopic combined reconstruction of ACL and PCL with allograft patellar tendon has the advantages of minimal trauma in surgery and reliable satisfactory outcome.

Biomechanical researches on tissue engineering bone constructed by deproteinated bone

Objective： To study biomechanical changes of newly formed bones 24 weeks after repairing large defects of long bones of goats using heterogeneous deproteinated bone （DPB） prepared by modified methods as an engineering scaffold. Methods： According to a fully randomized design, 18 goats were evenly divided into three groups： normal bone control group （Group A）, autologous bone group （Group B） and experimental group （Group C）. Each goat in Groups B and C were subjected to the periosteum and bone defect at middle-lower part of the right tibia （20% of the whole tibia in length）, followed by autologous bone or DPB plus autolognus MSCs ＋ rhBMP2 implantation, respectively and semi- ring slot fixation; while goats in Group A did not perform osteotomy. At 24 weeks after surgery, biomechanical tests were carried out on the tibias. Results： At 24 weeks after surgery, the results of anticompression test on tibias in three groups were recorded by a functional recorder presented as linear pressure-deformation curve. The shapes of the curves and their change tendency were similar among three groups. The ultimate pressure values were 10.74 MPa±1.23 MPa, 10. 11 MPa±1.35 MPa and 10.22 MPa±1.32 MPa and fracture compression rates were 26.82%±0.87%, 27.17%±0.75% and 28.22%±1.12% in Groups A, B and C, respectively. Comparisons of anti-compression ultimate pressures and fracture compression rates among three groups demonstrated no significant difference （PAB=0.415, PBC=0.494）. Three-point antibend test on tibias was recorded as load-deformation curves, and the shapes of the curves and their change tendency were similar among three groups. The ultimate pressure values of the anti-bend test were 481.52 N±12.45 N, 478.34 N±14.68 N and 475.62 N±13.41 N and the fracture bend rates were 2.62 mm±0.12 mm, 2.61 mm±0.15 mm and 2.81 mm±0.13 mm in Groups A, B and C, respectively. There was no significant difference between groups （PAB=0.7, PBc=0.448）. The ultimate anti-torsion torque values were 6.55 N.mi-0.25 N.m, 6.34 N＇m^0.18 N＇m and 6.42 N＇m^0.21 N＇m and fracture torsion rates were 29.51°±1.64°, 28.88±1.46° and 28.81°±1.33° in Groups A, B and C, respectively. There was no significant difference between groups （PAB=0.123, PBc=0.346）. Conclusions： The biomechanical characteristics of newly formed bones from heterogeneous DPB for repairing large segmental long bone defect are comparable to those of normal bones and autologous bones. DPB has the potential for clinical usage as bone graft material.

Immunological study on the transplantation of an improved deproteinized heterogeneous bone scaffold material in tissue engineering

Objective： To observe the immune response after the transplantation of a deproteinized heterogeneous bone scaffold and provides the theoretic reference for clinical practice. Methods： The fresh pig bone and deproteinized bone were transplanted respectively to establish BABL/C thigh muscle pouches model of male mice and take the samples for detection at 1, 2, 4, 6 weeks after operation. Lymphocyte stimulation index, subset analysis, serum specific antibody IgG, cytokine detection and topographic histologic reaction after implantation were investigated. Results： After the transplantation of deproteinized bone, lymphocyte stimulation index, CD4^＋ and CD8^＋ T-lymphocyte subsets, serum specific antibody IgG and cytokines in deproteinized bone group were significantly lower than those in fresh pig bone group at each time point （P〈0.05）. The histological examination found that in fresh bone group at each time point, a large quantity of inflammatory cells infiltrated in the surrounding of bone graft, and they were mainly lymphocytes, including macrophages and monocytes. In deproteinized bone group, there were few inflammatory cells infiltration around bone graft one week after operation. The lymphocytes were decreased as time went by. At 6 weeks, fibroblasts and fibrous tissue grew into the graft, and osteoclasts and osteoprogenitor cells appeared on the verge. Conclusions： The established heterogeneous deproteinized bone has low immunogenicity and is a potentially ideal scaffold material for bone tissue engineering.

Preparation and physicochemical properties of scaffold materials of heterogeneous deproteinized bone

Objective ： To prepare and observe the physicochemical properties of scaffold materials of heterogeneous deproteinized tissue-engineered bone. Methods： Deproteinized bone was made through a series of physicochemical treatments in pig ribs and analyzed with histological observation, scanning electron microscopy, infrared spectrum, X-ray diffraction and energy dispersive analysis, Kjeidahl determination and mechanics analysis. Results： Interstitial collagen fiber was positive and mucin was negative in deproteinized bone, but, both were positive in fresh bone. Deproteinized bone maintained natural pore network. Its pore size was 472.51μm ± 7.02μm and the porosity was 78.15 % ± 6.45 %. The results of infrared spectrum showed that collagen was present in deproteinized bone. Both fresh and deproteinized bone had curve of hydroxyapatite. The Ca/P ratios were 1.71 ± 0. 95 and 1.68 ± 0. 76 （ P 〉 0. 05 ）, and the protein contents were26.6% ± 2.23% and 19.1% ± 2.14% （P 〈 0.05） in fresh and deproteinized bone, respectively. There was no significant difference of destruction load under compression and maximal destruction load between fresh and deproteinized bone （P 〉 0. 05）. The elastic modulus was higher in deproteinized bone than that in fresh bone （P 〈 0.05）. Conclusions ： Physicochemical properties and mechanic strength of deproteiulzed tissue-engineered bone meet the demands of ideal scaffold materials. But, its immunogenicity should be observed through further experiments for its clinical applications.

Tropoelastin improves adhesion and migration of intra-articular injected infrapatellar fat pad MSCs and reduces osteoarthritis progression

Intra-articular injection of mesenchymal stem cells(MSCs)is a promising strategy for osteoarthritis(OA)treatment.However,more and more studies reveal that the injected MSCs have poor adhesion,migration,and survival in the joint cavity.A recent study shows that tropoelastin(TE)regulates adhesion,proliferation and phenotypic maintenance of MSCs as a soluble additive,indicating that TE could promote MSCs-homing in regenerative medicine.In this study,we used TE as injection medium,and compared it with classic media in MSCs intra-articular injection such as normal saline(NS),hyaluronic acid(HA),and platelet-rich plasma(PRP).We found that TE could effectively improve adhesion,migration,chondrogenic differentiation of infrapatellar fat pad MSCs(IPFP-MSCs)and enhance matrix synthesis of osteoarthritic chondrocytes(OACs)in indirect-coculture system.Moreover,TE could significantly enhance IPFP-MSCs adhesion via activation of integrin β1,ERK1/2 and vinculin(VCL)in vitro.In addition,intra-articular injection of TE-IPFP MSCs suspension resulted in a short-term increase in survival rate of IPFP-MSCs and better histology scores of rat joint tissues.Inhibition of integrin β1 or ERK1/2 attenuated the protective effect of TE-IPFP MSCs suspension in vivo.In conclusion,TE promotes performance of IPFP-MSCs and protects knee cartilage from damage in OA through enhancement of cell adhesion and activation of integrin β1/ERK/VCL pathway.Our findings may provide new insights in MSCs intra-articular injection for OA treatment.

Painful locking of the knee due to bucket handle tear of mediopatellar plica

A case of swelling and anterior painful knee due to tear of mediopateUar plica is reported. The patient also felt clunk of the patellofemoral joint and knee locking. Under arthroscopic examination, a thick and fibrous plica was found medial to patellar, and a bucket tear along the plica from medial patellar retinaculum to infrapatellar fat pad. Polarized microscopic examination showed collagen fiber fragment and loss of light reflecting property. Neuroimmunohistology suggested up-regulation of synovial plica innervation in the area around the crack. This may be related to the pain. The bucket tear of mediopatellar plicacaused pain and lock of knee are more common than previously reported.

Cellular compatibility of improved scaffold material with deproteinized heterogeneous bone

Objective:To study cellular compatibility of improved scaffold material with deproteinized heterogeneous bone and provide experimental basis on choosing the scaffold material in bone tissue engineering. Methods:Bone marrow stromal cells(BMSC)were co-cultured with heterogeneous deproteinized bone in vitro. The contrast phase microscope,scanning electron microscope,MTT assay,flow cytometry were performed and the BGP content and ALP activities were detected in order to observe the cell growth,adhesion in the material, cell cycle and cell viability. Results:The scaffold material of deproteinized heterogeneous bone had no inhibitory effect on cellular proliferation,differentiation and secretion function of BMSCs. Conclusions:The established heterogeneous deproteinized bone has good biocompatibility with BMSCs and is a potentially ideal scaffold material for bone tissue engineering.

Acute arterial occlusion in the midpiece of femoral artery following total knee arthroplasty： Report of one case

Acute arterial occlusion is a rare complication following total knee arthroplasty （TKA）. The incidence as reported previously is from 0.03% to 0.17%; however, the sequelae can be disastrous because of its potential threat to limb loss. We report a case of acute arterial occlusion in the midpiece of femoral artery following TKA occurred 40 rain postoperatively. The occlusion site existed at the midpiece of femoral artery is uncommon. Arterial circulation of the lower limb could not be restored by the thrombolysis and thrombectomy treatments performed within 11 h after TKA. In the end, amputation had to be carried out. In the treatment of acute arterial occlusion following TKA with a tourniquet, it is important to fully consider that arteriosclerosis may induce atheromatous plaque disruption, which might be the reason for acute arterial occlusion.

Laser Powder Bed Fusion-built Ti6Al4V Bone Scaffolds Composed of Sheet and Strut-based Porous Structures: Morphology, Mechanical Properties, and Biocompatibility

Laser powder bed fusion(L-PBF)-built triply periodic minimal surface(TPMS)structures are designed by implicit functions and are endowed with superior characteristics,such as adjustable mechanical properties and light-weight features for bone repairing;thus,they are considered as potential candidates for bone scaffolds.Unfortunately,previous studies have mainly focused on different TPMS structures.The fundamental understanding of the differences between strut and sheet-based structures remains exclusive,where both were designed by one formula.This consequently hinders their practical applications.Herein,we compared the morphology,mechanical properties,and biocompatibility of sheet and strut-based structures.In particular,the different properties and in vivo bone repair effects of the two structures are uncovered.First,the morphology characteristics demonstrate that the manufacturing errors of sheet-based structures with diverse porosities are comparable,and semi-melting powders as well as the ball phenomenon are observed;in comparison,strut-based samples exhibit cracks and thickness shrinking.Second,the mechanical properties indicate that the sheet-based structures have a greater elastic modulus,energy absorption,and better repeatability compared to strut-based structures.Furthermore,layer-by-layer fracturing and diagonal shear failure modes are observed in strut-based and sheet-based structures,respectively.The in vivo experiment demonstrates enhanced bone tissues in the strut-based scaffold.This study significantly enriches our understanding of TPMS structures and provides significant insights in the design of bone scaffolds under various bone damaging conditions.

Robotic arm-assisted arthroplasty:The latest developments

Joint arthroplasty is an effective method for treating end-stage joint lesions and damages.Robotic arm-assisted arthroplasty,a rapidly developing technology that combines navigation technology,minimally invasive technology,and precise control technology of the robotic arm,can achieve accurate preoperative planning,optimal selection of implants,minimally invasive surgery,precise osteotomy,and accurate placement of the artificial joint.It has the characteristics of high accuracy and stability,and thus is more and more widely used in the field of joint surgery.In this paper,we systematically reviewed the application and clinical efficacy of robotic arm-assisted technology in hip and knee arthroplasty to provide reference for its future promotion.