Autologous Cartilage Research Articles

Vertical Strut Ossiculoplasty: A Versatile Alternate to Conventional Techniques-A Randomized study.

Various ossicular reconstruction materials and techniques have been described in literature using autologous ossicle, cortical bone, autologous cartilage, synthetic materials and implants like total/partial ossicular replacement prosthesis (TORP/PORP) etc., but it has always been a topic of controversy in terms of the efficacy, longevity and complications of the material or method used. This is a prospective, interventional, comparative, double-blind randomized control study which was done at a tertiary care center to compare outcomes of conventional and carved conchal cartilage (vertical strut) type III Tympanoplasty in terms of graft uptake and hearing gain. A total number of 52 cases were enrolled, randomized and allocated to 2 groups (26 each) i.e. group A (conventional type III) and group B (vertical strut technique). Graft uptake was seen in 25 (96.16%) patients in group B while it was observed in 23 (88.5%) cases in group A. Hearing gains were also better in group B. This study suggests that Vertical Strut technique can be studied further as it gives better gains in Air Conduction threshold and A-B Gap along with graft uptake as it provides better middle ear space and ossicular / tympanic membrane interface resulting in better hearing.

Is Irradiated Homologous Costal Cartilage Reliable? A Meta-Analysis of Complication Rates in Rhinoplasty.

Background: Irradiated homologous costal cartilage (IHCC) may be a convenient, cost-effective and efficient alternative source of graft material in rhinoplasty; however, a systematic review and meta-analysis on this topic have not been previously performed. Objectives: We sought to summarize and pool data on complications associated with the use of IHCC grafting in rhinoplasty. Methods: A systematic review and meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. We conducted PubMed, Cochrane, Embase, Web of Science database searches, and screened articles using specific inclusion and exclusion criteria. Pooled complication rates were analyzed using a random-effects model. Results: Of the 13 studies that met criteria for systematic review, 11 studies involving 1017 patients, with 1956 IHCC grafts used, were included in the meta-analysis. Mean follow-up across all studies was 47 months. Overall, the pooled complication rates were 1.14% (95% CI: 0.3%-2.0%) for resorption, 0.5% (95% CI: 0.1%-0.9%) for warping, 1.2% (95% CI: 0.3%-2.1%) for infection, 1.0% (95% CI: 0.1%-2.0%) for mobility, and 0.8% (95% CI: 0.1%-1.6%) for graft removal or replacement. No allergic reactions or systemic disease associated with IHCC use were reported in any of the studies. Conclusions: The overall complications associated with IHCC use in rhinoplasty were very low. Costal cartilage allografts are an area of renewed interest that may represent an alternative to autologous costal cartilage grafting in rhinoplasty due to their low complication rates, convenience, cost-effectiveness, and elimination of donor-site complications.

Clinical study of the autologous concha cartilage transplantation to repair the auricle defect

Objective:To investigate the curative effect of the auricular defect repaired by the autologous concha cartilage. Methods:Seven cases with the auricular defect were repaired using the autologeous concha cartilage which combined with the retroauricular flap or retroauricular fascia with skin graftin. Results:Total 7 patients were followed up for 6 months after the surgery. The shape and size of the repaired ears were similar to the healthy ears. The teansplanted cartilages were not absorbed or deformed. Conclusion:This method is harmless and simple,which has reliable and satisfactory effects on auricle defect. We can operate under local anethesia and avoid cutting the rib cartilage.

Research progress of autogenous cartilage scaffold carving method in rhinoplasty

To summarize the research progress of autogenous cartilage scaffold carving method in rhinoplasty. The relevant literature about the autogenous cartilage scaffold carving methods in rhinoplasty in resent years at home and abroad was reviewed, and the carving skills, shape, and application scope of different parts of nasal scaffolds were summarized and analyzed. Willow-leaf shape is still the main method of cartilage scaffold in the back of the nose. However, in nasal reconstruction, it can be carved into an L-shaped scaffold with the nasal columella scaffold through mortise and tenon structure. And it can also crush the autologous cartilage and wrap it with the autologous fascia tissue to form a new nasal dorsal scaffold. The nasal tip scaffold is improved by changing the shape of traditional nasal tip cartilage cap and wrapping with fascia tissue; the nasal alar scaffold has M-shape, q-shape, carving methods; the nasal columella and nasal septum are mostly used "2+2" combined fixed scaffold. The cartilage scaffolds of lateral nose and nasal base are mainly carved in the shape of "" and crescent. As a rhinoplasty scaffold, there are various carving methods for autogenous cartilage. With the innovation of surgical technique and the improvement of sculpting technique, the effect of autologous cartilage graft in rhinoplasty is getting better and better; meanwhile, tissue engineered cartilage is being applied in rhinoplasty.

Scaffold-Free Engineering of Human Cartilage Implants.

ObjectiveDespite new strategies in tissue engineering, cartilage repair remains a major challenge. Our aim is to treat patients with focal lesions of articular cartilage with autologous hyaline cartilage implants using a scaffold-free approach. In this article, we describe experiments to optimize production of scaffold-free cartilage discs.DesignArticular chondrocytes were expanded in vitro, seeded in transwell inserts and redifferentiated using established chondrogenic components. Experimental variables included testing 2 different expansion media, adding bone morphogenetic protein 2 (BMP2), insulin-like growth factor 1 (IGF1), growth/differentiation factor 5 (GDF5), or fibroblast growth factor 18 (FGF18) to the differentiation medium and allowing the disc to float freely in large wells. Cartilage discs were analyzed by weight and thickness, real-time RT-qPCR (reverse transcriptase qualitative polymerase chain reaction), fluorescence immunostaining, transmission electron microscopy, second harmonic generation imaging, and measurement of Young’s modulus.ResultsAddition of BMP2 to the chondrogenic differentiation medium (CDM) was essential for stable disc formation, while IGF1, GDF5, and FGF18 were redundant. Allowing discs to float freely in CDM on a moving platform increased disc thickness compared with discs kept continuously in transwell inserts. Discs cultured for 6 weeks reached a thickness of almost 2 mm and Young’s modulus of >200 kPa. There was abundant type II collagen. Collagen fibrils were 25 nm thick, with a tendency to be organized perpendicular to the disc surface.ConclusionScaffold-free engineering using BMP2 and providing free movement in CDM produced firm, elastic cartilage discs with abundant type II collagen. This approach may potentially be used in clinical trials.

The Silicone Turkish Delight for Dorsal Augmentation in Rhinoplasty.

Rhinoplasties are the most challenging facial aesthetic procedures with the majority of the cases requiring dorsal augmentation either in the form of autogenous or alloplastic materials. Although autogenous grafts are the gold standard, these grafts have their innate issues such as donor site morbidity, occasional displacement, resorption, tendency to warp or develop sharp edges over time with increased perceptibility and clinical visibility of the graft with time. These issues were addressed by Erol in 2000 who advocated the use of finely diced autologous cartilage wrapped in a monolayer of surgical and termed it Turkish delight. This technique has been extensively modified by surgeons across the world with an attempt to forgo the use of autogenous grafts preventing donor site morbidity and replacing it with alloplastic materials. Silicon's inert nature, resorption resistance, absence of a secondary surgical site and economical value make it a widely utilized allograft augmentation option in Asian countries. The authors hereby present a modification of the original Turkish delight technique by utilizing diced silicone pieces amalgamated with 1 to 2 ml of autologous blood and wrapped in monolayer of surgicel (oxidized cellulose). The technique produced clinically stable results in 27 patients who were followed up for a period of 24 to 60 months (average 30 months). Improved pliability, negated risk of graft extrusion with no donor site morbidity are the key advantages of this technique over conventional autologous grafts and silicon block augmentation techniques. These results point towards the viability of the technique for performing dorsal augmentation in rhinoplasty.

Effect of Expanded Polytetrafluoroethylene Combined with Autologous Ear Cartilage in Nasal Plastic Surgery

Objective: To explore the effect of combined application of expanded polytetrafluoroethylene and autologous ear cartilage in nasal plastic surgery. Methods: 76 cases of nasal plastic surgery patients in our hospital from September 2019 to September 2020 were selected as the research objects and divided into experimental group (38 cases, treated with expanded polytetrafluoroethylene + autologous ear cartilage surgery) and control group (38 cases, treated with autologous ear cartilage surgery). The treatment effect, appearance score and complications were compared. Results: The total effective rate of the experimental group (97.37%, 37 / 38) was higher than that of the control group (78.95%, 30 / 38), P< 0.05; After treatment, the appearance score of the experimental group was (8.97 ± 0.37), which was significantly higher than that of the control group (P< 0.05); The total incidence of complications in the experimental group (5.26%, 2 / 38) was significantly lower than that in the control group (21.05%, 8 / 38), P< 0.05. Conclusion: In the process of nasal plastic surgery, the combined application of autologous ear cartilage surgery and expanded polytetrafluoroethylene has obvious effect, improves the appearance of patients, and has less postoperative complications, which is worthy of promotion.

Nipple Engineering: Maintaining Nipple Geometry with Externally Scaffolded Processed Autologous Costal Cartilage

Nipple reconstruction is the essential last step of breast reconstruction after total mastectomy, resulting in improved general and aesthetic satisfaction. However, most techniques are limited by secondary scar contracture and loss of neo-nipple projection leading to patient dissatisfaction. Approximately, 16,000 patients undergo autologous flap breast reconstruction annually, during which the excised costal cartilage (CC) is discarded. We propose utilizing processed CC placed within biocompatible 3D-printed external scaffolds to generate tissue cylinders that mimic the shape, size and biomechanical properties of native human nipple tissue while mitigating contracture and projection loss. External scaffolds were designed and then 3D-printed using polylactic acid (PLA). Patient-derived CC was processed by mincing or zesting, then packed into the scaffolds, implantedinto nude rats and explanted after3 months for volumetric, histologic and biomechanical analyses. Similar analyses were performed on native human nipple tissue and unprocessed CC. After 3 monthsin vivo,gross analysis demonstrated significantly greater preservation of contour, projection and volume of the scaffolded nipples. Mechanical analysis demonstrated that processing of the cartilage resulted in implant equilibrium modulus values closer to that of the human nipple. Histologic analysis showed the presence of healthy and viable cartilage after 3 months in vivo, invested with fibrovascular tissue. Autologous CC can be processed intraoperatively and placed within biocompatible external scaffolds to mimic the shape and biomechanical properties of the native human nipple. This allows for custom design and fabrication of individualizedengineeredautologousimplants tailored to patientdesire, without the loss of projection seen with traditional approaches.

Multiscale sterilizable 3D printed auricular templates to guide cartilaginous framework sizing and sculpture during autologous microtia reconstruction

SummaryMicrotia reconstruction using autologous costal cartilage can be one of the most challenging tasks in reconstructive surgery. An intraoperative guide using 2-dimentional drawing of the contralateral ear on an x-ray film remains the current standard of care. In this paper, we present the use of computer-aided design and desktop 3D printing to fabricate low cost, sterilizable auricular carving templates to serve as a peri-operative reference for microtia reconstruction. The design was made as a single component which incorporated the usual anatomic reference points of the ear based on Nagata technique as a Stereo-lithography file format (. STL) for 3D printing. The templates were created in sizes ranging from 55 mm to 70 mm with a 2 mm increment with an average production cost of 0.26 US dollars per material per template and about 4.5 US dollars for the whole set. Individual templates were then 3D-printed using a thermoplastic polyurethane (TPU 95A) semiflexible filament on a desktop fused deposition modeling, Ultimaker 2 + 3D printer. The produced template tolerated the sterilization process with no structural changes as compared to its pre-sterilization condition. In conclusion, we present cost-effective, sterilizable, multiscale auricular templates to guide the pre- and intra-operative carving of the cartilaginous framework during microtia reconstruction with more accuracy in a time efficient manner, thereby overcoming the drawbacks of using the traditional x-ray film. The templates are readily accessible and sharable for free through open-source software and can be directly 3D-printed using an affordable desktop 3D printer.

Sphenoidal Process of Septal Cartilage

Background: One of the main difficulties of revision rhinoplasty is the lack of sufficient septal cartilage. To overcome this problem, additional cartilage sources such as costal or conchal cartilages are widely used among surgeons. However, these methods can cause some complications. The sphenoidal process of septal cartilage (SPSC) is a unique part of septal cartilage located between the vomer bone and the perpendicular plate of the ethmoid bone and generally untouched during the surgery. As an autologous graft option, the SPSC may be an important cartilage source for revision rhinoplasty cases, especially in patients requiring minor surgical intervention. Methods: Between February 2019 and February 2020, a total of 50 patients who underwent paranasal computed tomography were enrolled in this retrospective study. The length, height, and surface area of the SPSC and surface area of total septal cartilage were calculated. Results: The mean total septal area was 886.2 mm2, ranging from 554.7 mm2 to 1277.5 mm2. The mean total SPSC area was 67.39 mm2. The mean length of SPSC was 12.8 mm in all populations. The highest sphenoidal process length measurement was 27.32 mm, and the lowest was 4.82. Mean sphenoidal process height values were similar in female and male groups (4.99 mm and 5.2 mm, respectively). Conclusion: The sphenoid process of septal cartilage may be an important autologous cartilage option for revision surgeries in terms of sufficient length and height dimensions.

Non-significant Effects of the Geometric Shape of Autologous Cartilage Grafts on Tissue Healing: An Animal Study

Non-significant Effects of the Geometric Shape of Autologous Cartilage Grafts on Tissue Healing: An Animal Study

Application of septal extension graft with autogenous septal cartilage and auricular cartilage in rhinoplasty

Objective: To explore the feasibility of reconstruction of nasal tip with septal cartilage and auricular cartilage. Methods: From September 2018 to October 2019, 17 patients (two males and fifteen females) with low noses underwent rhinoplasty under general anesthesia. The age of the patients ranged from 19 to 39, with an average of 27 years old. Among them, all the 17 cases were primary rhinoplasty. During the operation, autologous nasal septum cartilage was used as septal extension graft to extend the caudal septum, and the auricular cartilage was used to enhance the stability of the strut and to elevate the tip for adjusting the shape of nose by making into spreader graft, columellar strut graft, derotation graft and onlay graft. The nasal dorsum was filled with polytetrafluoroethylene. Digital scanning technology was used to evaluate the nasal structure before and after operation. SPSS 22 software was used to analyze the data with paired t-test. Results: The follow-up was from 6 to 12 months, with an avaerge of 7.6 months. Seventeen patients were satisfied with postoperative nasal morphology and height. There was no infection, prosthesis displacement, skin flap necrosis, no auricle deformation and other complications. Statistical software SPSS 22 performed paired t-test on the preoperative and postoperative data obtained by digital technology: postoperative nasal length and nasal tip protrusion increased compared with that before surgery, and it was statistically significant(length:(3.60±0.77)mm, tip protrusion:(3.61±0.64)mm, t value was -19.203 and -23.132 respectively, both P<0.001). The nasolabial Angle was smaller than that before surgery, and the data were statistically significant(3.40°±2.11°,t=6.635, P<0.001). Conclusion: The nasal tip and nasal septum extension complex constructed by autogenous nasal septal cartilage combined with auricular cartilage can increase the length of nasal tip, increase the height of nasal tip and reduce the angle of nasolabial angle.

In Vitro Effects of Bupivacaine on the Viability and Mechanics of Native and Engineered Cartilage Grafts

Background: Although the toxic effects of bupivacaine on chondrocyte monolayer culture have been well described, its cellular and mechanical effects on native and engineered articular cartilage remain unclear. For the repair of articular cartilage defects, fresh autologous and allogenic cartilage grafts are commonly used, and engineered cell-based therapies are emerging. The outcome of grafting therapies aimed at repairing damaged cartilage relies largely on maintaining proper viability and mechanical suitability of the donor tissues. Purpose: To investigate the in vitro effects of single bupivacaine exposure on the viability and mechanics of 2 cartilage graft types: native articular cartilage and engineered neocartilage. Study Design: Controlled laboratory study. Methods: Articular cartilage explants were harvested from the bovine stifle femoral condyles, and neocartilage constructs were engineered from bovine stifle chondrocytes using the self-assembling process, a scaffold-free approach to engineer cartilage tissue. Both explants and neocartilage were exposed to chondrogenic medium containing a clinically applicable bolus of 0.5%, 0.25%, or 0% (control) bupivacaine for 1 hour, followed by fresh medium wash and exchange. Cell viability and matrix content (collagen and glycosaminoglycan) were assessed at t = 24 hours after treatment, and compressive mechanical properties were assessed with creep indentation testing at t = 5 to 6 days after treatment. Results: Single bupivacaine exposure was chondrotoxic in both explants and neocartilage, with 0.5% bupivacaine causing a significant decrease in chondrocyte viability compared with the control condition (55.0% ± 13.4% vs 71.9% ± 13.5%; P < .001). Bupivacaine had no significant effect on matrix content for either tissue type. There was significant weakening of the mechanical properties in the neocartilage when treated with 0.5% bupivacaine compared with control, with decreased aggregate modulus (415.8 ± 155.1 vs 660.3 ± 145.8 kPa; P = .003), decreased shear modulus (143.2 ± 14.0 vs 266.5 ± 89.2 kPa; P = .002), and increased permeability (14.7 ± 8.1 vs 6.6 ± 1.7 × 10−15 m4/Ns; P = .009). Bupivacaine exposure did not have a significant effect on the mechanical properties of native cartilage explants. Conclusion: Single bupivacaine exposure resulted in significant chondrotoxicity in native explants and neocartilage and significant weakening of mechanical properties of neocartilage. The presence of abundant extracellular matrix does not appear to confer any additional resistance to the toxic effects of bupivacaine. Clinical Relevance: Clinicians should be judicious regarding the use of intra-articular bupivacaine in the setting of articular cartilage repair.

Experience With Autologous Nasal Septum Cartilage Combined With Conchal Cartilage in Nasal Tip Reconstruction.

There has been an increase in use of autologous costal cartilage for nasal tip shaping material. However, there are deficiencies in using this plastic material, such as a hard nasal tip, poor nasal tip elasticity and mobility postoperatively, and some nasal tip skin thinning that allows the shape of the cartilage grafts to be felt on the surface of the nasal tip skin. To address these problems, we have combined autologous nasal septum cartilage and conchal cartilage as nasal tip graft materials, which achieve a natural shape and realistic touch postoperatively. From January 2017 to September 2019, a total of 47 patients with nasal septal cartilage combined with conchal cartilage transplantation for nasal tip plasty were screened for a retrospective study. They were followed up and evaluated for 6 to 25 months postoperatively. The operation was performed through an incision in the nose. During the operation, a piece of septal cartilage was cut to make a columella strut. Using one side of the cavitas conchae and cymba conchae cartilage as the graft material, 2 long strips of cartilage were excised for the septum extension graft, and a piece of cap cartilage was transplanted to the top of the nasal tip cartilage scaffold. The time between the operation and follow-up was greater than 6 months, with the range of follow-up and evaluation being from 6 to 25 months. Forty-six patients were satisfied with the shape of the nose. One patient complained that the nasal tip was round and large after 1 month postoperatively, but after 6 months, he was satisfied with the shape of the nasal tip after daily use of a nasal clip. In one male case, the implant was removed more than 7 months postoperatively because of hematoma and infection secondary to nasal trauma. There were 2 cases of nasal tip numbness, both of which recovered spontaneously after 12 months. After the operation, the shape of the nasal tip was round, no cartilage contour was seen on the surface, no collapse of upper nasal tip, no obvious deviation of the nasal dorsum and columella, and no deformation and displacement of the nasal tip cartilage scaffold. At the 6-month follow-up visit, each patient palpated the nasal tip for evaluation. Most patients felt their nose felt realistic and that they had good nasal tip motion. Only 1 patient felt that the nasal tip and the nasal dorsum were moving together when the tip of the nose was being pushed. Nasal septum cartilage and conchal cartilage can be combined as a graft material for reconstruction of the nasal tip. This technique uses different characteristics of each of the 2 cartilages to achieve a more realistic and esthetic outcome.

Matrix-Assisted Bone Marrow Stimulation: A Surgical Technique

Background: Microfracture is an established technique for cartilage regeneration but is limited by many factors such as small defect size, intralesional osteophytes, and lower quality of cartilage regeneration. Therefore, methods to improve results after microfracture like additional matrix augmentation or autologous cell addition are promising techniques. An all-arthroscopic surgical technique for matrix-augmented bone marrow stimulation will be presented here. Indications: Cartilage lesions of moderate size (&gt;1 cm2) that appear too large or unsuitable for pure microfracture but do not yet meet the criteria for autologous cartilage transplantation (&gt;2.5 cm2). The exact size of suitable lesions is currently evolving with only few evidence-based data available. Technique Description: The arthroscopic procedure largely follows the standard microfracture technique. First, the cartilage defect is extensively debrided with removal of calcific cartilage layer. Stable cartilage margins have to be created with removal of all unstable fragments. The resulting well-defined defect is then measured with the use of a marking probe. The subchondral bone is then penetrated and opened using a microfracture awl. Next, the matrix based on hyaluronic acid (Hyalofast) is cut to the appropriate size. All joint fluid is removed, and the matrix is inserted through a previously placed canula and modeled into the defect with the probe. When the defect is well contained, no other fixation material is necessary. Otherwise, the matrix can be additionally fixed using fibrin clue. Cell application (dependent on regulatory issues) can be performed. Before closure, the joint should be moved to ensure safe fixation of the matrix. Results: Currently, there are only insufficient data to exactly define the defect size for microfracture or matrix-assisted bone marrow stimulation. Some studies show an advantage of using biomaterials compared with microfracture alone, but further studies are necessary. Discussion/Conclusion: The presented arthroscopic matrix-assisted bone marrow stimulation is a technically simple, inexpensive way of treating cartilage defects and should therefore be considered when treating affected patients. It can be used in a variety of joints. An additional combination with bone marrow–derived mesenchymal stem cells might be promising but is subject to country-specific regulatory issues.

Closure of Nasal Septal Perforation

Symptomatic nasal septal perforations can lead to a substantial restriction in the quality of life of patients and present a distinct surgical challenge for the otolaryngologist/head and neck surgeon. Symptomatic patients complain about nasal crusting, recurrent nosebleeds and nasal obstruction. The so called 4 bridge-flap technique including the interposition of autologous ear cartilage presents an established surgical method for closure of a septal perforation. In the present article, the surgical procedure is described in detail.

Arthroscopic Autologous Chondrocyte Bone Grafting of a Lateral Tibial Plateau Chondral Defect

Tibial plateau chondral defects can be difficult to diagnose and treat. Although grafting of femoral and patella chondral defects has become relatively commonplace, the tibial plateau offers unique challenges for some of the grafting techniques used in these locations, mostly because of limitations with exposure even in an open approach. Arthroscopic surgery makes treatment of these lesions more feasible, as it affords better access and visualization of tibial defects. The purpose of this article is to describe the arthroscopic management of a lateral tibial plateau chondral defect via autologous chondrocyte bone grafting. The technique consists of harvest of autologous cartilage from the intercondylar notch and repair of the tibial plateau defect with a slurry of autologous chondrocytes and bone marrow aspirate concentrate. In addition, CO2 is used as a medium to distend the joint in a tight compartment to keep the chondral defect dry. This technique is technically simple and does not require an extensive open technique or an expensive osteochondral allograft. It also avoids the staged management required in other types of autologous chondrocyte implantation, which require cartilage biopsy to produce a final product for implantation.

Bioprinting of human nasoseptal chondrocytes‐laden collagen hydrogel for cartilage tissue engineering

Skin cancer patients often have tumorigenic lesions on their noses. Surgical resection of the lesions often results in nasal cartilage removal. Cartilage grafts taken from other anatomical sites are used for the surgical reconstruction of the nasal cartilage, but donor-site morbidity is a common problem. Autologous tissue-engineered nasal cartilage grafts can mitigate the problem, but commercially available scaffolds define the shape and sizes of the engineered grafts during tissue fabrication. Moreover, the engineered grafts suffer from the inhomogeneous distribution of the functional matrix of cartilage.Advances in 3D bioprinting technology offer the opportunity to engineer cartilages with customizable dimensions and anatomically shaped configurations without the inhomogeneous distribution of cartilage matrix. Here, we report the fidelity ofFreeformReversibleEmbedding ofSuspendedHydrogel(FRESH) bioprinting as a strategy to generate customizable and homogenously distributed functional cartilage matrix engineered nasal cartilage. Using FRESH andin vitrochondrogenesis, we have fabricated tissue-engineered nasal cartilage from combining bovine type I collagen hydrogel and human nasoseptal chondrocytes. The engineered nasal cartilage constructs displayed molecular, biochemical and histological characteristics akin to native human nasal cartilage.

Tissue-Adhesive Chondroitin Sulfate Hydrogel for Cartilage Reconstruction.

Chondroitin sulfate (CS), the main component of cartilage extracellular matrix, has attracted attention as a biomaterial for cartilage tissue engineering. However, current CS hydrogel systems still have limitations for application in successful cartilage tissue engineering owing to their unsuitable degradation kinetics, insufficient mechanical similarity, and lack of integration with the native cartilage tissue. In this study, using mussel adhesive-inspired catechol chemistry, we developed a functional CS hydrogel that exhibits tunable physical and mechanical properties as well as excellent tissue adhesion for efficient integration with native tissues. Various properties of the developed catechol-functionalized CS (CS-CA) hydrogel, including swelling, degradation, mechanical properties, and adhesiveness, could be tailored by varying the conjugation ratio of the catechol group to the CS backbone and the concentration of the CS-CA conjugates. CS-CA hydrogels exhibited significantly increased modulus (∼10 kPa) and superior adhesive properties (∼3 N) over conventional CS hydrogels (∼hundreds Pa and ∼0.05 N). In addition, CS-CA hydrogels incorporating decellularized cartilage tissue dice promoted the chondrogenic differentiation of human adipose-derived mesenchymal stem cells by providing a cartilage-like microenvironment. Finally, the transplantation of autologous cartilage dice using tissue-adhesive CS-CA hydrogels enhanced cartilage integration with host tissue and neo-cartilage formation owing to favorable physical, mechanical, and biological properties for cartilage formation. In conclusion, our study demonstrated the potential utility of the CS-CA hydrogel system in cartilage tissue reconstruction.

Clinical Study of Autologous Cartilage Transplantation Based on Nano-Hydroxyapatite in the Treatment of Talar Osteochondral Injury.

Talus osteochondral damage is one of the common symptoms of chronic ankle pain in people's lives. The cartilage regeneration and self-repair ability are extremely limited, the joint cartilage lesions are often accompanied by the lesions of the subchondral bone, and the subchondral bone lesions can affect the metabolism of the cartilage above it, which brings certain difficulties to clinical treatment. Traditional methods of treating cartilage damage include microfractures and drilling. Due to large trauma, inconsistent clinical efficacy reports, poor tissue repair results, and limited donor sources, etc., the application of traditional treatment methods in the clinic has been largely limited. Therefore, finding an ideal treatment method for bone injury has been a hot spot in clinical research in orthopedics. Studies have shown that autologous cartilage transplantation via nano-hydroxyapatite has become a new treatment model, providing new ideas for clinical treatment of talar osteochondral damage. Nano-hydroxyapatite and its composites have good histocompatibility, biological activity, and bone conductivity. They are an ideal bone defect repair material, and have been initially applied in clinical practice. The preparation of nano-hydroxyapatite, its biological characteristics and the repairing effect on the composite defect of osteochondral bone were studied experimentally, and its feasibility for repairing osteochondral damage was discussed. In this paper, the unique structure and properties of natural cartilage layers are studied. In combination with bionics theory and methods, nano-hydroxyapatite micro-particle composite samples are prepared by the gel method, and the bone-forming properties of nano-composites are measured by in vitro drug release experiments. To establish a model of infectious bone injury in New Zealand white rabbits, and nano-hydroxyapatite composites were implanted into local lesions of New Zealand white rabbit models by autologous cartilage transplantation, and evaluated by imaging, blood biochemistry, histology, infection control and bone repair. The experimental results show that using the unique physical and chemical and biological properties of nano-hydroxyapatite materials. It is innovatively introduced into the treatment of talar osteochondral defects caused by open fractures. It has been proven in vitro and in vivo experiments that nano-hydroxyapatite materials can be used. As an ideal tissue engineering scaffold for the treatment of talar osteochondral defects, this provides a new way to solve clinical orthopedic problems using new nanomaterials.