Current surgical options and innovation for repairing articular cartilage defects in the femoral head

Elevated nutrient availability enhances chondrocyte metabolism and biosynthesis in tissue-engineered cartilage

OBJECTIVE

Chondrocytes, which typically rely on anaerobic metabolism, exhibit upregulated biosynthetic activity when subjected to conditions that elicit mixed aerobic-anaerobic metabolism. Previously, we observed that increasing media volume resulted in the transition from anaerobic to mixed aerobic-anaerobic metabolism. Maximal extracellular matrix (ECM) accumulation occurred at this transition as a result of changes in hypoxia-inducible factor 1α signaling and associated hypoxic gene expression. This study aimed to explore the effect of further increases in media availability on ECM synthesis and chondrocyte metabolism.

METHODS

Primary bovine chondrocytes were grown in 3D high-density tissue culture under varying levels of media availability (4-16 mL/106 cells). Changes in ECM accumulation and metabolism were determined through biochemical assays and 13C-metabolic flux analysis (13C-MFA).

RESULTS

Increasing media volumes resulted in higher accumulation of cartilaginous ECM (collagen and proteoglycans) and cellularity. Extracellular metabolite measurements revealed that elevated media availability led to increased glucose and glutamine metabolism, along with increased anaerobic activity. 13C-MFA utilizing [U-13C] glucose demonstrated that increased media availability significantly impacted central carbon metabolism, upregulating all glucose-related metabolic pathways (glycolysis, lactate fermentation, the tricarboxylic acid (TCA) cycle, hexosamine biosynthetic pathway, and the malate-aspartate shuttle). Furthermore, 13C-MFA indicated that glutamine was donating carbons to the TCA cycle, and additional studies involving [U-13C] glutamine tracing supported this notion.

CONCLUSIONS

Elevated media availability upregulates ECM synthesis and leads to significant changes in metabolic phenotype. Glutamine plays an important role in chondrocyte metabolism and increases in glutamine metabolism correlate with increases in ECM accumulation.

Boosting cartilage repair with silk fibroin-DNA hydrogel-based cartilage organoid precursor

Osteoarthritis (OA), a common degenerative disease, is characterized by high disability and imposes substantial economic impacts on individuals and society. Current clinical treatments remain inadequate for effectively managing OA. Organoids, miniature 3D tissue structures from directed differentiation of stem or progenitor cells, mimic native organ structures and functions. They are useful for drug testing and serve as active grafts for organ repair. However, organoid construction requires extracellular matrix-like 3D scaffolds for cellular growth. Hydrogel microspheres, with tunable physical and chemical properties, show promise in cartilage tissue engineering by replicating the natural microenvironment. Building on prior work on SF-DNA dual-network hydrogels for cartilage regeneration, we developed a novel RGD-SF-DNA hydrogel microsphere (RSD-MS) via a microfluidic system by integrating photopolymerization with self-assembly techniques and then modified with Pep-RGDfKA. The RSD-MSs exhibited uniform size, porous surface, and optimal swelling and degradation properties. In vitro studies demonstrated that RSD-MSs enhanced bone marrow mesenchymal stem cells (BMSCs) proliferation, adhesion, and chondrogenic differentiation. Transcriptomic analysis showed RSD-MSs induced chondrogenesis mainly through integrin-mediated adhesion pathways and glycosaminoglycan biosynthesis. Moreover, in vivo studies showed that seeding BMSCs onto RSD-MSs to create cartilage organoid precursors (COPs) significantly enhanced cartilage regeneration. In conclusion, RSD-MS was an ideal candidate for the construction and long-term cultivation of cartilage organoids, offering an innovative strategy and material choice for cartilage regeneration and tissue engineering.

Enhanced articular cartilage regeneration using costal chondrocyte-derived scaffold-free tissue engineered constructs with ascorbic acid treatment

Background

Cartilage tissue engineering faces challenges related to the use of scaffolds and limited seed cells. This study aims to propose a cost-effective and straightforward approach using costal chondrocytes (CCs) as an alternative cell source to overcome these challenges, eliminating the need for special culture equipment or scaffolds.

Methods

CCs were cultured at a high cell density with and without ascorbic acid treatment, serving as the experimental and control groups, respectively. Viability and tissue-engineered constructs (TEC) formation were evaluated until day 14. Slices of TEC samples were used for histological staining to evaluate the secretion of glycosaminoglycans and different types of collagen proteins within the extracellular matrix. mRNA sequencing and qPCR were performed to examine gene expression related to cartilage matrix secretion in the chondrocytes. In vivo experiments were conducted by implanting TECs from different groups into the defect site, followed by sample collection after 12 weeks for histological staining and scoring to evaluate the extent of cartilage regeneration. Hematoxylin-eosin (HE), Safranin-O-Fast Green, and Masson's trichrome stainings were used to examine the content of cartilage-related matrix components in the in vivo repair tissue. Immunohistochemical staining for type I and type II collagen, as well as aggrecan, was performed to assess the presence and distribution of these specific markers. Additionally, immunohistochemical staining for type X collagen was used to observe any hypertrophic changes in the repaired tissue.

Results

Viability of the chondrocytes remained high throughout the culture period, and the TECs displayed an enriched extracellular matrix suitable for surgical procedures. In vitro study revealed glycosaminoglycan and type II collagen production in both groups of TEC, while the TEC matrix treated with ascorbic acid displayed greater abundance. The results of mRNA sequencing and qPCR showed that genes related to cartilage matrix secretion such as Sox9, Col2, and Acan were upregulated by ascorbic acid in costal chondrocytes. Although the addition of Asc-2P led to an increase in COL10 expression according to qPCR and RNA-seq results, the immunofluorescence staining results of the two groups of TECs exhibited similar distribution and fluorescence intensity. In vivo experiments showed that both groups of TEC could adhere to the defect sites and kept hyaline cartilage morphology until 12 weeks. TEC treated with ascorbic acid showed superior cartilage regeneration as evidenced by significantly higher ICRS and O'Driscoll scores and stronger Safranin-O and collagen staining mimicking native cartilage when compared to other groups. In addition, the immunohistochemical staining results of Collgan X indicated that, after 12 weeks, the ascorbic acid-treated TEC did not exhibit further hypertrophy upon transplantation into the defect site, but maintained an expression profile similar to untreated TECs, while slightly higher than the sham-operated group.

Conclusion

These results suggest that CC-derived scaffold-free TEC presents a promising method for articular cartilage regeneration. Ascorbic acid treatment enhances outcomes by promoting cartilage matrix production. This study provides valuable insights and potential advancements in the field of cartilage tissue engineering.

The translational potential of this article

Cartilage tissue engineering is an area of research with immense clinical potential. The approach presented in this article offers a cost-effective and straightforward solution, which can minimize the complexity of cell culture and scaffold fabrication. This simplification could offer several translational advantages, such as ease of use, rapid scalability, lower costs, and the potential for patient-specific clinical translation. The use of costal chondrocytes, which are easily obtainable, and the scaffold-free approach, which does not require specialized equipment or membranes, could be particularly advantageous in clinical settings, allowing for in situ regeneration of cartilage.

High-Speed Centrifugation Efficiently Removes Immunogenic Elements in Osteochondral Allografts

OBJECTIVES

The current clinical pulse lavage technique for flushing fresh osteochondral allografts (OCAs) to remove immunogenic elements from the subchondral bone is ineffective. This study aimed to identify the optimal method for removing immunogenic elements from OCAs.

METHODS

We examined five methods for the physical removal of immunogenic elements from OCAs from the femoral condyle of porcine knees. We distributed the OCAs randomly into the following seven groups: (1) control, (2) saline, (3) ultrasound, (4) vortex vibration (VV), (5) low-pulse lavage (LPL), (6) high-pulse lavage (HPL), and (7) high-speed centrifugation (HSC). OCAs were evaluated using weight measurement, micro-computed tomography (micro-CT), macroscopic and histological evaluation, DNA quantification, and chondrocyte activity testing. Additionally, the subchondral bone was zoned to assess the bone marrow and nucleated cell contents. One-way ANOVA and paired two-tailed Student's t-test are used for statistical analysis.

RESULTS

Histological evaluation and DNA quantification showed no significant reduction in marrow elements compared to the control group after the OCAs were treated with saline, ultrasound, or VV treatments; however, there was a significant reduction in marrow elements after LPL, HPL, and HSC treatments. Furthermore, HSC more effectively reduced the marrow elements of OCAs in the middle and deep zones compared with LPL (p < 0.0001) and HPL (p < 0.0001). Macroscopic evaluation revealed a significant reduction in blood, lipid, and marrow elements in the subchondral bone after HSC. Micro-CT, histological analyses, and chondrocyte viability results showed that HSC did not damage the subchondral bone and cartilage; however, LPL and HPL may damage the subchondral bone.

CONCLUSION

HSC may play an important role in decreasing immunogenicity and therefore potentially increasing the success of OCA transplantation.

Osteochondral Allograft or Autograft Transplantation of the Femoral Head Leads to Improvement in Outcomes but Variable Survivorship: A Systematic Review

PURPOSE

To review patient-reported outcomes (PROs) and survivorship in patients undergoing osteochondral autograft or allograft transplantation (OAT) of the femoral head.

METHODS

PubMed, Cochrane Center for Register of Controlled Trials, and Scopus databases were searched in November 2022 with an updated search extending to December 2023 using criteria from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the following keywords: (hip OR femoral head) AND (mosaicplasty OR osteochondral allograft OR osteochondral autograft OR osteochondral lesion). Articles were included if they evaluated postoperative PROs in patients who underwent OAT of the femoral head and had a study size of 5 or more hips (n ≥ 5). Survivorship was defined as freedom from conversion to total hip arthroplasty. For PROs evaluated in 3 studies or more, forest plots were created and I2 was calculated.

RESULTS

Twelve studies were included in this review, with a total of 156 hips and a mean follow-up time ranging between 16.8 and 222 months. In total, 104 (66.7%) hips were male while 52 (33.3%) were female. Age of patients ranged from 17.0 to 35.4 years, while body mass index ranged from 23.3 to 28.1. Eight studies reported on osteochondral autograft transplantation and 4 studies on osteochondral allograft transplantation. Three studies reported significant improvement in at least 1 PRO. Survivorship ranged from 61.5% to 96% at minimum 2-year follow-up and from 57.1% to 91% at minimum 5-year follow-up. At a follow-up of less than 5 years, osteochondral allograft transplantation studies showed 70% to 87.5% survivorship, while autograft varied from 61.54% to 96%.

CONCLUSIONS

Patients with osteochondral lesions of the femoral head who underwent osteochondral autograft or allograft transplantation demonstrated improved PROs but variable survivorship rates.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Partial femoral head replacement: a new innovative hip-preserving approach for treating osteonecrosis of the femoral head and its finite element analysis

Purpose: Controversy remains regarding the optimal treatment for stage III Osteonecrosis of the femoral head (ONFH). This study presents, for the first time, the precise treatment of stage III ONFH using the "substitute the beam for a pillar" technique and performs a comparative finite element analysis with other hip-preserving procedures. Methods: A formalin-preserved femur of male cadavers was selected to obtain the CT scan data of femur. The proximal femur model was reconstructed and assembled using Mimics 20.0, Geomagic, and UG-NX 12.0 software with four different implant types: simple core decompression, fibula implantation, porous tantalum rod implantation, and partial replacement prosthesis. The finite element simulations were conducted to simulate the normal walking gait, and the stress distribution and displacement data of the femur and the implant model were obtained. Results: The peak von Mises stress of the femoral head and proximal femur in the partial replacement of the femoral head (PRFH) group were 22.8 MPa and 37.4 MPa, respectively, which were 3.1%-38.6% and 12.8%-37.4% lower than those of the other three surgical methods. Conclusion: The PRFH group exhibits better mechanical performance, reducing stress and displacement in the ONFH area, thus maintaining femoral head stability. Among the four hip-preserving approaches, from a biomechanical perspective, PRFH offers a new option for treating ONFH.

Effects of glycosaminoglycan content in extracellular matrix of donor cartilage on the functional properties of osteochondral allografts evaluated by micro-CT non-destructive analysis

Osteochondral allograft (OCA) is an important surgical procedure used to repair extensive articular cartilage damage. It is known that chondrocyte viability is crucial for maintaining the biochemical and biomechanical properties of OCA, which is directly related to the clinical success of the operation and is the only standard for preoperative evaluation of OCA. However, there is a lack of systematic research on the effect of the content of cellular matrix in OCA cartilage tissue on the efficacy of transplantation. Therefore, we evaluated the effect of different GAG contents on the success of OCA transplantation in a rabbit animal model. Each rabbit OCA was treated with chondroitinase to regulate glycosaminoglycan (GAG) content in the tissue. Due to the different action times of chondroitinase, they were divided into 4 experimental groups (including control group, 2h, 4h, and 8h groups). The treated OCAs of each group were used for transplantation. In this study, transplant surgery effects were assessed using micro-computed tomography (μCT) and histological analysis. Our results showed that tissue integration at the graft site was poorer in the 4h and 8h groups compared to the control group at 4 and 12 weeks in vivo, as were the compressive modulus, GAG content, and cell density reduced. In conclusion, we evaluated the biochemical composition of OCAs before and after surgery using μCT analysis and demonstrated that the GAG content of the graft decreased, it also decreased during implantation; this resulted in decreased chondrocyte viability after transplantation and ultimately affected the functional success of OCAs.

Cartilage biomechanics: From the basic facts to the challenges of tissue engineering

Articular cartilage (AC) is the thin tissue that covers the long bone ends in the joints and that ensures the transmission of forces between adjacent bones while allowing nearly frictionless movements between them. AC repair is a technologic and scientific challenge that has been addressed with numerous approaches. A major deadlock is the capacity to take in account its complex mechanical properties in repair strategies. In this review, we first describe the major mechanical behaviors of AC for the non-specialists. Then, we show how researchers have progressively identified specific mechanical parameters using mathematical models. There are still gaps in our understanding of some of the observations concerning AC biomechanical properties, particularly the differences in extracellular matrix stiffness measured at the microscale and at the millimetric scale. Nevertheless, for bioengineering applications, AC repair strategies must take into account what are commonly considered the main mechanical features of cartilage: its ability to withstand high stresses through three main behaviors (elasticity, poroelasticity and swelling). Finally, we emphasize that future studies need to investigate AC mechanical properties at different scales, particularly the gradient of mechanical properties around cells and across the cartilage depth, and the differences in mechanical properties at different scales. This multi-scale approach could greatly enhance the success of AC restorative approaches.

Femoral head fracture with large crushed defect in weight-bearing area treated with autologous osteochondral transplantation (repositionplasty): A case report

RATIONALE

Femoral head fracture is a rare type of fracture commonly associated with hip dislocation. Femoral head fracture treatments include conservative treatment, fragment excision, open reduction, internal fixation, and arthroplasty. In cases of young patients, open reduction and internal fixation are preferred over arthroplasty. Pipkin type 2 fractures are treated with open reduction and internal fixation in most cases because the fracture line extends upward of the fovea and includes the femoral head-acetabular weight-bearing joint surface. However, if the fracture is severely comminuted or crushed, good results are difficult to obtain with open reduction and internal fixation.

PATIENT CONCERNS

A 23-years-old male patient presented to the emergency room with right hip pain after 4-m fall.

DIAGNOSIS

In initial image work up, he was diagnosed with right posterior hip dislocation and a Pipkin type 2 femoral head fracture with an ipsilateral superior ramus fracture. After manual reduction, simple radiography and computed tomography showed reduction of the hip joint and a large osteochondral defect of approximately 6 cm2 in the weight-bearing area on the superomedial side of the femoral head.

INTERVENTIONS

This was treated with a novel surgery named autologous osteochondral transplantation (repositionplasty), devised by the authors.

OUTCOMES

The congruent reduction was confirmed by radiography and computed tomography immediately after the surgery. At 5 years postoperatively, the Harris Hip Score was 100 points and no discomfort, femoral head collapse, osteonecrosis, or traumatic arthritis were observed on follow-up radiographs.

LESSONS

We think this method "repositionplasty" will be a good treatment method for young patients with a large defect in the weight-bearing part of the femoral head who cannot undergo open reduction and internal fixation.

Autologous Costal Cartilage Grafting for a Large Osteochondral Lesion of the Femoral Head: A 1-Year Single-Arm Study with 2 Additional Years of Follow-up

BACKGROUND

There is currently no ideal treatment for osteochondral lesions of the femoral head (OLFH) in young patients.

METHODS

We performed a 1-year single-arm study and 2 additional years of follow-up of patients with a large (defined as >3 cm 2 ) OLFH treated with insertion of autologous costal cartilage graft (ACCG) to restore femoral head congruity after lesion debridement. Twenty patients ≤40 years old who had substantial hip pain and/or dysfunction after nonoperative treatment were enrolled at a single center. The primary outcome was the change in Harris hip score (HHS) from baseline to 12 months postoperatively. Secondary outcomes included the EuroQol visual analogue scale (EQ VAS), hip joint space width, subchondral integrity on computed tomography scanning, repair tissue status evaluated with the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, and evaluation of cartilage biochemistry by delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T2 mapping.

RESULTS

All 20 enrolled patients (31.02 ± 7.19 years old, 8 female and 12 male) completed the initial study and the 2 years of additional follow-up. The HHS improved from 61.89 ± 6.47 at baseline to 89.23 ± 2.62 at 12 months and 94.79 ± 2.72 at 36 months. The EQ VAS increased by 17.00 ± 8.77 at 12 months and by 21.70 ± 7.99 at 36 months (p < 0.001 for both). Complete integration of the ACCG with the bone was observed by 12 months in all 20 patients. The median MOCART score was 85 (interquartile range [IQR], 75 to 95) at 12 months and 75 (IQR, 65 to 85) at the last follow-up (range, 24 to 38 months). The ACCG demonstrated magnetic resonance properties very similar to hyaline cartilage; the median ratio between the relaxation times of the ACCG and recipient cartilage was 0.95 (IQR, 0.90 to 0.99) at 12 months and 0.97 (IQR, 0.92 to 1.00) at the last follow-up.

CONCLUSIONS

ACCG is a feasible method for improving hip function and quality of life for at least 3 years in young patients who were unsatisfied with nonoperative treatment of an OLFH. Promising long-term outcomes may be possible because of the good integration between the recipient femoral head and the implanted ACCG.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Mosaicplasty of the Femoral Head: A Systematic Review and Meta-Analysis of the Current Literature

Osteochondral lesions of the femoral head are rare. For the treatment of these lesions, various joint-preserving procedures, particularly in young, active patients, have been developed. Mosaicplasty is a well-established surgical procedure for the knee. However, there is little evidence that this method can also be used to treat osteochondral lesions in the hip. The indication for cartilage procedures continues to evolve for the knee, and a similar strategy may be adopted for the hip joint. Due to limited evidence and a lack of experience, mosaicplasty treatment of these lesions remains challenging, especially in young patients. This study shows that open and arthroscopic management using the knee and femoral head as donor sites yielded good to excellent short- to mid-term outcomes. For osteochondral lesions of the femoral head, mosaicplasty may be a new alternative treatment option, although this needs to be proven with longer follow-ups and in a larger sample of patients.

Decellularized extracellular matrix loaded with IPFP-SC for repairing rabbit osteochondral defects

BACKGROUND

Tissue engineering is widely applied to treat osteochondral damage in osteoarthritis (OA). However, the superposition of seed cells, material scaffolds, inducing factors, and microenvironmental factors limit their practical application. We intended to develop a novel tissue engineering method for improving the repairment of osteochondral damage and to discuss its effect on repairing osteochondral defects.

METHODS

The combined decellularization methods of physics, chemistry and enzymes were used to decellularize rabbit rib cartilage and articular cartilage, and rabbit decellularizated osteochondral composite scaffolds were prepared. The structure and organization of the scaffolds were analyzed. We extracted and identified infrapatellar fat pad stem cells (IPFP-SCs) from healthy rabbits and OA rabbit, which were different in viability, migration, osteogenic and chondrogenic differentiation. Finally, a variety of decellularizated bone cartilage composite scaffolds were loaded with rabbit IPFP-SC for in vitro and in vivo studies.

RESULTS

The decellularization effect was strong, and the organic ingredients were lost. The layered scaffold showed lower density, greater porosity, larger pore size and water absorption than the whole scaffold, but the mechanical properties of the two scaffolds were low. IPFP-SCs were successfully extracted, and the migration and cartilage ability of IPFP-SCs in OA group were weak. The decellularized scaffold showed a high biocompatibility. The structure and composition of osteochondral promoted osteogenic differentiation and chondrogenic differentiation of IPFP-SCs. Moreover, the decellularized extracellular matrix loaded with IPFP-SC had the strongest repairing effect.

CONCLUSION

The decellularized extracellular matrix loaded with IPFP-SC showed a better repair effect on rabbit osteochondral defects.

Comparison between Intra-Articular Injection of Infrapatellar Fat Pad (IPFP) Cell Concentrates and IPFP-Mesenchymal Stem Cells (MSCs) for Cartilage Defect Repair of the Knee Joint in Rabbits

Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic method in regenerative medicine. Our previous research adopted a simple nonenzymatic strategy for the preparation of a new type of ready-to-use infrapatellar fat pad (IPFP) cell concentrates. The aim of this study was to compare the therapeutic efficacy of intra-articular (IA) injection of autologous IPFP cell concentrates and allogeneic IPFP-MSCs obtained from these concentrates in a rabbit articular cartilage defect model. IPFP-MSCs sprouting from the IPFP cell concentrates were characterized via flow cytometry as well as based on their potential for differentiation into adipocytes, osteoblasts, and chondrocytes. In the rabbit model, cartilage defects were created on the trochlear groove, followed by treatment with IPFP cell concentrates, IPFP-MSCs, or normal saline IA injection. Distal femur samples were evaluated at 6 and 12 weeks posttreatment via macroscopic observation and histological assessment based on the International Cartilage Repair Society (ICRS) macroscopic scoring system as well as the ICRS visual histological assessment scale. The macroscopic score and histological score were significantly higher in the IPFP-MSC group compared to the IPFP cell concentrate group at 12 weeks. Further, both treatment groups had higher scores compared to the normal saline group. In comparison to the latter, the groups treated with IPFP-MSCs and IPFP cell concentrates showed considerably better cartilage regeneration. Overall, IPFP-MSCs represent an effective therapeutic strategy for stimulating articular cartilage regeneration. Further, due to the simple, cost-effective, nonenzymatic, and safe preparation process, IPFP cell concentrates may represent an effective alternative to stem cell-based therapy in the clinic.

Unusual apical femoral head deformity treated by hip arthroscopy and tunnel drilling through femoral head: a case report

Femoro-acetabular impingement (FAI), is the result of an abnormal morphology of the hip joint. On the femoral side, asphericity of the head can be highlighted by an alpha angle measurement >50° on computed tomography or MRI. However, some particular cephalic asphericities can make it difficult to measure the alpha angle, leading to a diagnostic pitfall. While in the classic cam effect, the deformity is peripheral and can be treated by arthroscopic femoroplasty, an apical head deformity remains a therapeutic challenge. We present the case of a 17-year-old male patient with a femoral head deformity, corresponding to an ISHA zone 6 overhang, significantly improved in everyday and sports life by arthroscopic trapdoor technique to resect the focal central deformity while enabling concomitant treatment of central compartment pathology, in this case, a hypertrophic ligamentum teres and femoral head chondral flap. Etiology of this femoral head deformity remains uncertain but could be a particular cam deformity, sequelae to pediatric disease or instability with repeated traction of the ligament teres on the femoral head apical insertion during cephalic growth.

Effect of the medial collateral ligament and the lateral ulnar collateral ligament injury on elbow stability: a finite element analysis

Ligaments are the most important stabilizer of elbow. However, the stress of ligaments is hard to measure because of the complex biomechanical environment in the elbow. Our objective was to develop a human elbow finite element model and to validate it by a comparison with previous experimental data. Then several different ligaments injury conditions and elbow flexion were simulated to analyse the elbow instability and to stress the biomechanical consequences. The computational investigation of different effects of ligament constraints of elbow was studied by means of finite element analysis. The stress of the anterior bundle was almost greater than other ligaments in all conditions, which played the most important role during the elbow flexion. The posterior bundle was the secondary stabilizer during flexion after the anterior bundle. The lateral ulnar collateral ligament (LUCL) injury could result in an increase of the ulnar cartilage stress. The anterior bundle and the LUCL were recommended to be repaired in elbow joint dislocations and fractures. This study could help understand the dynamic effects of ligaments on the joint over the entire extension by investigating the tissue stress.

Recent Developments in Clinical Applications of Mesenchymal Stem Cells in the Treatment of Rheumatoid Arthritis and Osteoarthritis

Mesenchymal stem cell (MSC) therapies have been used as cell-based treatments for decades, owing to their anti-inflammatory, immunomodulatory, and regenerative properties. With high expectations, many ongoing clinical trials are investigating the safety and efficacy of MSC therapies to treat arthritic diseases. Studies on osteoarthritis (OA) have shown positive clinical outcomes, with improved joint function, pain level, and quality of life. In addition, few clinical MSC trials conducted on rheumatoid arthritis (RA) patients have also displayed some optimistic outlook. The largely positive outcomes in clinical trials without severe side effects establish MSCs as promising tools for arthritis treatment. However, further research is required to investigate its applicability in clinical settings. This review discusses the most recent advances in clinical studies on MSC therapies for OA and RA.

Repair of articular cartilage defect using adipose-derived stem cell-loaded scaffold derived from native cartilage extracellular matrix

The purpose of this study was to investigate the feasibility of adipose-derived stem cells (ADSCs) as the seed cells of cartilage tissue engineering. ADSCs were isolated from adipose tissue that was harvested under sterile conditions from the inguen fold of porcines and cultured in vitro. Acellular cartilage extracellular matrix (ACECM) scaffolds of pigs were then constructed. Moreover, inflammatory cells, as well as cellular and humoral immune responses, were detected using hematoxylin and eosin staining staining, immunohistochemical staining, and western blot analysis. The results showed that the cartilage complex constructed by ADSCs and ACECM through tissue engineering successfully repaired the cartilage defect of the pig knee joint. The in vivo repair experiment showed no significant difference between chondrocytes, ADSCs, and induced ADSCs, indicating that ADSCs do not require in vitro induction and have the potential for chondrogenic differentiation in the environment around the knee joint. In addition, pig-derived acellular cartilage scaffolds possess no obvious immune inflammatory response when used in xenotransplantation. ADSCs may serve as viable seed cells for cartilage tissue engineering.