Reconstruction of medial meniscus posterior portion deficiency in pigs with an autologous patellar tendon graft: an experimental study.

OBJECTIVE: This study was performed to investigate the effectiveness of two surgical procedures, autologous patellar tendon graft reconstruction and trans-tibial plateau pull-out repair, using a pig model. The primary focus was to assess the repair capability of medial meniscus posterior portion (MMPP) deficiency, the overall structural integrity of the meniscus, and protection of the femoral and tibial cartilage between the two surgical groups. The overall aim was to provide experimental guidelines for clinical research using these findings. METHODS: Twelve pigs were selected to establish a model of injury to the MMPP 10 mm from the insertion point of the tibial plateau. They were randomly divided into three groups of four animals each: reconstruction (autologous tendon graft reconstruction of the MMPP), pull-out repair (suture repair of the MMPP via a trans-tibial plateau bone tunnel), and control (use of a normal medial meniscus as the negative control). The animals were euthanized 12 weeks postoperatively for evaluation of the meniscus, assessment of tendon bone healing, and gross observation of knee joint cartilage. The tibial and femoral cartilage injuries were evaluated using the International Society for Cartilage Repair (ICRS) grade and Mankin score. Histological and immunohistochemical staining was conducted on the meniscus-tendon junction area, primary meniscus, and tendons. The Ishida score was used to evaluate the regenerated meniscus in the reconstruction group. Magnetic resonance imaging (MRI) was used to evaluate meniscal healing. RESULTS: All 12 pigs recovered well after surgery; all incisions healed without infection, and no obvious complications occurred. Gross observation revealed superior results in the reconstruction and pull-out repair groups compared with the control group. In the tibial cartilage, the reconstruction group had ICRS grade I injury whereas the pull-out repair and control groups had ICRS grade II and III injury, respectively. The Mankin score was significantly different between the reconstruction and control groups; histological staining showed that the structure of the regenerated meniscus in the reconstruction group was similar to that of the original meniscus. Immunohistochemical staining showed that the degree of type I and II collagen staining was similar between the regenerated meniscus and the original meniscus in the reconstruction group. The Ishida score was not significantly different between the regenerated meniscus and the normal primary meniscus in the reconstruction group. MRI showed that the MMPP in the reconstruction and pull-out repair groups had fully healed, whereas that in the control group had not healed. CONCLUSION: Autologous patellar tendon graft reconstruction of the MMPP can generate a fibrocartilage-like regenerative meniscus. Both reconstruction and pull-out repair can preserve the structural integrity of the meniscus, promote healing of the MMPP, delay meniscal degeneration, and protect the knee cartilage.

HWJMSC-EVs promote cartilage regeneration and repair via the ITGB1/TGF-ß/Smad2/3 axis mediated by microfractures.

The current first-line treatment for repairing cartilage defects in clinical practice is the creation of microfractures (MF) to stimulate the release of mesenchymal stem cells (MSCs); however, this method has many limitations. Recent studies have found that MSC-derived extracellular vesicles (MSC-EVs) play an important role in tissue regeneration. This study aimed to verify whether MSC-EVs promote cartilage damage repair mediated by MFs and to explore the repair mechanisms. In vitro experiments showed that human umbilical cord Wharton's jelly MSC-EVs (hWJMSC-EVs) promoted the vitality of chondrocytes and the proliferation and differentiation ability of bone marrow-derived MSCs. This was mainly because hWJMSC-EVs carry integrin beta-1 (ITGB1), and cartilage and bone marrow-derived MSCs overexpress ITGB1 after absorbing EVs, thereby activating the transforming growth factor-ß/Smad2/3 axis. In a rabbit knee joint model of osteochondral defect repair, the injection of different concentrations of hWJMSC-EVs into the joint cavity showed that a concentration of 50 µg/ml significantly improved the formation of transparent cartilage after MF surgery. Extraction of regenerated cartilage revealed that the changes in ITGB1, transforming growth factor-ß, and Smad2/3 were directly proportional to the repair of regenerated cartilage. In summary, this study showed that hWJMSC-EVs promoted cartilage repair after MF surgery.

Dual-tissue transplantation versus osteochondral autograft transplantation in the treatment of osteochondral defects: a porcine model study.

BACKGROUND: Osteochondral injury is a common sports injury, and hyaline cartilage does not regenerate spontaneously when injured. However, there is currently no gold standard for treating osteochondral defects. Osteochondral autograft transplantation (OAT) is widely used in clinical practice and is best used to treat small osteochondral lesions in the knee that are < 2 cm2 in size. Autologous dual-tissue transplantation (ADTT) is a promising method with wider indications for osteochondral injuries; however, ADTT has not been evaluated in many studies. This study aimed to compare the radiographic and histological results of ADTT and OAT for treating osteochondral defects in a porcine model. METHODS: Osteochondral defects were made in the bilateral medial condyles of the knees of 12 Dian-nan small-ear pigs. The 24 knees were divided into the ADTT group (n = 8), OAT group (n = 8), and empty control group (n = 8). At 2 and 4 months postoperatively, the knees underwent gross evaluation based on the International Cartilage Repair Society (ICRS) score, radiographic assessment based on CT findings and the magnetic resonance observation of cartilage repair tissue (MOCART) score, and histological evaluation based on the O'Driscoll histological score of the repair tissue. RESULTS: At 2 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score were significantly better in the OAT group than the ADTT group (all P < 0.05). At 4 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score tended to be better in the OAT group than the ADTT group, but these differences did not reach statistical significance (all P > 0.05). CONCLUSIONS: In a porcine model, ADTT and OAT are both effective treatments for osteochondral defects in weight bearing areas. ADTT may be useful as an alternative procedure to OAT for treating osteochondral defects.

Overloaded axial stress activates the Wnt/ß-Catenin pathway in nucleus pulposus cells of adult degenerative scoliosis combined with intervertebral disc degeneration.

BACKGROUND: Intervertebral disc degeneration (IVDD) is the initiating factor of adult degenerative scoliosis (ADS), and ADS further accelerates IVDD, creating a vicious cycle. Nevertheless, the role of the Wnt/ß-Catenin pathway in ADS combined with IVDD (ADS-IVDD) remains a mystery. Accordingly, this study was proposed to investigate the effect of axial stress on the Wnt/ß-Catenin pathway in nucleus pulposus cells (NPCs) isolated from DS-IVDD patients. METHODS: Normal NPCs (N-NPC) were purchased and the NPCs of young (25-30 years; Y-NPC) and old (65-70 years; O-NPC) from ADS-IVDD patients were primary cultured. After treatment of NPC with overloaded axial pressure, CCK-8 and Annexin V-FITC kits were applied for detecting proliferation and apoptosis of N-NPC, Y-NPC and O-NPC, and western blotting was performed to assess the expression of Wnt 3a, ß-Catenin, NPC markers and apoptosis markers (Bax, Bcl2 and Caspase 3). RESULTS: N-NPC, Y-NPC and O-NPC were mainly oval, polygonal and spindle-shaped with pseudopods, and the cell morphology tended to be flattened with age. N-NPC, Y-NPC and O-NPC were capable of synthesizing proteoglycans and expressing the NPC markers (Collagen II and Aggrecan). Notably, the expression of Wnt 3a, ß-Catenin, Collagen II and Aggrecan was reduced in N-NPC, Y-NPC and O-NPC in that order. After overload axial stress treatment, cell viability of N-NPC and Y-NPC was significantly reduced, and the percentage of apoptosis and expression of Wnt 3a and ß-Catenin were significantly increased. CONCLUSIONS: Overloaded axial pressure activates the Wnt/ß-Catenin pathway to suppress proliferation and facilitate apoptosis of NPC in ADS-IVDD patients.

A Pain That is Easily Overlooked: Referred Pain Caused by OVCF.

Purpose: The objective of this study was to analyze the clinical characteristics and the therapeutic effects of treatment at our spinal center in OVCF patients associated with referred pain. The underlying goals were to deepen the understanding of referred pain caused by OVCFs, improve the currently low early diagnosis rate of OVCFs, and improve the effectiveness of treatment. Methods: The patients who had referred pain from OVCFs and met the inclusion criteria were retrospectively analyzed. All patients were treated with percutaneous kyphoplasty (PKP). Visual analog scale (VAS) scores and Oswestry Disability Index (ODI) were used to evaluate the therapeutic effect at different time points. Results: There were 11 males (19.6%) and 45 females (80.4%). Their corresponding mean bone mineral density (BMD) value was -3.3 ± 0.4. The regression coefficient of BMD in the linear regression equation was -4.51 (P<0.001). According to the classification system for referred pain in OVCFs, there were 27 cases of type A (48.2%), 12 cases of type B (21.2%), 8 cases of type C (14.3%), 3 cases of type D (5.4%), and 6 cases of type E (10.7%). All patients were followed up for at least 6 months, and both VAS scores and ODI were found to be significantly better postoperatively than preoperatively (P<0.001). There was no significant difference in VAS scores and ODI between different types preoperatively or 6 months postoperatively (P > 0.05). Within each type, there were significant differences in VAS scores and ODI between the pre- and postoperative timepoints (P < 0.05). Conclusion: Attention should be paid to referred pain in OVCF patients, which is not uncommon in clinical practice. Our summary of the characteristics of referred pain caused by OVCFs can improve the early diagnosis rate of OVCFs patients and provide a reference for their prognosis after PKP.

In vitro dynamic perfusion of prevascularized OECs-DBMs (outgrowth endothelial progenitor cell - demineralized bone matrix) complex fused to recipient vessels in an internal inosculation manner.

The current research on seed cells and scaffold materials of bone tissue engineering has achieved milestones. Nevertheless, necrosis of seed cells in center of bone scaffold is a bottleneck in tissue engineering. Therefore, this study aimed to investigate the in vivo inosculation mechanism of recipient microvasculature and prevascularized outgrowth endothelial progenitor cells (OECs)-demineralized bone matrix (DBM) complex. A dorsal skinfold window-chamber model with tail vein injection of Texas red-dextran was established to confirm the optimal observation time of microvessels. OECs-DBM complex under static and dynamic perfusion culture was implanted into the model to analyze vascularization. OECs-DBM complex was harvested on 12th day for HE staining and fluorescent imaging. The model was successfully constructed, and the most appropriate time to observe microvessels was 15 min after injection. The ingrowth of recipient microvessels arcoss the border of OECs-DBM complex increased with time in both groups, and more microvessels across the border were observed in dynamic perfusion group on 3rd, 5th, 7th day. Fluorescent integrated density of border in dynamic perfusion group was higher at all-time points, and the difference was more significant in central area. Fluorescent imaging of OECs-DBM complex exhibited that no enhanced green fluorescent protein-positive cells were found beyond the verge of DBM scaffold in both groups. In vitro prevascularization by dynamic perfusion culture can increase and accelerate the blood perfusion of OECs-DBM complex obtained from recipient microvasculature by internal inosculation. Accordingly, this approach may markedly contribute to the future success of tissue engineering applications in clinical practice.

The most economical arthroscopic suture fixation for tibial intercondylar eminence avulsion fracture without any implant.

BACKGROUND: Avulsion fracture of the tibial intercondylar eminence is a rare injury, which mainly occurs in adolescents aged 8-14 years and in those with immature bones. The current commonly used surgery may result in severe surgical trauma, affecting knee joint function and accompanied by serious complications. In this study, we described an all-inside and all-epiphyseal arthroscopic suture fixation technique for a patient to treat tibial intercondylar eminence fracture. METHODS: ETHIBOND EXCEL-coated braided polyester sutures were used for fixation. Three ETHIBOND sutures were passed through the ACL at 2, 6 and 10 o'clock of the footprint of the ACL and made a cinch-knot loop separately. Under the guidance of ACL tibial locator, three corresponding tibial tunnels were drilled with K-wires at 2, 6 and 10 o'clock of the fracture bed, and the two ends of the suture were pulled out through the tunnel with double-folded steel wire heads. After reduction of the tibial eminence, three sutures were tightened and tied to the medial aspect of the tibial tubercle. RESULTS: After all the surgical treatments surgically performed by this method and following a standard postoperative protocol, our patient's ROM, stability, and functional structural scores all improved significantly. CONCLUSION: This three-point suture technique provides a suitable reduction and stable fixation and is suitable for patients with all types of avulsion fractures of the tibial intercondylar eminence.

Hip Arthroscopic Reduction and Fixation for Adolescent Acetabular Posterior Wall Fracture: A Case Report.

BACKGROUND: Posterior wall fracture is the most common type of acetabular fracture, the traditional open reduction and fixation through the Kocher-Langenbeck approach required a large incision and extensive muscle and soft tissue dissection, resulting in more blood loss, more complications and delayed recovery after the operation. Hip arthroscopy has been widely used in clinical practice but rarely reported in acetabular fractures. CASE PRESENTATION: We present the case of a 14-year-old boy with acetabular posterior wall fracture who was treated with hip arthroscopy reduction and fixation using anchors. He began to walk with partial weight-bearing assisted by double crutches, and returned to school with crutches at 3 days after surgery. Although hip arthroscopy is technically more demanding, it's an optimal choice for selected patients of acetabular fracture with the advantages of less invasive and faster postoperative recovery.

[Digital subtraction angiography assisted musculoskeletal flap transplantation for the treatment of osteonecrosis of the femoral head].

OBJECTIVE: To observe the effectiveness of digital subtraction angiography (DSA) assisted musculoskeletal flap transplantation in the treatment of osteonecrosis of the femoral head (ONFH). METHODS: The clinical data of 15 patients with 15 hips of ONFH admitted between January 2016 and December 2019 were retrospectively analyzed. All patients were male, aged 20-45 years, with an average age of 31.6 years. There were hormone type in 9 cases and alcohol type in 6 cases. The disease duration ranged from 15 days to 3 years, with an average of 8 months. The Association Research Circulation Osseous (ARCO) staging: 4 hips in stage Ⅱ, 11 hips in stage Ⅲ. The preoperative visual analogue scale (VAS) score was 6.2±0.2, and the Harris score of the hip joint was 57.3±1.3. Preoperative DSA examination of the femoral head was performed to determine the location of vascular lesions of the femoral head. According to the results of the angiography, the surgical selection of the musculoskeletal flap was guided. For the patients with both superior and inferior retinaculum vessels developed, simple core decompression was performed. For the patients with superior retinaculum vessels developed but inferior retinaculum vessels not developed, anterolateral tensor fasciae flap was used. For the patients whose superior retinaculum did not develop and the inferior retinaculum developed, posterolateral quadratus femoris flap was used. The fibular flap with anastomotic vessels was used in the patients whose superior and inferior retinaculum vessels were not developed. RESULTS: All 15 cases of 15 hips were followed up 6-24 months, with an average of 14 months. During the follow-up, the patient's ONFH did not worsen, the femoral head did not collapse, the joint space was normal, and the hip joint fextion and extension function was acceptable. At last follow-up, the VAS score was 1.9±0.2, and the hip Harris score was 92.1±0.8, both of which were significantly improved when compared with preoperative ones ( t=14.85, P=0.00; t=23.22, P=0.00). CONCLUSION: For patients with ONFH who need musculoskeletal flap transplantation, preoperative DSA of femoral head can determine the location of vascular lesions of femoral head, so as to guide the selection of musculoskeletal flap transplantation, which is of great significance for hip-conserving surgery.

Analysis of percutaneous kyphoplasty or short-segmental fixation combined with vertebroplasty in the treatment of Kummell disease.

BACKGROUND: In recent years, short segment internal fixation combined with vertebroplasty (SSF + VP) has provided a new option for the treatment of Kummell disease (KD). The purpose of this study is to evaluate the efficacy of percutaneous kyphoplasty (PKP) and SSF + VP, to provide evidence-based medical support for the decision-making process when treating KD patients without neurological deficits. METHODS: Databases including MEDLINE (PubMed) and EMBASE (Ovid) (1947 to April 6, 2019) were searched for PKP and short-segmental fixation combined with vertebroplasty (SSF + VP) to treat Kummell disease in randomized controlled trials (RCTs) or cohort studies. Two investigators independently evaluated the eligibility of the studies retrieved from the databases based on the predetermined selection criteria. The postoperative evaluation indexes included operation time, bleeding volume, visual analog scale (VAS) score, Oswestry Disability Index (ODI) score, local vertebral Cobb angle, and cement leakage. When the data were significant, a random-effects model was used for analysis. In contrast, when the results showed no statistical heterogeneity, a fixed-effects model was used to estimate the overall effect sizes. RESULTS: Three retrospective case-control studies were included in the final analysis. The differences in the bleeding volume and operation time were statistically significant, and the combined weighted mean differences (WMDs) (95% CI) were - 0.204.46 (- 210.97, - 197.93) and - 98.98 (- 141.63, 56.32), respectively. The combined data showed that the differences in VAS score, ODI score, local vertebral Cobb angle, and cement leakage were not statistically significant. CONCLUSIONS: This analysis demonstrates that the PKP and SSF + VP methods are safe and effective in treating Kummell disease patients without neurological symptoms. However, PKP can shorten the operation time and reduce the volume of blood loss.

Surgical removal and controlled trypsinization of the outer annulus fibrosus improves the bioactivity of the nucleus pulposus in a disc bioreactor culture.

BACKGROUND: The maintenance of nucleus pulposus (NP) viability in vitro is difficult. The annulus fibrosus (AF) pathway reflects one nutrient transport channel and may have an important effect on NP viability in disc organ cultures. The present study describes a feasible disc pre-treatment involving the AF and investigates its efficacy in improving NP bioactivity in an in vitro disc bioreactor culture. METHODS: Rabbit discs that were randomly assigned to the experimental group (EG) were pretreated via the surgical removal and controlled trypsinization of the outer AF. The discs in the control group (CG) did not receive any special treatment. All discs were organ-cultured in a self-developed bioreactor. Solute transport into the central NP was measured using a methylene blue solution. On days 7 and 14, histological properties, cell viability, cell membrane damage, gene expression and matrix composition within the NP in these two groups were compared with each other and with the corresponding parameters of fresh NP samples. Additionally, the structures of the outer AF and the cartilage endplate (CEP) following pre-treatment were also assessed. RESULTS: The outer AF in the EG became disorganized, but no specific changes occurred in the CEP or the inner AF following pre-treatment. The discs in the EG exhibited increased penetration of methylene blue into the central NP. On days 7 and 14, the NP bioactivity in the EG was improved compared with that of the CG in terms of cell viability, cell membrane damage, gene expression profile and matrix synthesis. Moreover, cell viability and matrix synthesis parameters in the EG were more similar to those of fresh samples than they were to the same parameters in the CG on day 14. CONCLUSIONS: Using this disc pre-treatment, i.e., the surgical removal and controlled trypsinization of the outer AF, NP bioactivity was better maintained for up to 14 days in an in vitro disc bioreactor culture.