A finite element analysis of the carpal arch with various locations of carpal tunnel release.

Objective: The purpose of this study was to investigate the effects of the location of transverse carpal ligament (TCL) transection on the biomechanical property of the carpal arch structure. It was hypothesized that carpal tunnel release would lead to an increase of the carpal arch compliance (CAC) in a location-dependent manner. Methods: A pseudo-3D finite element model of the volar carpal arch at the distal carpal tunnel was used to simulate arch area change under different intratunnel pressures (0-72 mmHg) after TCL transection at different locations along the transverse direction of the TCL. Results: The CAC of the intact carpal arch was 0.092 mm2/mmHg, and the simulated transections ranging from 8 mm ulnarly to 8 mm radially from the center point of the TCL led to increased CACs that were 2.6-3.7 times of that of the intact carpal arch. The CACs after radial transections were greater than those ulnarly transected carpal arches. Conclusion: The TCL transection in the radial region was biomechanically favorable in reducing carpal tunnel constraint for median nerve decompression.

A Retrospective Comparative Study of Endoscopic Treatment of Gastrocnemius Contracture using the Modified Soft Tissue Release Kit.

Background and Objectives: This study aimed to evaluate the effectiveness and safety of endoscopic gastrocnemius recession using the self-developed Modified Soft Tissue Release Kit. Materials and Methods: This retrospective review followed up 22 patients (34 feet) who underwent endoscopic surgery and 20 patients (30 feet) who received open surgery between January 2020 and January 2022. The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the maximum ankle dorsiflexion angle were evaluated preoperatively and at the last follow-up. Postoperative complications were recorded. Patient satisfaction was surveyed at the last follow-up. The comparison between quantitative data was analyzed with the Wilcoxon signed-rank test. The comparison between qualitative data was analyzed with the chi-square test. Results: There was no significant difference in the baseline characteristics between the two groups. The AOFAS score in the endoscopic group increased from 50 (18) points preoperatively to 90 (13) points at the last follow-up; the maximum ankle dorsiflexion angle increased from -7.7 (2.8) degrees to 10.6 (3.6) degrees. The AOFAS score in the open group improved from 47 (15) points preoperatively to 90 (18) points at the last follow-up; the maximum ankle dorsiflexion angle increased from -7.6 (4.0) degrees to 10.7 (3.3) degrees. The change values of the AOFAS scores in the endoscopic and open groups were 39 (15) and 40.5 (11) points, respectively, and there was no significant difference between them. The change values of the maximum ankle dorsiflexion angles in the endoscopic and open groups were 19.5 (4.3) and 19.1 (4.9) degrees, respectively, and there was no significant difference between them. There were no complications, such as sural nerve injury, in both groups. There was no significant difference between the two groups in satisfaction with the surgical outcome. Conclusions: Endoscopic gastrocnemius recession using the Modified Soft Tissue Release Kit can significantly improve the foot function with significant mid-term efficacy and high safety.

A Retrospective Clinical Study of Endoscopic Treatment of Carpal Tunnel Syndrome using the Modified Soft Tissue Release kit.

OBJECTIVE: Carpal tunnel syndrome (CTS) is the most common peripheral entrapment neuropathy, and endoscopic carpal tunnel release (ECTR) is one of the minimally invasive procedures for the treatment of CTS. Based on the shortcomings of ECTR, we designed the "Modified Soft Tissue Release Kit" to assist the endoscopic operation. This study aimed to evaluate the effectiveness and safety of endoscopic treatment of CTS using this kit. METHODS: This retrospective review included 57 patients (86 wrists) who underwent ECTR using the "Modified Soft Tissue Release Kit" at our department between January 2017 and August 2019. Three scale scores (i.e., Quick-Disabilities of the Arm, Shoulder, and Hand [QDASH]; Boston Carpal Tunnel Syndrome Questionnaire [BCTSQ]: symptom severity [BCTSQ-SS] and functional status [BCTSQ-FS]) were recorded to assess hand function and symptoms preoperatively, 1 month postoperatively, 3 months postoperatively, and at the last follow-up. We also asked patients to answer a satisfaction question during follow-up. Pre- and post-operation scores were compared using paired Wilcoxon signed-rank test. Spearman's rank-order correlation was used to evaluate the relationship between scale scores and patient satisfaction. RESULTS: A total of 55 patients (83 wrists) were followed up, with an average follow-up of 27.2 ± 9.3 months. The median preoperative QDASH score was 45.5; the scores at 1 month postoperatively, 3 months postoperatively, and the last follow-up were 4.5, 0, and 0, respectively, with a significant decrease noted compared with the preoperative scores (P < 0.001). The median preoperative BCTSQ-SS and BCTSQ-FS scores were 3.3 and 2.8, respectively; the scores at 1 month postoperatively, 3 months postoperatively, and the last follow-up were 1.2, 1.0, and 1.0, and 1.1, 1.0, and 1.0, respectively, all of which decreased significantly compared with the preoperative scores (P < 0.001). The incidence of nerve injury was 0. The incidence of pillar pain was 0 at the last follow-up. One patient showed no improvement in hand symptoms and function postoperatively, and two patients showed long-term recurrence despite postoperative symptom remission. Approximately 94.5% (52/55) of the patients were satisfied or very satisfied with the outcome. CONCLUSIONS: ECTR with the "Modified Soft Tissue Release Kit" can significantly relieve symptoms and improve function in patients with CTS, with significant short- and mid-term efficacy and high safety.

Outcomes of V-cut Osteotomy on the First Metatarsal Head Combined with Fixation in Mortise-shaped Bone Groove-Plasty and Akin Osteotomy on the First Toe for Hallux Valgus Correction.

OBJECTIVE: Hallux valgus (HV) is a common foot deformity, and recurrence is one of the most serious complications after HV correction. As a result, the surgical technique with a lower recurrence rate is a dream. The purpose of the article should be to observe the correction effect of hallux valgus using a novel "V-cut" osteotomy on the first metatarsal head combined with fixation in mortise-shaped bone groove-plasty technique. METHODS: Twenty-three consecutive patients (40 feet) with HV were included from March 2019 to May 2020, who were all treated using single screw fixation with V-cut osteotomy on the first metatarsal head combined with mortise-shaped metatarsal bone groove-plasty and Akin osteotomy on the first toe for hallux valgus correction. With a mean follow-up time of 21.7 months, the visual analogue scale (VAS) score and American Orthopedic Foot and Ankle Society (AOFAS) forefoot score and the changes of the hallux valgus angle (HVA), intermetatarsal angle (IMA) and distal metatarsal articular angle (DMAA) were evaluated during the clinical follow-up. The paired t test was used for analytical statistics. RESULTS: The VAS score improved from 6.78 ± 1.74 to 1.87 ± 1.45 and the AOFAS score improved from 53.9 ± 12.3 preoperatively to 94.7 ± 6.8 in the latest follow-up postoperatively (P < 0.01). Besides, the HVA improved from 30.0 ± 6.1° to 5.7 ± 2.8° (P < 0.01); the IMA changed from 13.1 ± 2.8° into 3.3 ± 1.6° (P < 0.01); and the DMAA ameliorated from 27.0 ± 8.4° to 5.9 ± 3.5° (P < 0.01). Only five toes had slight numbness and stiffness in early postoperative period, and these symptoms disappeared completely at 6 months after the surgery. Only one foot was corrected to excess. One screw stern protruding beneath the skin happened, which needed secondary screw removal under local anesthesia. CONCLUSIONS: Single screw fixation with V-cut osteotomy on the first metatarsal head combined with fixation in mortise-shaped metatarsal bone groove-plasty and Akin osteotomy on the first toe is an effective way with low recurrence rate for HV correction.

3D-Printed ß-Tricalcium Phosphate Scaffolds Promote Osteogenic Differentiation of Bone Marrow-Deprived Mesenchymal Stem Cells in an N6-methyladenosine-Dependent Manner.

Bone defect is a serious orthopedic disease which has been studied for a long time. Alternative degradable biomaterials are required for bone repairing and regeneration to address the limitation of autogenous bone. ß-tricalcium phosphate (ß-TCP) is an alternative material with good cytocompatibility and has been used in bone defect treatment. However, whether ß-TCP contributes to osteogenesis of bone marrow stem cells (BMSCs) through N6-methyladenosine (m6A) modification remains unknown. To address this issue, we verified the effects of ß-TCP on osteogenesis of BMSCs. We also studied the expression of m6A-related enzymes in BMSCs after ß-TCP treatment. Furthermore, the m6A level and stability of Runt-related transcription factor 2 (RUNX2) mRNA were investigated after ß-TCP treatment. Finally, rat calvarial defect models were performed to detect expression level of osteogenic factors and m6A-related enzymes after the stimulation of three-dimension (3D)-printed ß-TCP scaffolds. We found that ß-TCP showed good biocompatibility and was osteoinductive. Meanwhile, methyltransferase-like 3 (METTL3) increased, causing the elevation of m6A level of RUNX2, results in stabler RUNX2 mRNA level. At last, based on the animal experiments, we demonstrated that the increase of RUNX2 and METTL3 levels was induced by ß-TCP. These findings suggest that METTL3 increases the m6A level of RUNX2 mRNA after ß-TCP induction, contributing to its stability, and the results in vivo also confirmed the osteogenic and bone-repair properties of ß-TCP.

A clinical study on bone defect reconstruction and functional recovery in benign bone tumors of the lower extremity, treated by bone marrow mesenchymal stem cell rapid screening-enrichment-composite system.

BACKGROUND: With the development of medical technology, credible options for defect reconstructions after the resection of benign bone tumors of the lower extremities have become a high priority. As the current reconstructive methods commonly used in clinical practice have some flaws, new methods of reconstruction need to be explored. We aimed to prepare a new kind of bioactive scaffold for the repair of bone defects through a stem cell rapid screening-enrichment-composite technology system developed by our team. Furthermore, we aimed to investigate the curative effects of these bioactive scaffolds. METHODS: Firstly, cell count, trypan blue exclusion rate, and ALP staining were used to evaluate changes in enrichment efficiency, cell activity, and osteogenic ability before and after enrichment. Then, the scaffolds were placed under the skin of nude mice to verify their osteogenic effects in vivo. Finally, the scaffolds were used for the reconstruction of bone defects after operations for benign bone tumors in a patient's lower limb. The healing status of the defect site at 1 and 3 months was assessed by X-ray, and the Musculoskeletal Tumor Society (MSTS) score was applied to reflect the recovery of patient limb function. RESULTS: The system effectively enriched stem cells without affecting the activity and osteogenic abilities of the bone marrow mesenchymal stem cells (BMSCs). Meanwhile, the bioactive scaffolds obtained better osteogenic effects. In patients, the active scaffolds showed better bone integration and healing status, and the patients also obtained higher MSTS scores at 1 and 3 months after surgery. CONCLUSION: As a new technique, the rapid screening-enrichment-composite technology of stem cells demonstrates a better therapeutic effect in the reconstruction of bone defects after surgery for benign bone tumors of the lower extremities, which will further improve patient prognosis.

Varisized 3D-Printed Lunate for Kienböck's Disease in Different Stages: Preliminary Results.

OBJECTIVE: To evaluate the feasibility of arthroplasty with varisized three-dimensional(3D) printing lunate prosthesis for the treatment of advanced Kienböck's disease (KD). METHODS: From 2016 November to 2018 September, a retrospective study was performed for the patients of KD in our hospital. Five patients (two males, three females) were included in this study. The mean age of the patients at the time of surgery was 51.6 years (range, 37-64 years). Varisized prosthesis identical to the live model in a ratio of 1:0.85, 1:1, and 1:1.1 were fabricated by 3D printing. All patients (one in Lichtman IIIA stage, two in Lichtman IIIB stage, one in Lichtman IIIC stage, and one in Lichtman IV stage) were treated with lunate excision and 3D printing prosthetic arthroplasty. Visual analog scale score (VAS), the active movement of wrist (extension, flexion) and strength were assessed preoperatively and postoperatively. The Mayo Modified Wrist Score (MMWS), Disabilities of the Arm, Shoulder and Hand (DASH) Score, and patient's satisfaction were evaluated during the follow-up. RESULTS: Prosthesis identical to the live model in a ratio of 1:0.85 or 1:1 were chosen for arthroplasty. The mean operation time (range, 45 to 56 min) was 51.8 ± 4.44 min. Follow-up time ranged from 11 months to 33 months with the mean value of 19.4 months. The mean extension range of the wrist significantly increased from preoperative 44° ± 9.6° to postoperative 60° ± 3.5° (P < 0.05). The mean flexion range of the wrist significantly increased from preoperative 40° ± 10.6° to postoperative 51° ± 6.5° (P < 0.05). The active movement of wrist and strength were improved significantly in all patients. VAS was significantly reduced from 7.3 preoperatively to 0.2 at the follow-up visit (P < 0.05). The mean DASH score was 10 (range, 7.2-14.2), and the mean MMWS was 79 (range, 70-90). There were no incision infection. All patients were satisfied with the treatment. CONCLUSIONS: For patients suffering advanced Kienböck's disease, lunate excision followed by 3D printing prosthetic arthroplasty can reconstruct the anatomical structure of the carpal tunnel, alleviate pain, and improve wrist movement.

IL-23, but not IL-12, plays a critical role in inflammation-mediated bone disorders.

Interleukin-12 (IL-12) and IL-23 are thought to have central roles in inflammation and are critical to pathologies associated with inflammation-induced bone disorders. The deletion of IL-12p40 (a common subunit of IL-12 and IL-23) can improve bone regeneration. However, the relative roles of IL-12 and IL-23 in bone disorders are largely unknown. Methods: Ectopic bone formation and skull defect models were established to evaluate the relative roles of IL-12 and IL-23 in inflammatory bone disorders. Differences in bone mass among WT, IL-12p35-/-, and IL-12p40-/- mice (young and elderly) were detected by micro-CT. Osteogenic and osteoclastic activities were explored using ELISA, qRT-PCR, and histological analysis. Moreover, the mechanisms by which IL-12 and IL-23 regulated the differentiation of BMMSCs and RAW264.7 cells were explored using Alizarin Red and tartrate-resistant acid phosphatase staining in vitro. Apilimod was used to inhibit IL-12 and IL-23 production in vivo. Results: Mice deficient in IL-12p40 promoted bone formation and protected against aging-related bone loss. By contrast, bone loss was aggravated in IL-12-/- mice, suggesting that IL-23 may play a dominant role in inflammation-related bone disorders. Mechanistically, IL-12 and IL-23 coupled osteogenesis and osteoclastic activities to regulate bone homeostasis and repair. IL-23 deficiency increased bone formation and inhibited bone resorption. Finally, apilimod treatment significantly improved bone regeneration and calvarial defect repair. Conclusion: These data collectively uncover a previously unrecognized role of IL-23 in skeletal tissue engineering. Thus, IL-23 can act as a biomarker to predict diseases and treatment efficacy, and apilimod can be used as an effective therapeutic drug to combat inflammatory bone disorders.

Huge aneurysmal bone cyst secondary to giant cell tumor of the hand phalanx: a case report and related literature.

BACKGROUND: Aneurysmal bone cyst (ABC) secondary to Giant Cell Tumor of bone (GCT) is a rare lesion, of which the incidence is about 0.011 to 0.053 per 100,000 every year. There are only a few previous case reports, and most of them occur in the spine, long bones or flat bones. CASE PRESENTATION: We report one case of a patient who complained of "progressive enlargement of the mass on right-hand fifth finger for 5 years with ulceration for 6 months". After the imaging examination in our hospital, it was diagnosed as a "huge bone tumor on the proximal phalanx of the right-hand fifth finger", then wide excision and amputation of the fifth finger were made. The pathological examination diagnosed the mass as aneurysmal bone cyst secondary to giant cell tumor, 13 × 8 × 6 cm3, with no local infiltration observed. No recurrence and metastasis occurred 18 months after the operation, and the patient recovered well. CONCLUSION: In this report, we discuss the etiology, diagnosis, differentiation, and management of Aneurysmal bone Cyst secondary to Giant Cell Tumor of bone, and review previous case studies.

[Progress on cell-mediated degradation of bone materials].

Biomaterials have been widely used as bone grafts for bone tissue repair. The application of biomaterials needs to consider various aspects of material properties such as biocompatibility, mechanical strength and plasticity. It is also necessary for bone repair to consider the degradability of materials. Previous studies have shown that biomaterials can be degraded by physical, chemical and biological ways. Cell-mediated degradation is an important part of the biodegradation process of , mainly carried out by the biological behavior of macrophages and osteoclasts and reactive oxygen species, enzymes and acidic metabolites secreted by them. Illustration of cell-mediated degradation of biological materials helps us understand the biological behavior of cells better, to accurately design and manufacture more effective bone repair materials, which is conducive to initial stability during material implantation, in line with the consistence of material degradation and new bone formation, promoting bone regeneration and bone repair.

High-Dose TGF-ß1 Impairs Mesenchymal Stem Cell-Mediated Bone Regeneration via Bmp2 Inhibition.

Transforming growth factor-ß1 (TGF-ß1) is a key factor in bone reconstruction. However, its pathophysiological role in non-union and bone repair remains unclear. Here we demonstrated that TGF-ß1 was highly expressed in both C57BL/6 mice where new bone formation was impaired after autologous bone marrow mesenchymal stem cell (BMMSC) implantation in non-union patients. High doses of TGF-ß1 inhibited BMMSC osteogenesis and attenuated bone regeneration in vivo. Furthermore, different TGF-ß1 levels exhibited opposite effects on osteogenic differentiation and bone healing. Mechanistically, low TGF-ß1 doses activated smad3, promoted their binding to bone morphogenetic protein 2 (Bmp2) promoter, and upregulated Bmp2 expression in BMMSCs. By contrast, Bmp2 transcription was inhibited by changing smad3 binding sites on its promoter at high TGF-ß1 levels. In addition, high TGF-ß1 doses increased tomoregulin-1 (Tmeff1) levels, resulting in the repression of Bmp2 and bone formation in mice. Treatment with the TGF-ß1 inhibitor SB431542 significantly rescued BMMSC osteogenesis and accelerated bone regeneration. Our study suggests that high-dose TGF-ß1 dampens BMMSC-mediated bone regeneration by activating canonical TGF-ß/smad3 signaling and inhibiting Bmp2 via direct and indirect mechanisms. These data collectively show a previously unrecognized mechanism of TGF-ß1 in bone repair, and TGF-ß1 is an effective therapeutic target for treating bone regeneration disability. © 2019 American Society for Bone and Mineral Research.

Comparison and characterization of enriched mesenchymal stem cells obtained by the repeated filtration of autologous bone marrow through porous biomaterials.

BACKGROUND: When bone marrow is repeatedly filtered through porous material, the mesenchymal stem cells (MSCs) in the bone marrow can adhere to the outer and inner walls of the carrier material to become enriched locally, and this is a promising method for MSC enrichment. In this process, the enrichment efficiency of MSCs involved in the regulation of the cell ecology of postfiltration composites containing other bone marrow components is affected by many factors. This study compared the enrichment efficiency and characterized the phenotypes of enriched MSCs obtained by the filtration of autologous bone marrow through different porous bone substitutes. METHODS: Human bone marrow was filtered through representative porous materials, and different factors affecting MSC enrichment efficiency were evaluated. The soluble proteins and MSC phenotypes in the bone marrow before and after filtration were also compared. RESULTS: The enrichment efficiency of the MSCs found in gelatin sponges was 96.1% ± 3.4%, which was higher than that of MSCs found in allogeneic bone (72.5% ± 7.6%) and porous ß-TCP particles (61.4% ± 5.4%). A filtration frequency of 5-6 and a bone marrow/material volume ratio of 2 achieved the best enrichment efficiency for MSCs. A high-throughput antibody microarray indicated that the soluble proteins were mostly filtered out and remained in the flow through fluid, whereas a small number of proteins were abundantly (> 50%) enriched in the biomaterial. In terms of the phenotypic characteristics of the MSCs, including the cell aspect ratio, osteogenetic fate, specific antigens, gene expression profile, cell cycle stage, and apoptosis rate, no significant changes were found before or after filtration. CONCLUSION: When autologous bone marrow is rapidly filtered through porous bone substitutes, the optimal enrichment efficiency of MSCs can be attained by the rational selection of the type of carrier material, the bone marrow/carrier material volume ratio, and the filtration frequency. The enrichment of bone marrow MSCs occurs during filtration, during which the soluble proteins in the bone marrow are also absorbed to a certain extent. This filtration enrichment technique does not affect the phenotype of the MSCs and thus may provide a safe alternative method for MSC enrichment.

Screen-enrich-combine circulating system to prepare MSC/ß-TCP for bone repair in fractures with depressed tibial plateau.

Aim: To evaluate the clinical efficacy of mesenchymal stem cell/ß-tricalcium phosphate composites (MSC/ß-TCP) prepared with a screen-enrich-combine circulating system (SECCS) in patients with depressed tibial plateau fractures. Materials & methods: Bone defects in depressed tibial plateaus were filled with MSC/ß-TCP (n = 16) or with ß-TCP only (n = 23). Enrichment efficiency and effect of enrichment on cell viability were evaluated. Clinical results were assessed by imaging examination and Lysholm score. Results: SECCS effectively integrated MSCs with ß-TCP. At 18 months postimplantation, new bone ratio was significantly higher in patients treated with MSC/ß-TCP than in those treated with ß-TCP only (p = 0.000). Patients with MSC/ß-TCP implants had better functional recovery (p = 0.028). Conclusion: MSC/ß-TCP prepared by SECCS were effective in the treatment of bone defects in patients with depressed tibial plateau fractures, promoted bone regeneration and improved joint function recovery.

Bone Mesenchymal Stem Cell-Enriched ß-Tricalcium Phosphate Scaffold Processed by the Screen-Enrich-Combine Circulating System Promotes Regeneration of Diaphyseal Bone Non-Union.

Bone non-union after fracture, considered a therapeutic challenge for orthopedics, always needs a reversion surgery, including autograft transplantation (AGT). However, adverse events related to autograft harvest cannot be ignored. Our group designed a novel system called the bone marrow stem cell Screen-Enrich-Combine Circulating System (SECCS) by seeding mesenchymal stem cells (MSCs) into ß-tricalcium phosphate (ß-TCP) during surgery to thereafter rapidly process bioactive bone implantation. In this retrospective case-control study, 30 non-union patients who accepted SECCS therapy and 20 non-union patients who accepted AGT were enrolled. By SECCS therapy, the MSC-enriched ß-TCP particles were implanted into the non-union gap. During the enrichment procedure, a significant proportion of MSCs were screened and enriched from bone marrow into porous ß-TCP particles, and the cells possessed the capacity for three-line differentiation and were CD90+/CD105+/CD34-/CD45-. Approximately 82.0±10.7% of MSCs were enriched from 60 mL bone marrow without damaging cell viability, and approximately 11,444.0±6,018 MSCs were transplanted per patient. No implant-related infections occurred in any case. After 9 months of follow-up, 27 patients (90%) in the SECCS group acquired clinical union, compared with 18 patients (90%) in the AGT group (clinical union time, P = 0.064), and postoperative radiographic union score at 9 months post-operation was similar between the two groups. In conclusion, the SECCS could concentrate a large proportion of MSCs from bone marrow to acquire enough effective cells for therapy without in vitro cell culture. Bone substitutes processed by SECCS demonstrated encouraging promotion of bone regeneration and showed a satisfactory clinical curative effect for diaphyseal bone non-union, which was non-inferior to AGT.

Molecular pathogenesis of fracture nonunion.

Fracture nonunion, a serious bone fracture complication, remains a challenge in clinical practice. Although the molecular pathogenesis of nonunion remains unclear, a better understanding may provide better approaches for its prevention, diagnosis and treatment at the molecular level. This review tries to summarise the progress made in studies of the pathogenesis of fracture nonunion. We discuss the evidence supporting the concept that the development of nonunion is related to genetic factors. The importance of several cytokines that regulate fracture healing in the pathogenesis of nonunion, such as tumour necrosis factor-α, interleukin-6, bone morphogenetic proteins, insulin-like growth factors, matrix metalloproteinases and vascular endothelial growth factor, has been proven in vitro, in animals and in humans. Nitric oxide and the Wnt signalling pathway also play important roles in the development of nonunion. We present potential strategies for the prevention, diagnosis and treatment of nonunion, and the interaction between genetic alteration and abnormal cytokine expression warrants further investigation. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: A better understanding of nonunion molecular pathogenesis may provide better approaches for its prevention, diagnosis and treatment in clinical practice.

Mesenchymal stem cells and porous ß-tricalcium phosphate composites prepared through stem cell screen-enrich-combine(-biomaterials) circulating system for the repair of critical size bone defects in goat tibia.

BACKGROUND: Efficacious bone substitute is essential for the treatment of a critical size bone defect. Currently, the bone substitutes commonly used in clinical practice lack osteogenic capacity and the therapeutic efficacy is not ideal. Herein, a novel stem cell screen-enrich-combine(-biomaterials) circulating system (SECCS) was introduced to provide the substitutes with osteogenic ability. The stem cell screening, enrichment, and recombination with substitutes could be integrated during the surgical operation. Using SECCS, the bioactive mesenchymal stem cells (MSCs) and porous ß-tricalcium phosphate (ß-TCP) composites (MSCs/ß-TCP) were rapidly prepared for critical size bone defect repair and validated in goat models of critical size tibia defects. METHODS: Twelve goats with right hind limb tibia defects of 30 mm were randomly divided into two groups: six (the experimental group) were treated with MSCs/ß-TCP prepared by SECCS and the other six goats (the control group) were treated with pure porous ß-TCP. The repair effect was assessed by x-ray, computed tomography (CT), micro-CT, histology and histomorphology 6 months after the operation. In addition, the enrichment efficacy of MSCs and the characteristics of the MSCs/ß-TCP prepared by SECCS were evaluated. RESULTS: The SECCS could compound about 81.3 ± 3.0% of the MSCs in bone marrow to the porous ß-TCP without affecting the cell viability. The average number of MSCs for retransplantation was 27,655.0 ± 5011.6 for each goat from the experimental group. In vitro, satisfactory biocompatibility of the MSCs/ß-TCP was performed, with the MSCs spreading adequately, proliferating actively, and retaining the osteogenic potential. In vivo, the defect repair by MSCs/ß-TCP with good medullary cavity recanalization and cortical remodeling was significantly superior to that of pure porous ß-TCP. CONCLUSIONS: The MSCs/ß-TCP prepared through SECCS demonstrated significant therapeutic efficacy in goat models of critical size bone defect. This provides a novel therapeutic strategy for critical size bone defects caused by severe injury, infection, and bone tumor resection with a high profile of safety, effectiveness, simplicity, and ease.

A successful treatment of necrotizing fasciitis following the surgery of distal radius plate removal: A case report and literature review.

RATIONALE: Necrotizing fasciitis (NF) is defined as a rare, rapidly progressive, and highly lethal skin infection characterized by necrosis of the fascia and subcutaneous tissue. PATIENT CONCERNS: The present study aims to discuss the case of a 35-year-old man who developed NF following a routine sterile right distal radius bone plate removal surgery. DIAGNOSES: The patient was suspected of NF based on his clinical manifestations, laboratory tests, and imaging results. The diagnosis of NF was confirmed by histological examinations. INTERVENTIONS: Serial prompt and extensive debridement was performed during the rapid and aggressive extension of the skin infection, together with antibiotics and supportive treatments. OUTCOMES: The condition of the patient finally improved on the sixth day of disease progression. Skin grafting of his right forearm wound was performed successfully 2 months after the admission. LESSONS: NF can occur during the perioperative period for routine clean radius plate removal operation in patients with no risk factor for NF. The objective is to remind the physicians to stay aware of this disease, especially its early clinical signs and symptoms. Urgent subsequent treatment, including surgical debridement, antibiotic therapy, and supporting management, is the key to ensure the survival and better prognosis of patients.

Improving Bone Regeneration Using Chordin siRNA Delivered by pH-Responsive and Non-Toxic Polyspermine Imidazole-4,5-Imine.

BACKGROUND/AIMS: Bone nonunion remains a challenge for orthopaedists. The technological advancements that have been made in precisely silencing target genes have provided promising methods to address this challenge. METHODS: We detected the expression levels of the bone morphogenetic protein (BMP) inhibitors Chordin, Gremlin and Noggin using realtime PCR in bone mesenchymal stem cells (BMSCs) isolated from patients with normal fracture healing and those with bone nonunion. Moreover, we detected the expression of Chordin, Gremlin and Noggin during the osteogenic differentiation of human BMSCs (hBMSCs) using real-time PCR and Western blot. We delivered Chordin siRNA to hBMSCs using a previously reported cationic polymer, polyspermine imidazole-4,5-imine (PSI), as a pH-responsive and non-cytotoxic transfection agent. The apoptosis and cellular uptake efficiency were analysed by flow cytometry. RESULTS: We identified Chordin as the most appropriate potential therapeutic target gene for enhancing the osteogenic differentiation of hBMSCs. Chordin knockdown rescued the osteogenic capacity of hBMSCs isolated from patients with bone nonunion. Highly efficient knockdown of Chordin was achieved in hBMSCs using PSI. Chordin knockdown promoted hBMSC osteogenesis and bone regeneration in vitro and in vivo. CONCLUSIONS: Our results suggest that Chordin is a potential target for improving osteogenesis and bone nonunion therapy and that responsive and non-toxic cationic polyimines such as PSI are therapeutically feasible carriers for the packaging and delivery of Chordin siRNA to hBMSCs.

A novel cytotherapy device for rapid screening, enriching and combining mesenchymal stem cells into a biomaterial for promoting bone regeneration.

Bone defects are a common challenge in clinic, usually warranting bone grafts. However, current strategies to obtain effective graft materials have many drawbacks. Mesenchymal stem cell (MSC)-based therapy is a promising alternative. We designed an innovative appliance named the stem cell screen-enrich-combine(-biomaterials) circulating system (SECCS). In this study, 42 patients who required bone graft underwent SECCS-based treatment. Their bone marrow samples and beta-tricalcium phosphate (ß-TCP) granules were processed in the SECCS for 10-15 minutes, to produce MSC/ß-TCP composites. These composites were grafted back into bone defect sites. The results showed 85.53% ± 7.95% autologous MSCs were successfully screened, enriched, and seeded on the ß-TCP scaffolds synchronously. The cell viability remained unchanged after SECCS processing. Clinically, all patients obtained satisfactory bone healing. Thus, without in vitro culture, the SECCS can produce bioactive MSC/ß-TCP composites for bone regeneration during surgery. The SECCS represents a convenient, rapid, low-cost, and safe method for bone regeneration.

Autologous Stem Cell Transplantation Promotes Mechanical Stretch Induced Skin Regeneration: A Randomized Phase I/II Clinical Trial.

BACKGROUND: Mechanical stretch, in term of skin expansion, can induce effective but limited in vivo skin regeneration for complex skin defect reconstruction. We propose a strategy to obtain regenerated skin by combining autologous stem cell transplantation with mechanical stretch. METHODS: This randomized, blinded placebo-controlled trial enrolled 38 adult patients undergoing skin expansion presenting with signs of exhausted regenerative capacity. Patients randomly received autologous bone marrow mononuclear cell (MNC) or placebo injections intradermally. Follow-up examinations were at 4, 8weeks and 2years. The primary endpoint was the volume achieved in relation to the designed size of the expander (expansion index, EI). Secondary endpoints were surface area, thickness and texture of expanded skin. This trial is registered with ClinicalTrial.gov, NCT01209611. FINDINGS: The MNC group had a significantly higher EI at 4weeks (mean difference 0.59 [95% CI, 0.03-1.16]; p=0.039) and 8weeks (1.05 [95% CI, 0.45-1.66]; p=0.001) versus controls. At 8weeks, the MNC group had significantly thicker skin (epidermis: p<0.001, dermis: p<0.001) and higher subjective scores for skin quality/texture (24.8 [95% CI, 17.6-32.1]; p<0.001). The MNC group had more skin surface area (70.34cm2 [95% CI, 39.75-100.92]; p<0.001). Patients in the MNC group gained up to the quadrupled surface area of expanded skin compared to pre-expansion at the end of expansion. No severe adverse events occurred. INTERPRETATION: Intradermal transplantation of autologous stem cells represents a safe and effective strategy to promote in vivo mechanical stretch induced skin regeneration, which can provide complex skin defect reconstruction with plentiful of tissue.