Objective:To investigate the effects of dual vascularized tissue-engineered bone constructed by vascular bundles and endothelial progenitor cells (EPCs) on repair of large bone defects and vascular regeneration.Methods:EPCs were seeded on the demineralized bone matrix (DBM) scaffolds and cultured for 6 days. The attachment and morphology of EPCs on DBM scaffolds were observed by electron microscopy. Next, the radial artery was implanted into a vascular groove opened inside the DBM-EPCs composite scaffolds. Finally, models of a large segmental bone defect were constructed using the radii from 18 New Zealand white rabbits. The rabbits were randomly divided into 4 groups using a simple random sampling method: DBM group, DBM+EPCs group, DBM+vascular bundle group, and DBM+EPCs+vascular bundle group. The DBM group and DBM+EPCs group shared the same rabbits so that transplantations were conducted into the left and right forearms respectively; the DBM+vascular bundle group and DBM+EPCs+vascular bundle group also shared the same rabbits so that transplantations were conducted into the left and right forearms respectively. Consequently, there were 9 experimental sites in each group. X-ray examination and gross morphological observation were performed to evaluate the bone regeneration in the experimental rabbits in each group at 4, 8, and 12 weeks after surgery, and CD31 immunofluorescence staining was used to evaluate the vascular regeneration. Micro-CT was used to analyze bone tissue parameters and reconstruct the three-dimensional structures of the defects site at 12 weeks after surgery.Results:Compared with the DBM, DBM+EPCs and DBM+vascular bundle groups, the DBM+EPCs+vascular bundle group showed new bone tissue crawling on the scaffold surface at 4 weeks after surgery, almost complete healing of the bone defect area at 8 weeks, and forming of a complete and dense bone bridge and appearance of a bone marrow cavity at 12 weeks. Micro-CT data at 12 weeks after surgery showed regular arrangement of the trabeculae, significantly improved mineralization, and increased thickness of the bone cortex in the DBM+EPCs+vascular bundle group. Additionally, in the DBM+EPCs+vascular bundle group, the number of microvessels was significantly higher than that in the other groups at 4, 8, 12 weeks after surgery ( P<0.05), and the angiogenesis and bone tissue regeneration were particularly prominent at 12 weeks after surgery. The number of CD31 cells in the DBM+EPCs+vascular bundle group increased significantly more than that in the DBM, DBM+EPCs and DBM+vascular bundle groups ( P<0.05). Conclusion:As the dual vascularized tissue-engineered bone constructed by vascular bundles and EPCs can significantly promote bone tissue regeneration and angiogenesis, it may be a potential therapeutic strategy for repair of large bone defects.

Objective:To investigate the effects of dual vascularized tissue-engineered bone constructed by vascular bundles and endothelial progenitor cells (EPCs) on repair of large bone defects and vascular regeneration.Methods:EPCs were seeded on the demineralized bone matrix (DBM) scaffolds and cultured for 6 days. The attachment and morphology of EPCs on DBM scaffolds were observed by electron microscopy. Next, the radial artery was implanted into a vascular groove opened inside the DBM-EPCs composite scaffolds. Finally, models of a large segmental bone defect were constructed using the radii from 18 New Zealand white rabbits. The rabbits were randomly divided into 4 groups using a simple random sampling method: DBM group, DBM+EPCs group, DBM+vascular bundle group, and DBM+EPCs+vascular bundle group. The DBM group and DBM+EPCs group shared the same rabbits so that transplantations were conducted into the left and right forearms respectively; the DBM+vascular bundle group and DBM+EPCs+vascular bundle group also shared the same rabbits so that transplantations were conducted into the left and right forearms respectively. Consequently, there were 9 experimental sites in each group. X-ray examination and gross morphological observation were performed to evaluate the bone regeneration in the experimental rabbits in each group at 4, 8, and 12 weeks after surgery, and CD31 immunofluorescence staining was used to evaluate the vascular regeneration. Micro-CT was used to analyze bone tissue parameters and reconstruct the three-dimensional structures of the defects site at 12 weeks after surgery.Results:Compared with the DBM, DBM+EPCs and DBM+vascular bundle groups, the DBM+EPCs+vascular bundle group showed new bone tissue crawling on the scaffold surface at 4 weeks after surgery, almost complete healing of the bone defect area at 8 weeks, and forming of a complete and dense bone bridge and appearance of a bone marrow cavity at 12 weeks. Micro-CT data at 12 weeks after surgery showed regular arrangement of the trabeculae, significantly improved mineralization, and increased thickness of the bone cortex in the DBM+EPCs+vascular bundle group. Additionally, in the DBM+EPCs+vascular bundle group, the number of microvessels was significantly higher than that in the other groups at 4, 8, 12 weeks after surgery ( P<0.05), and the angiogenesis and bone tissue regeneration were particularly prominent at 12 weeks after surgery. The number of CD31 cells in the DBM+EPCs+vascular bundle group increased significantly more than that in the DBM, DBM+EPCs and DBM+vascular bundle groups ( P<0.05). Conclusion:As the dual vascularized tissue-engineered bone constructed by vascular bundles and EPCs can significantly promote bone tissue regeneration and angiogenesis, it may be a potential therapeutic strategy for repair of large bone defects.

Objective:To compare the mechanical properties between our self-designed axially controlled compression spinal rod (ACCSR) and conventional spinal rod (CSR) for lumbar spondylolysis (LS).Methods:This study selected 36 ACCSRs (the ACCSR group) and 36 CSRs (the CSR group), both of which were in a diameter of 6.0 mm and manufactured in the same batch. They were subjected respectively to biomechanical tests of spinal rod and pedicle screw-rod internal fixation system. In spinal rod tests: the stiffness and yield load of the spinal rods were calculated using four-point bending tests ( n=7) and comparisons were made between the 2 groups; spinal rod fatigue tests ( n=8) recorded the successful compression loads after 2.5 million cycles of loading and compared them with the maximum force at the isthmus of a normal adult's unilateral lumbar spine (198.72 N). In tests of the pedicle screw-rod internal fixation system, the axial compression tests ( n=7) measured the axial gripping capacity, the axial torsion tests ( n=7) the torsional gripping capacity, and the lateral compression tests ( n=7) the stiffness and yield load of pedicle screws in the 2 groups respectively. Results:The stiffness [(1,543.37±61.41) N/mm] and yield load [1,338.57 (1,282.00, 1,353.80) N] of ACCSR group were significantly smaller than those of CSR group [(3,797.63±156.15) N/mm and 4,059.95 (3,813.80, 4,090.89) N] ( P<0.05). The spinal rod fatigue tests showed that the respective loads of CSR and ACCSR passing the 2.5 million fatigue tests were 640.00 N and 320.00 N, both larger than the maximum force at the unilateral lumbar isthmus of a normal adult (198.72 N). There were no significant differences between the ACCSR group and the CSR group in the axial gripping capacity and torsional gripping capacity, as well as in stiffness and yield load of screws between the 2 groups ( P>0.05). Conclusions:In fixation of LS, although the yield load, stiffness and fatigue resistance of ACCSR are inferior to those of CSR, the biomechanical properties of the two sets of pedicle screw-rod internal fixation system are comparable. The fatigue resistance of ACCSR can meet the stress requirements of the normal human isthmus.

Tissue engineering bone technology, grounded in seed cells, cytokines, and scaffold supports, provides an effective solution for addressing extensive bone defects, demonstrating significant potentials in the field of bone repair. However, this technology still faces numerous challenges. Focusing on vascularization in engineered bones, this article reviews various methods to enhance vascularization within tissue-engineered bones, including multicellular co-culture, application of angiogenic factors, advanced 3D printing, and aid of surgical interventions. This article also analyses the latest research developments and the limitations of the methods, and speculates future research directions for tissue engineered bone.

Limb (digit) replantation is the primary treatment in salvage of severed traumatic limbs (digits). It is vital to improve the success rate of limb (digit) salvage and the function recovery. Once a human limb (digit) is separated from the body, blood circulation stops and normal physiological metabolism are disrupted, hence result in a series of physiological and pathological changes such as cell degeneration and tissue necrosis, which greatly affect the therapeutic effect of limb (digit) replantation. Therefore, how to scientifically minimise the metabolism of tissues in a severed limb (digit) and mitigate the subsequent ischaemia-reperfusion injury to improve the success rate of limb (digit) replantation is a hot issue in the field of limb (digit) replantation. In this article, a review of current status and progress of existing limb (digit) preservation methods are presented. Through an extensive search and analysis of literatures, the advantages and disadvantages of current limb (digit) preservation methods are summarised in the hope that it will provide a reference for clinical preservation of severed limbs (digit) .

Surgical robots, as a new means for surgeons, have been gradually applied in orthopedics. Initially, the development of orthopedic robots was stagnant for a long time because of limited techniques available, clumsy equipment, high costs, and low market demands. The recent decade has witnessed rapid growth of artificial intelligence in all walks of life, increasing investment in research and development, reducing manufacture costs and expanding demands for precise and individualized medical treatment so that a wide variety of novel and ingenious robotic systems have been proposed, prototyped, and commercialized in most of the major procedures in orthopedic surgery, including knee and hip replacements, cruciate ligaments surgery, spine surgery, corrective osteotomy, bone tumor surgery, and trauma surgery. This review depicts the history of development and future prospects in application of surgical robots in the field of orthopedics.

Objective To discuss the clinical value of benefiting Qi and activating blood circulation on crit-ical limb ischemia(CLI)of lower extremity arteriosclerosis obliterans(ASO)after intervention. Methods Totally 43 patients with CLI were randomly divided into treatment group and control group. Patients in control group re-ceived basic treatment and interventional therapy,and those in treatment group additional benefiting Qi and activat-ing blood circulation for 6 months.The ankle brachial index(ABI),clinical symptoms and patency rate of vascular in 1 month,3 months and 6 months after angioplasty were analyzed and compared. Results ABI in treatment group 1 month,3 months and 6 months after angioplasty was increased when compared with that in control group (P<0.05),and the incidence rate of claudication and rest pain was significantly lower than that in control group 3 months and 6 months later(P<0.05).The patency rate of vessels in treatment group was higher than that of con-trol group and there was significant difference between the two groups(P < 0.05). Conclusions Benefiting Qi to activating blood circulation could improve the clinical efficacy and reduce the degree of restenosis in patients with CLI.

Objective To assess preliminary clinical efficacy of digital assisted technology in double skin paddle anterolateral thigh flap reconstructing degloved injury of forefoot or midfoot.Methods From March 2013 to December 2015,eight patients with degloved injury of forefoot or midfoot were retrospectively analyzed by case series study.They were seven males and one female,with age range of 18-51 years (mean,34.5 years).The foot skin defect area ranged from 18 cm × 12 cm to 13 cm × 10 cm.All patients underwent computed tomography angiography (CTA) in lower extremities preoperatively.The CTA data were entered into Mimics 15.0 software in DICOM format.Based on perforating condition of descending branch of lateral fenoral circunflex artery and the size of foot defect,one thigh was chosen for three dimensional reconstruction of anterolateral thigh flap.The flap size ranged from 24 cm× 9 cm to 19 cm × 7 cm.All reconstructive surgeries were performed secondarily.Patients were all at Ⅱ stage recovery.The survival of flaps and healing status of flap donor sites were observed in one month after surgery.The number of debulking flaps was recorded.The appearance of flaps,shoe wearing,gait and related complications were recorded.Results The follow-up was 10-21 months (mean,15.5 months.All flaps survived uneventfully,and all donor sites were sutured directly.Three patients had twice debulking procedures,three patients had one debulking procedure,and two patients had no debulking.At the last visit in follow-up,the color and texture of flaps were good.All patients were able to wear shoes normally,two patients remained mild abnormal gait,and one patient presented superficial ulcer at the medial of the forefoot.Conclusions Double skin paddle anterolateral thigh flap for reconstruction of degloved injury of forefoot or midfoot can prompt wound healing and decrease complications.Digital assisted technology is an excellent supplementary method in double skin paddle anterolateral thigh flap for reconstruction of degloved injury of foot,which makes precise preoperative planning and intraoperative accurate cutting.

Objective To evaluate the curative effect of interventional therapy in treating arteriosclerosis obliterans (ASO),and to discuss the related factors that may affect the postoperative recurrence.Methods The clinical data of 137 patients with lower extremity ASO (184 affected limbs in total),who were treated with interventional management during the period from January 2011 to October 2014,were retrospectively analyzed.After the treatment,the patients were followed up for 18 months.The arterial patency was checked up periodically,and the related factors that might induce recurrence were analyzed.Results The technical success rates for diseased iliac artery,femoral popliteal artery and infrapopliteal artery were 97.4％,92.5％ and 88.6％ respectively,while the technical success rates for TASC Ⅱ A,B,C and D type lesions were 97.4％,96.1％,89.7％ and 87.0％ respectively.Follow-up check-ups showed that the arterial patency rate of infrapopliteal artery was lower than that of iliac femoral artery and popliteal artery (P＜0.05),the restenosis rate of TASC Ⅱ C and D type lesions was higher than that of TASC Ⅱ A and B type lesions (P＜0.05).Multivariate Cox regression analysis indicated that diabetes mellitus,smoking and hyperlipidemia were the independent risk factors that could affect postoperative recurrence.Conclusion For the treatment of lower extremity ASO,interventional therapy is safe and effective.The postoperative restenosis rate is related to the location and type of the diseased arteries.Effective control of blood sugar level,smoking cessation and lipid-lowering measures can help reducc thc incidence of postoperative recurrence.

Objective Retrospectively investigate the application of anterolateral thigh flow-through flap in reconstruction of the extremities,to estimate its role and characteriscts.Methods From March,2010 to January,2016,anterolateral thigh flow-through flap was performed for reconstruction of the extremities in 87 patients (56 males,and 31 females).Patient ages ranged from 13 to 68 years,average of 34.4 years.Of all cases,there were 37 legs,21 ankles or foots,1 arm,19 forearms,and 9 hands.The role and result of anterolateral thigh flow-through flap was analyzed retrospectively.Results The result showed that when anterolateral thigh flow-through flap was transferred,which simutaneously played various roles as follows:①rebuilding main vascular defect,to revascularise the distal limb.② preserving recipient vessels,to prevent flow impaired.③rebulding recepient vessel defect.④ protecting vascular anastomosis and preserving recipient flow simultaneously.⑤avoiding the dilemma of end-to-side anastomosis when recipient vessels is deep.⑥ balancing blood flow,the blood supply of the flap was more stable.⑦ linking another tissue in a series fashion,to achieve complex reconstruction.Vascular compromise occurred in 3 cases after surgery,total necrosis occurred in 1 case and partial necrosis in 1 case after reexploration.One case presented deep infection and secondary with renal failure,and received amputation.Local infection presented in 3 cases,wound dehiscence in 2 cases.All the other flaps survivled uneventfully,and its texture and color was normal.In donor site,local infection occurred in 1 case,wound dehiscence in 2 cases.Conclusion Anterolateral thigh flow-through flap has function of many sided reconstruction,which is able to play a vital role in reconstruction of the extremities.