Infectious bone defect is bone defect with infection or as a result of treatment of bone infection. It requires surgical intervention, and the treatment processes are complex and long, which include bone infection control,bone defect repair and even complex soft tissue reconstructions in some cases. Failure to achieve the goals in any step may lead to the failure of the overall treatment. Therefore, infectious bone defect has been a worldwide challenge in the field of orthopedics. Conventionally, sequestrectomy, bone grafting, bone transport, and systemic/local antibiotic treatment are standard therapies. Radical debridement remains one of the cornerstones for the management of bone infection. However, the scale of debridement and the timing and method of bone defect reconstruction remain controversial. With the clinical application of induced membrane technique, effective infection control and rapid bone reconstruction have been achieved in the management of infectious bone defect. The induced membrane technique has attracted more interests and attention, but the lack of understanding the basic principles of infection control and technical details may hamper the clinical outcomes of induced membrane technique and complications can possibly occur. Therefore, the Chinese Orthopedic Association organized domestic orthopedic experts to formulate An evidence-based clinical guideline for the treatment of infectious bone defect with induced membrane technique ( version 2023) according to the evidence-based method and put forward recommendations on infectious bone defect from the aspects of precise diagnosis, preoperative evaluation, operation procedure, postoperative management and rehabilitation, so as to provide useful references for the treatment of infectious bone defect with induced membrane technique.

Objective:To investigate the short-term efficacy of anatomical calcaneal external fixator in the treatment of calcaneal fractures.Methods:A retrospective study was conducted of the 9 patients with calcaneal fracture who had been admitted to Department of Orthopedics, 920 Hospital of the PLA Joint Logistics Support Force between September 2019 and March 2020. There were 7 males and 2 females, aged from 23 to 66 years (mean, 41.3 years). The injury was caused by a fall from a height in 6 cases and a traffic accident in 3 cases. By the Sanders classification, there were 2 cases of type ⅡB, 2 cases of type ⅢAC, 3 type Ⅲ AB, one of type Ⅲ BC and one type Ⅳ. By the AO grading for closed soft tissue injury in the 8 closed fractures, there were 5 cases of grade Ⅰ and 3 cases of grade Ⅱ. The one open fracture was type ⅢB by the Gustilo-Anderson classification and treated with skin flap repair after debridement. All the 9 patients were treated with an anatomic calcaneal external fixator during stage-one or stage-two surgery (8 patients in stage-one and one in stage-two). The fracture union time for the patients was recorded; the ankle and hindfoot score of American Orthopedic Foot and Ankle Society (AOFAS) and the protocol of Association for the Study and Application of the Method of Ilizarov (ASAMI) were used at the last follow-up to assess the short-term efficacy.Results:Postoperative follow-up for the 9 patients ranged from 6 to 18 months (mean, 9.8 months). The duration of fracture union in the 9 patients ranged from 2 to 4 months (mean 2.8 months). The AOFAS ankle and hindfoot score at last follow-up ranged from 79 to 93 points (mean, 84.7 points) for the male patients (6 excellent and one good), and from 82 to 91 points (mean, 86.5 points) for the female patients (one excellent and one good). According to the ASAMI protocol at last follow-up, the short-term efficacy was rated as excellent in 6 cases, as good in 2 cases and as fair in one. The patients with closed fracture could get out of bed for rehabilitation on day 3 after surgery. None of the patients experienced such complications as pin tract infection and osteomyelitis during follow-up.Conclusion:The anatomic external calcaneal fixator demonstrates fine short-term efficacy in the treatment of calcaneal fractures, due to its advantages like anatomical configuration, a limited number of implants, and a possibility of partial weight-bearing for exercises on the third postoperative day.

Objective To explore the clinical application of our self-designed controllable and portable double-pin traction device on calf in the treatment of tibiofibular fractures.Methods Our controllable and portable double-pin traction device on calf was designed to fulfill the purpose of traction and address current problems in traction for tibiofibular fractures.This device is composed of double-hole connectors,nuts of various specifications,traction pin sleeves,2 transfixion pins and 2 threaded rods for traction.The transfixion pins are fixed at conventional traction positions.The threaded rods for traction are paralleled to the long axis of lower limb and located on both sides of the calf.Bone ends can be distracted by adjusting the nut of M8 width and the speed of pulling can be controlled.This device can be used not only for rapid traction during surgery but also for slow traction preoperatively.It was applied in the 30 patients with tibiofibular fracture who had been treated at Department of Orthopaedic Surgery,920th Hospital of Joint Logistic Support Force from January to December 2017.Their radiographs were taken before traction and at 3 and 6 days after traction to observe the changes in overlapped fracture ends and fracture gap.The lengths of distraction were measured.After limited open reduction,fracture gaps and tensions of surrounding soft-tissues were observed.Results Their radiographs before and after traction demonstrated that their overlapped and displaced fracture ends were distracted more or less.The length of distraction ranged from 7.2 mm to 45.8 mm (mean,23.1 mm);it was ＜ 15 mm in 6 cases,between 15 mm and 30 mm in 18,between 31 mm and 45 mm in 5,and ＞ 45 mm in one.Their radiographs showed that regular traction for 6 days was more obvious than that for 3 days.The limited open reduction revealed that the gap between fracture ends was expanded,the soft-tissue tension effectively relaxed,the overlapping of fracture ends diminished,and the dissection of surrounding soft-tissue and periosteum decreased,leading to less difficulty in reduction.In fractures near the joint or involving the articular surface,the joint space was expanded.The 30 patients were followed up for one to 16 months (mean,5.8 months).No such complications as pin site infection,traction fracture or osteomyelitis was observed.Conclusion Our self-designed controllable and portable double-pin traction device on calf is effective and advantageous,because it is simple,easy,light in weight,and controllable for traction speed.

The methods for evaluating left ventricular diastolic function completely and simply are lacking in our country at present. To solve this problem, we presents in this paper a novel method, which is developed according to certain algorithms and mathematic models and is carried out by a MATLAB program. This method mainly obtains dP/dt loops, and calculates four important indices, including left ventricular end-diastolic pressure (LVEDP), Maximal decrease in velocity of left ventricular pressure (--(dP/dt)max), Time constant of ventricular isovolumic relaxation (tau) and Chamber stiffness (Kd), according to the changes of left ventricular pressure. The results obtained from the experiment of isolated rat hearts during ischemia/reperfusion have demonstrated the usefulness and validity of this method. Therefore, with the use of tau and Kd as indicators, this is a sensitive and effective method for evaluating the left ventricular diastolic function, and it can be applied to early detection of left ventricular diastolic dysfunction.
Algorithms ; Animals ; Blood Pressure ; Diastole ; Humans ; In Vitro Techniques ; Male ; Models, Cardiovascular ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; physiopathology ; Ventricular Dysfunction, Left ; diagnosis ; physiopathology ; Ventricular Function, Left ; physiology

AIM: To analyze and compare the changes of pressure phase plane(PPP) derived τ and K on isolated rat heart during ischemia/reperfusion, and to explore the value of PPP derived τ and K for evaluation of left ventricular diastolic dysfunction. METHODS: LVEDP, -d(p/dt)_(max), τ and K were measured and calculated during ischemia/reperfusion in Sprague-Dawley rat hearts. Meanwhile, the level of lactate dehydrogenase (LDH) in the coronary effluent was measured, and the ultrastructure changes in myocardium were observed under electron microscope. RESULTS: Compared with control group, τ increased and K reduced significantly in each ischemic group in a time dependent manner (P<0.05). With prolonged ischemia, τ was even higher and K was even lower (P<0.05). Compared with control group, except ischemia 15 min, LDH in other groups increased significantly at 10 min and 20 min after reperfusion (P<0.05). Compared with ischemia 30 min, LDH of ischemia 45 min and ischemia 60 min were even higher at 10 min and 20 min after reperfusion (P<0.05). With prolonged ischemia, the abnormal changes of the myocardial ultrastructure were observed. CONCLUSION: PPP derived τ and K may be promising indexes for quantitative assessment of left ventricular diastolic function on isolated) rat heart during ischemia/reperfusion, and indication of the severity of ischemia/reperfusion injury.

AIM: To explore the protective effect of curcumin on high glucose-induced decrease in contraction of isolated rat aortic rings, and to elucidate its underlying mechanism. METHODS: The thoracic aortic rings with endothelium of male Sprague-Dawley rats were mounted on a bath system. Isometric contractions of aortic rings were measured. HO activity was also evaluated. RESULTS: (1)Four hours after incubated with 44 mmol/L of glucose (high glucose),the vascular contraction responses to phenylephrine (PE) decreased compared to control group (containing 11 mmol/L of glucose). (2)Coincubation with curcumin (3×10~(-11)-3×10~(-10) mol/L) and high glucose,the high glucose-induced decrease in contraction responses to PE of arteries was partly inhibited. (3)Four hours after incubation with curcumin,the HO activity in thoracic aorta increased. ZnPP,an inhibitor of HO-1,completely abrogated the protection effect of curcumin. (4)Methylene blue,an inhibitor of guanylate cyclase (GC),partly abolished the protective effect of curcumin. CONCLUSION: Curcumin prevents the high glucose-induced decrease in contraction responses to PE in intact aortic rings. The mechanism might be mainly involved in the activation of HO-1 and GC.

Objective To investigate the role of HO-1 in the protection of rat heart from anoxia/reoxygenation induced injury and its underlying mechanism.Methods LVEDP,LVDP and dp/dtmax were analyzed by the Langendorff method in isolated rat heart.Lactate dehydrogenase(LDH), infarct area,COHb and 6-keto-PGF1? were further determined in the experiment.Results After intraperitoneal injection of HO-1 inducer hemin,CO concentration in rat blood enhanced(P

OBJECTIVETo explore the possible mechanism of cyclovirobuxine D (CVB-D) in countering and inducing arrhythmia, by way of studying its electro-physiological effect on ventricular papillary muscles of rats in vitro.

METHODSThe transmembrane potential of rat's isolated right ventricular papillary muscles were recorded using conventional glass micro-electrode technique.

RESULTS(1) CVB-D in concentration of 13.3-63.3 micromol/L, showed prolonging effect on the action potential repolarization time, mainly the action potential duration 50 (APD50), APD70 and APD90, in dose-dependent manner, in concentration of 33.3-63.3 micromol/L, it could inhibit the resting potential, action potential amplitude (APA) and maximum depolarization velocity (Vmax) in dose-dependent manner. (2) CVB-D also showed time-dependent effect, the effect initiated 10 min after 20 micromol/L was perfused in ventricular muscle, the APD50, APD70 and APD90 were potentiated gradually along with prolongation of action time and reached the peak at 30-40 min, without any potentiation thereafter. (3) CVB-D could markedly prolong the effective refractory period (ERP) of action potential, increase the ratio of ERP/APD. (4) CVB-D in concentration of 33.3 micromol/L could induce frequent, multifocal spontaneous arrhythmia in some cells when the action time was longer than 45 min.

CONCLUSIONCVB-D has the action of anti-ventricular arrhythmia, the mechanism is correlated with the prolongation of APD and ERP of ventricular muscle as well as the increase of ERP/APD ratio, while it also has the effect of inducing arrhythmia, the mechanism might be concerned with excessive prolongation of APD and the inhibition on RP, APA and Vmax.

Action Potentials ; drug effects ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Arrhythmias, Cardiac ; chemically induced ; physiopathology ; Drugs, Chinese Herbal ; pharmacology ; Electrophysiologic Techniques, Cardiac ; Heart Ventricles ; drug effects ; In Vitro Techniques ; Male ; Myocytes, Cardiac ; cytology ; Papillary Muscles ; drug effects ; Rats ; Rats, Sprague-Dawley ; Refractory Period, Electrophysiological ; drug effects ; Ventricular Function

AIM: The effects of low-glucose on long-term potentiation (LTP) in the CA1 region of hippocapal slices of immature (15-16 days old) and adult (56-63 days old) rats were examined. METHODS: The technique of electrophysiology was used, and the slopes of the field excitatory postsynaptic potentials (S-EPSP) were measured. RESULTS: When slices were exposed to glucose medium at concentrations of 3 or 1.5 mmol/L, S-EPSP decreased significantly. In the slices from adult rats, only short-term potentiation was elicited by high frequency stimulation in the medium of 3 or 1.5 mmol/L glucose. However, in the slices from immature rats, LTP was still induced in the medium of 3 mmol/L glucose. CONCLUSION: Low-glucose medium depressed the synaptic transmission. In terms of the synaptic plasticity, the low-glucose endurance in immature rats was stronger than that in adult rats.

AIM: We examined the effect of interleukin- 2 (IL-2) on calcium handlin g of rat cardiomyocytes. METHODS: The effects of steady state an d transient chan ges in stimulus frequency on the intracellular calcium transient were investigat ed in the isolated ventricular myocytes with spectrofluorometry technique. RESULTS: Under the steady state (0.2 Hz), IL-2 at 2?10 5 U/L decr eased the peak [Ca 2+ ] i and amplitude of the [Ca 2+ ] i transient, increas ed the diastolic calcium level, and prolonged the decay of the calcium transient . At 1.25 mmol/L of extracellular [Ca 2+ ], when increasing the stimulus frequency from 0.2 to 1.0 Hz, diastolic calcium level and peak [Ca 2+ ] i as well as the amplitude of the transient were inc reased. The positive frequency relationship was blunted in the IL-2-treated myoc ytes and this was not normalized by increasing extracellular [Ca 2+ ] t o 2.5 mmol/L . The caffeine induced Ca 2+ release was increased with increase in stimu lus freq uency. IL-2 inhibited the frequency relationship of caffeine induced Ca 2+ releas e. The restitution was not different between control and IL-2 groups at the 1.25 mmol/L of extracellular [Ca 2+ ], which was slowed in IL-2-treated myo cytes when t he extracellular [Ca 2+ ] was increased to 2.5 mmol/L. CONCLUSIO NS: It is concluded that the blunted frequency response of IL-2-treated myocytes was resulted from the decrease in SR Ca 2+ release, which was related to depression of SR funct ion. Despite the evidence of depressed SR Ca 2+ uptake, the restitution o f ca lcium transient at 1.25 mmol/L of extracellular [Ca 2+ ] remains uncha nged, which maybe due to the increase in the Na +/Ca 2+ exchanger activi ty.