Hybrid External Fixation for Open Severe Comminuted Fractures of the Distal Femur

Background: The treatment of distal femoral open comminuted fractures is a major problem for orthopedic surgeon. The basic and important aim in treatment of these fractures is to assemble the condylar fragments and then fix the condyles to the femoral shaft by minimum handling of the bone and soft tissues. Objectives: To evaluate the treatment of distal femoral open comminuted fractures (type C2 and C3) with hybrid external fixator. Methods: Thirty-four patients with distal femur open comminuted fracture (type C2 and C3) were treated by hybrid external fixator between January 2005 and December 2008. All of the fractures were opened with extension to joint surface. 30 patients were male and 4 were female. Their average age was 30.5 years (17 to 72 years). Average follow up period was 36 months. 12 patients had isolated fracture and 22 patients had multiple fractures. The bony and functional results were evaluated by the association for the study and application of the method of Ilizarov (ASAMI) protocol and knee society score. Results: 29 out of 34 fractures (85%) had union without bone grafts. Average time of union was 6.1 months (4 - 19 ms). The average knee range of motion was 87.5 degrees (30 - 115 degrees). The bony results were excellent in 24 patients (70.5%), good in 6 (17.7%), fair in 2 (5.9%), and poor in 2 (5.9%), and the functional results were excellent in 10 (29.4%) patients, good in 14 (41.2%), fair in 6 (17.6%), and poor in 4 (11.8%), and the functional results were excellent in 10 (29.4%) patients, good in 14 (41.2%), fair in 6 (17.6%), and poor in 4 (11.8%) according to ASAMI protocol. According to the knee society score the functional results were excellent in 9 (26.44%) patients, good in 13 (38.26%), fair in 7 (20.6%), and poor in 5 (14.7%). Conclusion: Hybrid external fixator is an effective method for treatment of distal femoral open comminuted fractures (type C2 and C3) and may be considered as an alternative surgical methods in the management of these fractures.

Simultaneous, Asymmetrical, Comminuted and Bilateral Ballistic Fractures by Multiple Gunshot Wounds and a Review of Its Literature: A Case Report in Chad

Although open leg fractures are very common in orthopedics and traumatology, bilateral open leg fractures are extremely rare and are usually associated with an increased risk of complications. We report a case of a simultaneous, asymmetrical, comminuted and bilateral open fracture of the tibia and fibula by a firearm that occurred during an escape attempt in a 29-year-old prisoner. The pre-operative radiological assessment found an open fracture of both legs of the ballistic type;multiple traumatic gunshot wounds with a narrow entry hole and a wide exit hole. Early surgical intervention of intravenous antibiotics, tetanus prophylaxis and open fracture irrigation and debridement was performed within the 6 hour rule. The treatment consisted of a posterior splint followed by trimming andosteosynthesis using a FESSA external fixator from the military health service. A second operation was not needed. Evolution was favorable with ambulation starting from the 45th day. Simultaneous and bilateral tibia-fibula fractures by a firearm are exceptional, therefore, the treatment was surgical with the pre-operative and post-operative protocols well managed.

The finite element analysis of cemented long and short stem prosthetic replacement in aged patients with comminuted intertrochanteric fracture

Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution between cemented long

Biomechanical Comparison of Gourd-shaped LCP versus LCP for Fixation of Comminuted Tibial Shaft Fracture

The purpose of this study was to compare monotonic biomechanical properties of gourd-shaped LCP fixation with LCP fixation of human tibial shaft in gap fracture mode. Twenty paired fresh cadaveric human tibias were randomly divided into 4 groups （5 pairs each）： （1） axial loading sin- gle cycle to failure testing, （2） torsion single cycle to failure testing, （3） 4-point bending single cycle to failure testing, and （4） dynamic 4-point bending testing. A 7-hole 4.5 mm gourd-shaped LCP was se- cured on the anteromedial surface of 1 randomly selected bone from each pair, respectively, using 6 locking screws in the 1st, 2nd, 3rd, 5th, 6th and 7th hole with the middle hole unfilled and just located at the mid-diaphysis of the tibia. A 7-hole 4.5 mm LCP was secured on the other bone with the same method. Standard AO/ASIF techniques were used. After fixation finished, a 10 mm gap in the mid-diaphysis of tibia was created, centrally located at the unfilled hole. The axial, torsional, and bending stiffness and failure strengths were calculated from the collected data in static testings and statisti- cally compared using paired Student＇s t-test. The 4-point bending fatigue lives of the two constructs were calculated from the dynamic testing data and also statistically compared using paired Student＇s t-test. Failure modes were recorded and visually analyzed. P〈0.05 was considered significant. Results showed that the axial, torsional and bending stiffness of gourd-shaped LCP construct was greater （4%, 19%, 12%, respectively, P〈0.05） than that of the LCP construct, and the axial, torsional and bending failure strengths of gourd-shaped LCP construct were stronger （10%, 46%, 29%, respectively, P〈0.05） than those of the LCP construct. Both constructs failed as a result of plate plastic torsional deformation. After axial loading and 4-point bending testings, LCP failed in term of an obvious deformation of bent apex just at the unfilled plate hole, while the gourd-shaped LCP failed in term of a deformation of bent arc between the 3rd and 5th holes, which indicated a more consistent stress distribution on gourd-shaped LCP. Fatigue life of gourd-shaped LCP construct was significantly greater than LCP construct （153 836±2 228 vs. 132 471±6 460 cycles, P〈0.01）. All constructs failed as a result of fracture of the plate through the compression hole of the unfilled combination screw hole. The biomechanical testing showed that gourd-shaped LCP can provide greater stiffness and strength, and longer fatigue life than LCP. The gourd-shaped LCP may be more advantageous mechanically and may reduce the plate breakage rate clinically.

Postoperative Drains at the Donor Sites of Iliac-Crest Bone Grafts in Patients Who Had a Single Comminuted Long Bone Fracture

In this clinical trial, 90 patients admitted to orthopedics ward, Shahid Mohammadi Hospital, Bandar Abbass with a long bone fracture, comminuted more than 30%, were randomly divided into two groups. In the first group, after the completion of the operation, a single hemovaccum drain was inserted into the iliac crest wound, the site of cancellous bone removal, whereas the second group didn’t receive a drain. The two groups were followed for at least six months and the results were compared with Chi-Square and T-Tests. The two groups, at the end of the follow up period, had no statistically significant difference with regard to pain severity and need for dressing change (in the immediate postoperative period), hematoma formation and infection. So it seems that drain insertion in the wound of patients in whom cancellous bone is removed from the iliac crest, is not necessary.

The Early Outcomes with Titanium Radial Head Implants in the Treatment of Radial Head Comminuted Fractures

The study assessed the early functional outcomes with cemented titanium implants of radius in the treatment of comminuted fractures of radial heads. The functional outcomes of arthro- plasty with cemented titanium implants of radius in the treatment of radial head fractures （Mason Type Ⅲ： 6; Mason Type Ⅳ： 4） in l0 consecutive patients （mean age, 38 years） were evaluated over a mean time of 23.7 months （18-31 months）. The patients were assessed on the basis of physical examination, functional rating （Mayo） and radiographic findings. The parameters evaluated included motion, stability, pain, and grip strength. Five patients were considered to have excellent results, 4 patients had good results and l patient had fairly good results. There were no cases of infection, prosthetic failure, heterotopic ossification or dislocation. When medial collateral ligament was injured, radial head became the main stabilizing structure of the elbow. Titanium radial head implant may provide the stability similar to that of native radial head. We believe that titanium radial head im- plants may be indicated for the Mason Type Ⅲ and Mason Type IV radial head fractures.

Surgical Treatment of Calcaneal Comminuted Intrarticular Fractures: Long-Term Follow-Up

There is a controversy whether the comminuted calcaneal fractures should benefit more from conservative or from surgical treatment. Aiming to contribute to this unsolved clinical question we reviewed the long-term outcome (up to 96 months) of in 44 patients (mean age 35 years) with 47 calcaneal fractures who were treated surgically. In these patients open reduction and internal fixation were performed using a calcaneal reconstruction plate. The functional outcome was measured according to the Rowe Score and the level of pain by Visual Analog Scale. The objective outcome was estimated by the current radiographs. The clinical results were good to excellent in 69% of patients. Poor outcome observed in one patient who developed Complex Regional Pain Syndrome in his foot. The radiographic evaluation showed satisfactory reconstruction (according to the Boehler angle measurements) in 35 of operated calcanei. These results indicate on the satisfactory outcome of surgical treatment in the majority of the patients who were diagnosed with comminuted fracture of calcaneus.

Long-Term Clinical and Radiological Outcome in Primary Hemiarthroplasty for Comminuted Humeral Head Fractures in the Elderly: A 5 - 10 Years Follow-Up Prospective Study

Objective: In the constantly growing population of people beyond the age of 60 years, the incidence of complex comminuted humeral head fractures increases, thus increasing the need for prosthetic replacement. The purpose of this study was to determine the long-term results after primary hemiarthroplasty in patients older than 60 years. Methods: From 08/2010 to 12/2015 a prospective study of 54 patients (mean age 75 years) with complex humeral head fracture was performed at the University Hospital Rostock. 24 patients were available for follow-up after 5 - 10 years. Pain, the Karnofsky-index, and the range of motion were obtained as well as radiographs in two planes. The Constant-Murley score and the UCLA rating system were evaluated for functional assessment. Results: 15 patients were painfree. The Karnofsky index deteriorated from 94 preoperatively to 70. The Constant-Murley score of the operated extremity reached 47 points out of possible 100, the uninjured side scored 82 points. The age-specific Constant-Murley score showed more favorable results. The UCLA rating system values leveled up to 22 out of 35 points for the replaced shoulder and 33 points for the other arm. Radiologically, more than 50% of the implants were classified as non-centered and the acromio-humeral space diminished significantly. Conclusions: Primary hemiarthroplasty helps to restore a situation of little or no pain whereas functional and radiological outcome remains limited. Revision surgery or conversion to reverse shoulder arthroplasty was not indicated in any case supporting the clinical value of hemiarthroplasty.

Using shape-memory alloy staples to treat comminuted manubrium sterni fractures: A case report

BACKGROUND Comminuted manubrium sterni fractures are rare,and internal fixation methods are limited.This report explored a practical and feasible method of internal fixation for comminuted manubrium sterni fractures.CASE SUMMARY A 17-year-old female was injured in a car accident for which she underwent debridement and suturing of her head and anterior chest wounds in another hospital.Eight days later,the patient was transferred to our hospital for surgical treatment.The manubrium sterni was found intraoperatively to be split into three irregular fragments with obvious overlap and separation displacement.Meanwhile,a manubriosternal joint dislocation and left first rib cartilage fracture were observed.The retraction force of the shape-memory alloy staples was used to pull the fracture fragments together.Two more titanium locking plates were then used to fix the manubrium sterni and corpus sterni longitudinally,and the left first rib cartilage fracture was repositioned and fixed with a titanium locking plate.A postoperative computed tomography scan showed reduced and rigid fixation of the comminuted manubrium sterni fractures.The patient recovered well with no significant complaints of discomfort.The patient was discharged 10 days postoperatively after the stitches had been removed.CONCLUSION Shape-memory alloy staples had the advantage of being safe and effective during the repositioning and internal fixation of comminuted manubrium sterni fractures.Therefore,they provided a new surgical option for comminuted manubrium sterni fractures.

Pulp health and calcific healing of a complicated crown–root fracture with additional root fracture in a maxillary incisor: A case report

BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in theliterature.CASE SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical level.After the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival overgrowth.Cone-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival overgrowth.CONCLUSION This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.

Study on mechanism involved in posto perative reha-bilitation of comminuted fracture of patella

Objective To investigate mechanism involved i n knee joint rehabilition by compreh ensive rehabilitation therapy foll owing com-minuted fracture of patella surgery.Method25patients suffered from comminute d fracture of patella received rehabilitation training,drugs administration and physical therapy.Results Knee joint function was evaluated,e xcellent 22cases,good 2cases,favo rable 1case,good rate was 96%.Conclusion Rehabilitation of knee joint is satisfying in patients underwent compre hensive rehabilitation treatment.So,comprehensive rehabilitation treatment is valuable in clinic.

Teriparatide as a non-surgical salvage therapy for prolonged humerus fracture nonunion:A case report and literature review

BACKGROUND Fracture nonunion represents a challenging complication during fracture repair,often necessitating surgical intervention.Teriparatide,a recombinant human parathyroid hormone,has demonstrated promise in enhancing fracture healing,although its efficacy in treating established nonunion remains under investigation.CASE SUMMARY We report a case of a 27-year-old male who presented with a right humerus fracture following a traffic accident.Despite undergoing open reduction and internal fixation,the fracture resulted in a delayed union and subsequent nonunion.After 4 years of conservative management,teriparatide treatment was initiated due to persistent nonunion.Teriparatide injections were administered daily for 6 months,resulting in complete fracture healing and resolution of pain.CONCLUSION Our case demonstrates the successful use of teriparatide in treating a prolonged nonunion of a humerus fracture.Teriparatide may provide a valuable therapeutic option for established bone nonunion,even in cases that have not responded to conservative treatments.

Study on biomechanics of comminuted fracture of distal femur fixed by double plates

AIM:To develop a new internal fixation device for comminuted, unstable fractures of the distal femur,and to offer a guide for management of these injuries based on biomechanical studies.METHODS:Ten fresh adult femurs of cadavers.All femurs were similarly made of the models of supracondylar intercondylar fractures,then double plating with a plate in combination with a polythene plate,and the conventional sigle plating was served as the control.The biomechanic tests (compression,bending,torsion) were performed.RESULTS:The bending and torsion tests demonstrated that the double plating groups were much stronger (P< 0.01) than the single plating groups in anti bending and anti torsion.During the tests loading to failure, the double plating groups failed at a mean peak load of 11 540 N in axial compression,700 N in anterior bending 1 082 N in posterior bending,593 N in medial bending,1 010 N in lateral bending.CONCLUSION: Double plating with a plate in combination with a polythene plate is an excellent technique and design modification for severely comminuted fractures of the distal femur,which may provide a high stability and solidness so that early mobilization and weight bearing are allowed.

Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture caging.The simulations are innovative because of modeling discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changing the domain grid(i.e.no re-meshing).Further,multiple realizations of a preexisting fracture distribution can be analyzed using the same domain grid.The simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously:initially without permeating fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propagate the seeded fracture density hydraulically.FBCM combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing explicitly.Fractures are modeled as piecewise planar based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured rock.Simulations are presented for previously unfractured rock and for rock with preexisting fractures of horizontal,shallow-dipping,steeply dipping,or vertical orientation.Simulations of a single-well model are used to determine the pattern and spacing for a multiple-well design.The results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures,and in situ vertical compressive stress greater than horizontal.If preexisting fractures are steeply dipping or vertical,and considering the same in situ stress condition,well pressurization without fluid permeation appears to be the only practical way to induce new fractures and contain fracturing within the target domain.

Effect of extended nursing based on self-efficacy theory on the anxiety of patients with intertrochanteric fracture

BACKGROUND Extended care based on self-efficacy theory to elderly patients with intertrochanteric fractures will provide data reference to optimize the care plan of these patients,reduce patients’concurrent mental diseases,and improve prognosis.AIM To analyze the value of extended nursing based on the self-efficacy theory in older patients with intertrochanteric fractures.METHODS Older patients with intertrochanteric fractures(n=88)admitted to our hospital between January 2021 and December 2024 were randomly divided into two groups-the control group(n=44,routine nursing)and the observation group(n=44,extended nursing)-via balloting and treated for 12 weeks.The mental state,pain severity,limb function,and self-nursing ability of all patients before and after nursing were analyzed.RESULTS After nursing,the Hamilton Anxiety Scale and General Self-Efficacy Scale scores of patients in the two groups improved.Notably,Hamilton Anxiety Scale and General Self-Efficacy Scale scores in the observation group were lower and higher,respectively,than those in the control group(P<0.05).The pain severity in the observation group(2.64±0.22)was lower than that in the control group(2.85±0.41)(P<0.05).The recovery rate of limb function was higher in the observation group than in the control group(P<0.05).In addition,the self-nursing ability scores of the patients in both groups increased,with a significantly higher score in the observation group(P<0.05).CONCLUSION Extended nursing based on the self-efficacy theory can significantly improve mental state,relieve pain,and promote the recovery of limb function and self-nursing ability in older patients with intertrochanteric fractures.

Using fracture mechanics method to analyze the failure mechanism and equilibrium equation of interfacial loess-mudstone landslides

Loess-mudstone landslides are common in the Loess Plateau.Investigations into the mechanical theory of loess-mudstone landslides have become a challenging undertaking due to the distinctive interfacial properties of loess-mudstone and the unique water sensitivity characteristics of mudstone.Hence,it is imperative to develop innovative mechanical models and mathematical equations specifically tailored to loess-mudstone landslides.In this study,we analyze the fracture mechanism of the loess-mudstone sliding zone using plastic fracture mechanics and develop a unique fracture yield model.To calculate the energy release rate during the expansion of the loess-mudstone interface tip region,the shear fracture energy G is applied,which reflects both the yield failure criterion and the fracture failure criterion.To better understand the instability mechanism of loess-mudstone landslides,equilibrium equations based on G are established for tractive,compressive,and tensile loess-mudstone landslides.Based on the equilibrium equation,the critical length Lc of the sliding zone can be used for the safety evaluation of loess-mudstone landslides.In this way,this study proposes a new method for determining the failure mechanism and equilibrium equation of loessmudstone landslides,which resolves their starting mechanism,mechanical equilibrium equations,and safety evaluation indicators,thus justifying the scientific significance and practical value of this research.

Deformation mechanism and NPR anchor cable truss coupling support in tunnel through fault fracture zone

To address the issue of extensive deformation in the Tabaiyi Tunnel caused by the fault zone,nuclear magnetic resonance(NMR)technology was employed to analyze the physical and mechanical properties of waterabsorbing mudstone.This analysis aimed to understand the mechanism behind the significant deformations.Drawing from the principle of excavation stress compensation,a support scheme featuring NPR anchorcables and an asymmetric truss support system was devised.To validate the scheme,numerical analysis using a combination of the Discrete Element Method(DEM)-Finite Element Method(FEM)was conducted.Additionally,similar material model tests and engineering measurements were carried out.Field experiments were also performed to evaluate the NPR anchor-cable and truss support system,focusing on anchor cable forces,pressures between the truss and surrounding rock,pressures between the initial support and secondary lining,as well as the magnitude of settlement and convergence deformation in the surrounding rock.The results indicate that the waterinduced expansion of clay minerals,resulting from damage caused by fissure water,accelerated the softening of the mudstone's internal structure,leading to significant deformations in the Tabaiyi Tunnel under high tectonic stress.The original support design fell short as the length of the anchor rods was smaller than the expansion depth of the plastic zone.As a result,the initial support structure bore the entire load from the surrounding rock,and a non-coupled deformation contact was observed between the double-arch truss and the surrounding rock.The adoption of NPR asymmetric anchor-cable support effectively restrained the expansion and asymmetric distribution characteristics of the plastic zone.Considering the mechanical degradation caused by water absorption in mudstone,the rigid constraint provided by the truss proved crucial for controlling the stability of the surrounding rock.These research findings hold significant implications for managing large deformations in soft rock tunnels situated within fractured zones under high tectonic stress conditions.

Management and classification of the fracture of lateral process of talus:An overview and literature update

Fracture of the lateral process of the talus(FLPT)is uncommon in clinical practice and can be easily missed or misdiagnosed.In recent years,as researchers from all over the world have further deepened their research on FLPT,there has been a breakthrough in the classification,and the methods and principles of clinical management have changed accordingly;however,there is still no standardized guideline for the diagnosis and management of FLPT,and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 years.In this article,we review the clinical classification,classification-based therapeutic recommendations,and prognosis of FLPT,with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

A modified 3D mean strain energy density criterion for predicting shale mixed-mode Ⅰ/Ⅲ fracture toughness

The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is proposed.As the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.

Factors Influencing Proppant Transportation and Hydraulic Fracture Conductivity in Deep Coal Methane Reservoirs

The gas production of deep coalbed methane wells in Linxing-Shenfu block decreases rapidly,the water output is high,the supporting effect is poor,the effective supporting fracture size is limited,and the migration mechanism of proppant in deep coal reservoir is not clear at present.To investigate the migration behavior of proppants in complex fractures during the volume reconstruction of deep coal and rock reservoirs,an optimization test on the conductivity of low-density proppants and simulations of proppant migration in complex fractures of deep coal reservoirs were conducted.The study systematically analyzed the impact of various fracture geometries,proppant types and fracturingfluid viscosities on proppant distribution.Furthermore,the study compared the outcomes of dynamic proppant transport experiments with simulation results.The results show that the numerical simulation is consistent with the results of the proppant dynamic sand-carrying experiment.Under the conditions of low viscosity and large pumping-rate,a high ratio of 40/70 mesh proppant can facilitate the movement of the proppant to the depths of fractures at all levels.The technical goal is to create comprehensive fracture support within intricate trapezoidal fractures in deep coal and rock reservoirs without inducing sand plugging.The sand ratio is controlled at 15%–20%,with a proppant combination ratio of 40/70:30/50:20/40=6:3:1.Proppant pumping operations can effectively address the issue of poor support in complex fractures in deep coal formations.The research results have been successfully applied to the development of deep coalbed methane in the Linxing-Shenfu block,Ordos Basin.