Is traumatic meniscal lesion associated with acute fracture morphology changes of tibia plateau? A series of arthroscopic analysis of 67 patients

BACKGROUND Computed tomography(CT)has become a routine preoperative examination for tibial plateau fractures(TPFs).Assessing the location of the fragment and intercondylar eminence fracture can provide clinicians with valuable information;however,the evaluation of traumatic meniscal lesion(TML)and arthroscopic management are controversial.AIM To predict TML by three-dimensional skeletal anatomy changes in unilateral TPF and bilateral TPF on preoperative thin layer CT.METHODS Acute fracture of tibial plateau patients undergoing arthroscopic surgery between December 2017 and December 2019 were included in this retrospective study.The type,zone,and location of TMLs were diagnosed based on the operation records and/or arthroscopic videos.Measurement of three-dimensional fracture morphology included the following:Frontal fragment width of plateau,sagittal fragment subsiding distance(FSD),sagittal fracture line distance,sagittal posterior tibial slope,and transversal area ratio of fragment area)on preoperative CT three-dimensional plane.The correlation of TML with skeletal values was calculated according to unicondylar TPFs and bicondylar TPFs.RESULTS A total of 67 patients were enrolled in this study,among which 30 patients had TMLs,lateral/medial(23/7).FSD was a particularly positive factor to predict TML,with odds ratio of 2.31(1.26-5.63).On sagittal view of CT,FSD degree of 8 mm and posterior tibial slope exceeding 11.74°implied enhanced risk of TML in bicondylar TPFs.On coronal view,once fragment width of plateau surpassed 3 cm,incidence of TML reached 100%.On transverse view,area ratio of fragment as enhanced risk of 5.5%and FSD>4.3 mm for predicting TML were observed in unicondylar TPFs.CONCLUSION TML can be predicted by different parameters on preoperative CT views according to unicondylar fractures and bicondylar TPFs.

The generalized method for estimating reserves of shale gas and coalbed methane reservoirs based on material balance equation

As the main unconventional natural gas reservoirs,shale gas reservoirs and coalbed methane(CBM)reservoirs belong to adsorptive gas reservoirs,i.e.,gas reservoirs containing adsorbed gas.Shale gas and CBM reservoirs usually have the characteristics of rich adsorbed gas and obvious dynamic changes of porosity and permeability.A generalized material balance equation and the corresponding reserve evaluation method considering all the mechanisms for both shale gas reservoirs and CBM reservoirs are necessary.In this work,a generalized material balance equation(GMBE)considering the effects of critical desorption pressure,stress sensitivity,matrix shrinkage,water production,water influx,and solubility of natural gas in water is established.Then,by converting the GMBE to a linear relationship between two parameter groups related with known formation/fluid properties and dynamic performance data,the straight-line reserve evaluation method is proposed.By using the slope and the y-intercept of this straight line,the original adsorbed gas in place(OAGIP),original free gas in place(OFGIP),original dissolved gas in place(ODGIP),and the original gas in place(OGIP)can be quickly calculated.Third,two validation cases for shale gas reservoir and CBM reservoir are conducted using commercial reservoir simulator and the coalbed methane dynamic performance analysis software,respectively.Finally,two field studies in the Fuling shale gas field and the Baode CBM field are presented.Results show that the GMBE and the corresponding straight-line reserve evaluation method are rational,accurate,and effective for both shale gas reservoirs and CBM reservoirs.More detailed information about reserves of shale gas and CBM reservoirs can be clarified,and only the straight-line fitting approach is used to determine all kinds of reserves without iteration,proving that the proposed method has great advantages compared with other current methods.