Study On The Direction And Depth Of Steinmann Pin For Acetabular Exposure In THA

Objective:The pelvic three-dimensional model was reconstructed using the Minics 17.0 software to study the osseous structure around the acetabulum,and the parameters of the acetabular pericardium were measured to provide a theoretical basis for clinically safe placement of the Steinmann pin.Methods:Pelvic CT data of a total of 38 hips of adults from December 2017 to December 2018 at the Second Hospital of Jilin University were collected.Three-dimensional reconstruction was performed using the data of 38 cases(76 hips)using Minics software.The acetabular cup mouth was regarded as a clock face,with the midpoint of the acetabular notch at the 6 o’clock position,and the left side as an example at 1,2 At the 4,10,and 11 o’clock positions,the three-dimensional image is cut.In the plane obtained by cutting,the distance from the acetabular rim is 1.0 cm at the above position,and within the angle range of 45°,the simulation is placed at intervals of 10°.A needle was used to measure the depth of the needle placement.The measured data were analyzed using SPSS 19.0 software,and the differences between the left and right sides and the different genders were compared.Results:The results obtained were as follows:(1)Right acetabular 11 o’clock position(1 o’clock on the left): optimal needle placement depth: male(38.1 ± 2.84)mm,female(31.62 ± 0.78)mm;optimal needle placement: in the tangential direction of the medial cortex of the acetabulum;adjustment angle: introversion 20° to extroversion 20°.(2)Right acetabular 10 o’clock position(2 o’clock on the left): optimal needle placement depth: male(32.64±1.43)mm,female(28.76±0.70)mm;optimal needle orientation: the tangential direction of the medial cortex of the acetabulum;adjustable angle: 20° introversion to 20° extroversion.(3)Right acetabular 1 o’clock position(11 o’clock on the left): optimal needle placement depth: male(38.1± 2.84)mm,female(33.76±3.34)mm;the best needle placement direction: the tangential direction of the inner cortex of the acetabulum;adjustable angle: inward tilt 20° to extrovert 20°.(4)Right acetabular 8 o’clock position(l4 o’clock on the left): optimal needle placement depth: male(30.24±1.94)mm,female(30.33±1.98)mm;optimal needle placement direction: tangential direction of the inner cortex of the acetabulum;adjustable angle: 20° inward to extrovert 20°.(5)Right acetabular 2 o’clock position(10 o’clock on the left): optimal needle placement depth: male(38.57 ± 3.42)mm,female(29.26 ± 2.42)mm;at the above angle Inner circle,the needle depth is statistically significantly different between the sexes,with men having a greater needle depth.There was no statistically significant difference between the left and right sides.Conclusion:1.In THA,the optimal safe Steinmann pin placement direction for the acetabular assist is the tangential direction of the medial cortex of the acetabulum,and the adjustable angle is 20° introversion and 20° extroversion.2.The Steinmann pin assisted in revealing the best safety needle placement depth in the acetabulum.Males have a greater depth than females.