Effects Of Bone Wall Thickness Between HCD Decompression Channels And The Number Of Decompression Channels On The Biomechanics Of Proximal Femur

Objective: To compare the stress changes of femoral head after Honeycomb core decompression surgery(HCD)by biomechanical analysis of different bone wall thicknesses retained between 4,5 and 6 holes decompression channels.For the remedy of early and intermediate Osteonecrosis of the Femoral Head(ONFH)provides the basis for selecting the bone wall thickness and number of decompression channels between the appropriate HCD decompression channels.Methods: One patient with ONFH(ARCO stage Ⅰ)who was hospitalized for surgical treatment was selected for this study.The finite element analysis method was used to analyze the proximal femur data of the affected side of the patient by CT plain scan.Mimics21.0 was used to construct a three-dimensional model in stl format from Dicom format images.The stl file was imported into Geomagic Studio2014 for surface fitting and smoothing data processing.The model was imported into Hypermesh 2019 for grid division and optimization,and then the generated model was assembled by Abaqus 2020 software,the load was set,and the constraint conditions were defined for mechanical analysis.Finally,the finite element analysis of the 12 models was performed using Abaqus 2020 to observe the internal stress of the femoral head.The stress value of 30 nodes in the femoral head was recorded,and the data were analyzed and processed by SPSS 27.0 software.The measurement data were expressed as mean ± standard deviation,and the data were statistically analyzed by one-way analysis of variance.Results: 1.The internal stress changes of the femoral head with preserved bone wall thickness of 3,4,5 and 6mm between the holes after 4-hole HCD were compared: there was no significant difference between 4mm and 5mm(P>0.05),the thickness of the preserved bone wall increased from 3mm to 6mm,and the stress value decreased,and the stress of different bone walls was statistically significant(P<0.05).2.The internal stress changes of the femoral head with preserved bone wall thickness of 3,4,5 and 6mm between the holes after 5-hole HCD were compared: there was no significant difference between 5mm and 6mm(P>0.05),the thickness of the preserved bone wall increased from 3mm to 6mm,and the stress value decreased,and the stress of different bone walls was statistically significant(P<0.05).3.The internal stress changes of the femoral head with preserved bone wall thickness of 3,4,5 and6 mm between the holes after 4-hole HCD were compared:there was no significant difference between 4mm and 5mm(P>0.05).With the increase of the thickness of the preserved bone wall from 3mm to 5mm,the stress decreased,but increased sharply when the thickness of the preserved bone wall was 6mm.The stress of different bone walls was statistically significant(P <0.05).4.The same number of wells compared statistically significant(P< 0.05).The4-hole,5-hole,and 6-hole interosseous wall of the same interosseous wall were statistically significant(P<0.05).Conclusion: 1.Preservation of the intact interosseous wall in HCD is beneficial in reducing stress on the femoral head.With the increase of the thickness of the interosseous wall of the decompression channel,the stress value of the femoral head gradually decreases,indicating that the biomechanical properties of the femoral head can be better preserved by retaining a full thickness interosseous wall,and the mechanical strength of the femoral head can be significantly improved compared with the thin bone wall.2.In the same interosseous wall,the stress value of HCD in 4 holes and 5 holes decreased gradually,but the curve was gentle,and the stress value of 6 holes changed the largest.When the 6 holes retained the 6mm interosseous wall,the stress was the highest,which may be due to the channel penetrating the femoral neck cortex,destroying the biological performance and mechanical support of the proximal femur,and the surgical risk was high.It is concluded that the area of the femoral neck section is one of the factors worth considering during the operation.A small section cannot accommodate too many decompression channels,while a large section is the opposite.The optimal decompression effect of 5 holes is 6mm in the interosseous wall,and the stress on the femoral head is small,which not only retains the mechanical support but also improves the biological repair ability.3.The preservation of parallel interosseous wall between adjacent decompression channels in HCD has less damage to the proximal femoral anatomical structure than single channel or non-HCD surgery,and the effect of stress dispersion is better,which reduces the risk of postoperative fracture,and is better suitable for the treatment of ONFH patients.