Abstract: BACKGROUND: Periprosthetic fracture of the femoral of the knee after total knee arthroplasty is one of the common complications, and there is a lack of biomechanical research on the periprosthetic fractures of the femoral of the knee under different bone strength conditions. The three-dimensional finite element analysis can provide a biomechanical basis for clinical practice.
OBJECTIVE: To investigate the biomechanical changes of anterior femoral notching after total knee arthroplasty under different bone strengths, and to provide a mechanical basis for the clinical prevention of supracondylar femoral periprosthetic fractures after knee arthroplasty.
METHODS: The femoral CT data of healthy adults were obtained, and the three-dimensional model of femoral lateral replacement of the knee joint was established by Mimics, Geomagic studio, and Solidworks software. Anterior femoral notching models of different depths were constructed, and the models were imported into ANSYS software to analyze the changes of biological stress on the femoral condyle with different bone strengths and different anterior femoral notching depths. The stress changes of the femoral anterior condyle section after and before the filling of anterior femoral notching with bone cement were analyzed.

RESULTS AND CONCLUSION: (1) Under any bone strength, the supracondylar stress increased with the depth of anterior femoral notching. In normal bone conditions, there was a stress abrupt change point when the anterior femoral notching depth was between 3 mm and 4 mm. In the case of osteoporosis, there was a stress abrupt point when the anterior femoral notching depth was between 2 mm and 3 mm. (2) When anterior femoral notching occurred during knee arthroplasty and the depth exceeded the thickness of the bone cortex, the supracondylar stress of the femoral gradually increased as the bone strength decreased. (3) The stress of the anterior femoral condyle section decreased when the model with an anterior femoral notching depth of 3 mm was filled with bone cement. (4) The results show that anterior femoral notching should be avoided during knee arthroplasty, especially in patients with osteoporosis. If anterior femoral notching occurs during surgery, bone cement can be used to evenly fill the anterior femoral notching to reduce the supracondylar stress of the femur and reduce the incidence of periprosthetic fractures of the femoral joint 

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Key words: total knee arthroplasty, anterior femoral notching, osteoporosis, periprosthetic fracture of knee joint and femur, biomechanics, three-dimensional finite element analysis