The Effect Of The Thickness Of Patellar Retention On The Biomechanics Of Patella And The Effect Of Knee Replacement

Objective: to establish a three-dimensional finite element model of knee joint with data,and analyze the effect of different thickness of patellar osteotomy on patellar strain and pressure of patellofemoral joint,as well as the effect of different thickness of patellar osteotomy on the effect of knee joint replacement in TKA.Methods: to reconstruct the data of knee joint and prosthesis based on the data of spiral CT,and to simulate different operation plans by Solid Works,then to establish the finite element model of knee joint in different osteotomy States,to realize the biomechanical analysis of different osteotomy plans.Patients with knee osteoarthritis who underwent total knee arthroplasty in the orthopaedic department of our hospital from July 2018 to March 2019 were included in the study.According to the thickness of patellar osteotomy in TKA,19mm(G1 group),18mm(G2group),17mm(G3 group),4(G4 group)mm were divided into four groups.25 cases were randomly selected,a total of 100 cases were selected.The average follow-up was December.The results were analyzed by SPSS 23.0 software package.The measurement data between the two groups were expressed by mean ± standard deviation(x ± s).T test was used.x~2 test was used to compare the count data,when p < 0.05,there was statistical significance.Results: in the analysis of the influence of different thickness of patellar osteotomy on the biomechanics of patella,in the three postures,the structural stress decreased gradually with the increase of the thickness of osteotomy,but when the thickness of osteotomy is more than 16 mm,the structural stress changes tend to be flat in the 0 ° postures and 45 ° postures.In the analysis of the effect of different thickness of patellar osteotomy on the curative effect of knee arthroplasty,the clinical score of knee joint after artificial knee arthroplasty was significantly higher than that before the operation,and the difference between groups was found that the thickness of patellar osteotomy was 16 mm Compared with group A,the clinical score of knee joint in 19 mm group improved more,but there was no difference among other groups;in patella score,the patella score after artificial knee replacement was significantly higher than that before operation.The results showed that the clinical score of knee joint in 19 mm,18mm and 17 mm groups improved more than that in 16 mm group,and there was no difference between the other groups.In terms of preoperative pain score,the preoperative pain score of artificial knee replacement was significantly higher than that before operation,and there was no significant difference between the two groups.Conclusion: with the increase of osteotomy thickness,the contact state between the knee bone and the prosthesis is is improved,the load distribution is more uniform,and the contact stress is gradually reduced;different osteotomy thickness of the patella less than 16 mm in total knee arthroplasty can improve the knee joint function score and patella score,but there is no significant difference in the preoperative knee pain score.