| Objective: to study the changes of Posterior Condylar Offset PCO before and after Total Knee Arthroplasty(TKA),the related factors,and the influence on Flexion of Knee before and after Total Knee Arthroplasty.Methods: A retrospective study was conducted from January 2018 to April 2019 in the Department of Joint Surgery of the First Affiliated Hospital of Dali University,total Knee Arthroplasty(TKA)was performed by the same surgical team in 50 patients,4 males and 46 females,with a posterior cruciate ligament replacement total knee prosthesis(Weigao Yahua GKPS total knee prosthesis),standard lateral radiographs of knee joint were taken before and after TKA,and the femoral offset before and after Tka were measured and recorded,the maximum flexion angle of the knee was measured and recorded before,postoperative 1 day,1month,3 months and 6 months respectively.Statistical data were calculated using R(3.6.3).Results: according to the condition of PCO before and after operation,the patients were divided into three groups: the group with decreased PCO,the group with increased PCO<3mm,and the group with increased PCO>3mm.All 50 patients were followed up.The follow-up time was 1 month,3 months and 6 months postoperatively.During the follow-up period,none of the patients had periprosthetic fracture,periprosthetic infection or aseptic loosening.1.PCO before and after operation: One-way ANOVA Test was used.The PCO before operation:the group with decreased PCO was 35.56 ± 3.67,the group with increased PCO< 3mm was 32.27 ± 3.37,and the group with increased PCO>3mm was 29.33 ±4.51.The PCO after operation:the group with decreased PCO was31.35±3.38 mm,the group with increased PCO < 3mm was 34.11±3.18 mm,and the group with increased PCO>3mm was35.76±5.7mm。There were significant differences between the two groups(PCO p = 0.00015 before operation and PCO p = 0.0197 after operation).2.Preoperative,postoperative 1 day,postoperative 1 month,postoperative 3 months,pos toperative 6 months maximum knee flexion angle: preoperative,postoperative 1 day,po stoperative 1 month,preoperative 6 months maximum knee flexion angle of patients u sing One-way ANOVA Test.The maximal flexion angle of knee joint before operatio n:the group with decreased PCO was 103.33 ± 14.35°、the group with increased PC O < 3mm was 120 ± 14.24°、the group with increased PCO>3mm was 102 ± 11.85°。There was no significant difference in statistical data(P = 0.0807);The maximal fle xion angle of knee joint was 1day after operation:the group with decreased PCO wa s 97±10.14°、the group with increased PCO < 3mm was 100±4.5°、the group with inc reased PCO>3mm was 95±11.53°。There was no significant difference in statistical dat a(P =0.296);The maximum flexion angle of knee joint was 1 month after operation:the group with decreased PCO was 110±6.17°、the group with increased PCO < 3mm was 120±8.86°、the group with increased PCO>3mm was 120±6.09°。There was no s ignificant difference in statistical data(P =0.296);The maximum flexion angle of knee joint was 3 month after operation:the group with decreased PCO was 120±4.14、th e group with increased PCO < 3mm was 120±4.59°、the group with increased PCO>3mm was 120±3.8°。There was no significant difference in statistical data(P =0.184);The maximum flexion angle of knee joint was 6 month after operation:the group wit h decreased PCO was 120±4.58、the group with increased PCO < 3mm was 120±4.49°、the group with increased PCO > 3mm was 120±4.1°。There was no significant di fference in statistical data(P =0.576).3.Subgroup analysis:(1)the group with decreased PCO,Welch Two Sample t-test was used to compare the maximum flexion angle of knee joint before and postoperati ve 1 day,There was no significant difference in statistical data(t = 1.3958,p = 0.1749)。Wilcoxon Rank Sum Test was used to compare the maximum flexion angle of k nee joint before operation and 1 、3、6 month after operation.The differences were st atistically significant.(1 month:W = 64.5,P =0.03907、3 month:W =40.5,P =0.00121、6 month:W = 29.5,P =0.0001971).(2)The group with increased PCO < 3mm:Wilcoxon Rank Sum Test was used to compare the maximum flexion angle of k nee joint before operation and postoperative 1 day,the differences were statistically si gnificant(W =176.5,P =0.006709).Wilcoxon Rank Sum Test was used to compare th e maximum flexion angle of knee joint before operation and 1 、3 month after operat ion,There was no significant difference in statistical data(1 month:W = 89,P =0.3062;3 month:W = 74,P = 0.07448).Wilcoxon Rank Sum Test was used to compare the maximum flexion angle of knee joint before operation and 6 month after operatio n,the differences were statistically significant(W = 74,P = 0.04791).(3)The group with increased PCO > 3mm:Wilcoxon Rank Sum Test was used to compare the max imum flexion angle of knee joint before operation and postoperative 1 day、1 month,the differences were statistically significant(postoperative 1 day:W =280.5,P = 0.02735;1 month:W = 70.5,P =0.000287);Wilcoxon Rank Sum Test was used to comp are the maximum flexion angle of knee joint before operation and 3、6 month after o peration,There was no significant difference in statistical data(3 month:W = 41,P= 5.272e-06;6 month:W = 30,P = 1.132e-06).Conclusion: The maximum flexion angle of the knee joint was not related to the increase or decrease of the posterior femoral condylar offset.But if PCO increases too much,it will increase the pressure of patellofemoral joint and limit the flexion and extension of knee joint.If PCO decreases too much,the posterior border of tibial plateau prosthesis and the posterior cortex of distal femur will collide,which will limit the flexion of knee joint.The degree of PCO is related to the recovery of knee joint flexion and extension function after surgery,which should be paid more attention to,and the PCO should be reconstructed as far as possible before surgery,to achieve the best knee joint condition to restore knee joint function. |
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