| ObjectivesTo observe the changes of patellar height after total knee arthroplasty and explore the correlation between patellar height correlation index and clinical function of knee joint after total knee arthroplasty.MethodsA retrospective analysis was performed on 86 patients who were hospitalized in the third department of orthopedics of Liaoning provincial people’s hospital from April 2016 to December 2017 with complete preoperative and postoperative clinical data and good follow-up.All the 86 enrolled patients were preoperatively diagnosed with osteoarthritis of the knee joint,and each patient had not received any other surgical treatment before surgery.Among the 86 patients enrolled in the study.18 were males and 68 were females.with an age distribution ranging from 53 to 89 years old and an average age of 68.4 years old.Patellar height correlation index(Insall-Salvati index,modified lnsall-Salvati index and Caton-Deschamps index)was measured on standard lateral X-ray images of the knee before and after surgery,and the differences between the three indexes were compared.According to the range defined by Caton-Deschamps index(0.6～1.2),patients were divided into patella baja group(12 knees),normal patella group(71 knees)and patella alta group(3 knees).Meanwhile,there were no statistically significant differences in preoperative indicators such as age,gender,height and body mass index,knee joint function and activity degree between the three groups.Preoperative and postoperative KSS clinical score,KSS functional score.Feller patella score,range of motion and other indexes of the three groups were recorded.SPSS 23.0 statistical software was used to analyze the clinical data.The measurement data were expressed as mean standard deviation(x±s)and t test was performed.Count data usage is expressed as row chi-square test.Spearman correlation analysis was conducted between the range of joint motion and patella height indexes.One-way anova was used for the comparison of knee function between groups with different patella heights.The comparison test level was set at both sides at 0.05.ResultsDuring the perioperative period,all the enrolled patients were safe and the operation was smooth.Postoperative complications occurred in 5 patients,including 2 patients whose healing was delayed due to fat liquefaction of the incision.In addition,3 cases of lower extremity deep vein thrombosis occurred,and the thrombus disappeared after symptomatic treatment such as anticoagulation and thrombolysis,and recovered well The follow-up of the enrolled patients was mainly made up of outpatient review and telephone follow-up.The follow-up interval was from 12 months to 32 months after the operation,with an average follow-up time of 18.3 months.All the enrolled patients received good follow-up.The preoperative and postoperative values of the Insall-Salvati index were(1.01±0.15)and(0.97±0.15)respectively,and the postoperative values of the Insall-Salvati index were not statistically significant(P>0.05).The preoperative and postoperative values of the improved Insall-Salvati index were(1.42±0.17)and(1.39±0.21),respectively.The difference between the preoperative and postoperative values of the improved Insall-Salvati index was not statistically significant(P>0.05);The Caton-Deschamps index before and after surgery was(0.83±0.09)and(0.73±0.15),respectively.The difference between the Caton-Deschamps index before and after surgery was statistically significant(P<0.05).After the operation,the patients were divided into groups according to the range defined by the Caton-Deschamps index(0.6～1.2),of which 0.6<Caton-Deschamps index<1.2 was the normal patella group(71 cases),Caton-Deschamps index<0.6 was the patella baja group(12 cases),and Caton-Deschamps index>was the patella alta group(3 cases).Postoperative KSS clinical score,KSS functional score.Feller patella score,knee range of motion and other indicators of the patella baja group were not as good as those of the normal patella group(P<0.05),and there was no significant difference between the patella alta group and the normal patella group.There was a moderate positive correlation between postoperative range of motion and postoperative Caton-Deschamps index.ConclusionsPatella height decreases to a certain extent after total knee arthroplasty.Acquired patella baja after total knee arthroplasty changes the biomechanical structure of the knee joint,which makes the functional score of the knee joint and the range of motion of the knee joint less than expected.Postoperative Caton-Deschamps index is closely related to knee function after total knee arthroplasty,and can be used as an important prognostic reference index.The key to prevent acquired patella baja lies in precise osteotomy and good joint line position during joint replacement. |
