Study On TT-TG Measurement Method And The Correlation Of Other Patellar Stability Parameters

Objective: In this study,CT image fusion technique was used to analyze the CT images of the knee joint,to measure the TT-TG distances of different reference planes of the femoral trochlear notch,and to analyze the influence of the different position of the femoral trochlear on the TT-TG measurement.And the TT-TG and TT-PD distances were obtained at every references with the two methods which is the deepest point of the femoral trochlear groove and the deepest point of the femoral condyle space as the vertical line of the femur.To observe the change of the groove angle,the ratio between patellar ligament length and patellar length(PLL / PL),the difference of medial and lateral patellar retinaculum length,and to explore the correlation between these parameters and TT-TG distance.Subjects and methods: This study is divided into two parts,the first part of the TT-TG measurement method,recruited knee joint CT examination 60 patients which all dose in our hospital,including 42 males and 18 females,the left knee 31 cases,29 cases of right knee,aged 18 to 40 years old,the CT scan obtained by the thin image data into the workstation for post-processing reorganization and measurement.The TT-TG values were measured and analyzed by variance,and the TT-PD values were measured on the five references and analyzed by variance.The correlation between the TT-TG values and the TT-PD values which measured by the five reference planes was analyzed.The difference of TT-TG between left and right knee and the difference of TT-TG in male and female knee were compared.The second part is the correlation between TT-TG and other patellar stability parameters.On the above mentioned cases,the angle of the trench angle is measured on the superimposed image obtained on the five aliquots,the length of the patella and the length of the patellar ligament are measured Insall-Salvati ratio method to calculate the ratio,measuring the patellar,lateral support band length.The distance between the patellar angle,patellar ligament length and patellar length,the length of the medial and lateral patellar retinaculum and do the correlation analysis with the measured TT-TG distance which were calculated from the five reference levels.Results: There was no significant difference in TT-TG value between the differentpositions of femoral trochlear(P> 0.05),and there was no significant difference between the TT-PD values(P >0.05),however,the difference between TT-TG and TT-PD was statistically significant(P <0.05).TT-PD values was larger,and there was a significant positive correlation between TT-TG and TT-PD values.There was no significant difference in TT-TG between left and right knee joint(P> 0.05).There was no significant difference in TT-TG between male and female(P> 0.05).The difference of femoral trochlear groove angle was statistically significant(P <0.05)under different location of the femoral trochlear as reference level.There was no correlation between the length of patellar ligament,patellar length,the length of medial and lateral patellar retinaculum and TT-TG.Conclusion: TT-TG values can be used as the evaluation parameters at any point under the femur pulley ditch.The TT-TG and TT-PD values of the two different methods are different,in the latter part which select the deepest of the femoral condyle space as femoral end vertical line measurement method is larger.In the left and right TT-TG value comparison,found that the left TT-TG value is lower than the right side,may be related to the advantages of left and right limbs.The TT-TG value of male and female knee joint had no effect on the TT-TG value of the knee joint,and the TT-TG of male knee was larger than that of female.TT-TG value can reflect the stability of the patella,there was no significant correlation between the tachycardia,patellar ligament length,patellar length ratio,medial and lateral patellar retinaculum length and TT-TG value,but the trench groove,patellar ligament length and patellar length ratio,these parameters are important factors for patellar stability.Medial and lateral patellar retinaculum as a fixed patella factors,these parameters are independent of patellar stability,so the evaluation of the stability of the patella requires multi-parameter measurements.