Different Femoral Posterior Condyle Of Total Knee Arthroplasty On The Impact Of The Postoperative Maximum Flexion Degree By Preliminary Basic Research

Objective Total knee arthroplasty is an effective method to treat end-stage knee osteoarthritis, good postoperative knee flexion is considered an important factor in patients with surgical success and satisfaction.There were various factors that influencing the degree of knee flexion after knee replacement, among them the femur posterior condylar offset was put forwarded by Bellemans earliest in 2002, in recent years, the posterior condylar offset impact on the degree of knee flexion has reported more and more, their impact on the degree of knee flexion is controversial. In theory, the larger figures of posterior condylar offset, the later impingement between the posterior of tibial plateau and femur posterior bone cortex in the process of knee flexion, leading to larger flexion angle of the knee.This preliminary study applied basic experiment to discusses the relationship between posterior condylar offset and the maximum flexion degree of the knee after the total knee arthroplasty. Methods Experiment with 6 formalin fixed human lower limbs, length from hip to foot(including the foot), including 4 males and 2 females,there were no obvious scar and malformations of the knee, flexion activities freely;Experiment with Johnson De Puy PFC SIGMA PS prosthesis fixed platform system as the prosthesis,the distal femoral test model usually used typed 2,2.5,3, 4;Tibial side used the type of the prosthesis by measuring;the thickness of the meniscus implantation including 8 mm, 10 mm, 12.5 mm, 15 mm, 17.5 mm and 1 mm thickness of gasket;The experiment choose organic cement substitution for bone cement.The standardzation operation is to exposed the knee joint via medial parapatellar approach that incised thequadriceps tendon along its medial border,firstly, cut anterior femoral bone, the distal femoral equivalent bone cutting 9 mm, choosed the anterior reference femoral sizing guide, positioning the guide needle on the distal femoral anterior cortex level, tighten the indicating device size, mobile drill guide scale, were located in 2,2.5,3,4, located the guide nail at 2,2.5,3and4 seperately, with 3 ° external rotation,then drilled the nail in the location hole.Femoral side according tothe actual measurement size to finish anterior bone cutting and bone cutting between condyle. Tibial osteotomy special equipment to complete the platform, 8mm gap measure flexion gap is equal to the straighten gap; Installation of the actual femoral and tibial side test prosthesis, Choose 8 mm meniscus implantation, extremely pure lateral flexion 1: 1 X –rays image of the knee taken, measured and recorded the femoral condyles offset and the maximum flexion degree of the knee. Again, respectively, from small to large install the rest of the bone cutting models to the marked guide holes, finished anterior bone cutting and bone cutting between condyle. Then respectively according to the different measure data of femoral condyle prosthesis differences between a( see FIG. 1), select the appropriate tibial osteotomy plus data or use thicker meniscal implantation models, ensure constant flexion gap is 8mm, application of different types of knee joint femoral prostheses and extremely pure lateral flexion 1: 1 X –rays image were taken, measured and recorded the femoral condyles offset and the maximum flexion degree of the knee,.The results were applied to perform statistical analysis. Results 6 specimens of preoperative and intraoperative using different types of femoral prosthese measured value of femoral condyle offset and of preoperative and intraoperative using different types of femoral prosthese measured maximum flexion degree of the knee. The results were applied to perform statistical analysis by the Pearson correlation coefficient and Spearman correlation coefficient test. The same sample of different femoral condylar offset and knee maximum flexion degree after total knee arthroplasty has no relevance.(P>0.05,had no significant difference) Conclusion Through this experiment, we considerd that there was no correlation between the value of posterior condylar offset after total knee arthroplasty and the maximum flexion degree of the keen after total knee arthroplasty.