Correlation Between The Changes Of Joint Line Measured By X-ray And The Function Of Knee Joint After Unicompartmental Knee Arthroplasty

Background:With the aggravation of population aging,the incidence of knee osteoarthritis(KOA)is increasing gradually,KOA is more common in the medial compartment of the knee in most patients.Lateral compartment osteoarthritis accounts for only 1/8 of unilocular osteoarthritis.For patients with anteromedial knee KOA,with the prosthesis design more in line with human biomechanics and clinical surgery technology improved,total knee arthroplasty(TKA)has been gradually replaced by unicompartmental knee arthroplasty(UKA).Previous studies on the anatomical location of joint line(JL)during TKA and TKA revision showed that,the change of joint line is an important guarantee for the postoperative joint function and the service life of the prosthesis.However,there are few reports on the dynamic changes of knee joint line in patients with anteromedial knee KOA after UKA at home and abroad.In addition,there have been no reports on the correlation between the dynamic changes of knee line and joint function in patients with UKA after different anatomical markers.The purpose of this study was to investigate the relationship between the changes of articular line and knee function after unicompartmental knee arthroplasty,it provides a reliable basis for clinicians’ preoperative planning,intraoperative osteotomy and postoperative evaluation.Objective:The correlation between the changes of medial compartment joint line,lateral compartment and global knee joint line and knee joint function after unicompartmental knee arthroplasty,to clarify the reliability of different anatomical markers for evaluating the comprehensive evaluation of joint function after UKA in patients with KOA.Method:In this study,there were 27 effective research subjects,27 knee joints(10 left knee joints,17 right knee joints),including 12 males(5 left knee joints,7 right knee joints)and 15 females(5 left knee joints,10 right knee joints).The average age was(64.8±7.6)years,with age ranging from 41 to81 years.The distance parameters and Angle parameters of the knee joint were measured on the standard anteroposterior and lateral X-ray films of the knee joint and the panoramic films of the bearing position of both lower limbs,and the statistical results were analyzed.Results:The distance between adductor tubercle of femur and knee joint before and after operation(46.46±3.79 mm,49.00±3.08 mm,t=-4.610,P<0.001),height of joint line of medial compartment of knee joint(4.87±4.63 mm,6.72±3.06 mm,t=-2.679,P=0.013).The proximal medial Angle of the tibia before and after surgery(84.62±2.97°,86.98±2.45°,t=-4.923,P<0.001),the distal lateral Angle of the femur(89.20±2.71°,85.90±3.04°,t=5.506,P <0.001),inverted Angle of lower limb line(9.30±5.30°,4.50±2.41°,t=6.372,P < 0.001).According to K-L classification,there were significant differences in the height of joint line of medial compartment of knee joint before surgery(7.56±3.18 mm,6.13±3.22 mm,1.55±5.45 mm,F=4.655,P=0.02),there was no significant change in the joint line height of the lateral compartment of the knee joint(13.38±2.79 mm,13.75±3.42 mm,11.13±2.75 mm,F=1.976,P=0.161).Conclusion:After UKA in AMOA patients,the distance from the nodules of the adductor femur to the knee joint line and the height of the joint line of the medial compartment of the knee joint.Compared with preoperation,the distal lateral Angle of the femur,the proximal medial Angle of the tibia and the strength line of the lower limbs were significantly improved,and recovered to the normal physiological level;the changes of the joint line height of the medial compartment of the knee joint and the overall joint line height of the knee joint were both significantly increased and linearly correlated.It can be used as a reliable parameter to evaluate the comprehensive evaluation of knee joint after UKA.In the K-L grading group,the height of the joint line of the medial compartment of the knee joint was significantly reduced;the overall knee line and the joint line height of the medial compartment of the knee were increased after surgery,and the closer the recovery was to the normal physiological level,the better the HSS score of the knee function of the patients.The height of the knee line in the lateral compartment of the knee joint did not change significantly.