A Preliminary Study Of Biomechanical And Functional Changes Of Lumbar Spine After TKA In Patients With KOA Combined With LSS

Objective:With the advent of China’s aging society,the incidence of diseases related to the elderly is also increasing.Among these diseases,knee osteoarthritis(KOA)and lumbar stenosis(LSS)are typical representatives,and there are many elderly people suffering from both diseases.Some of these patients need total knee arthroplasty(TKA)surgery first.In clinical practice,we found that some patients developed lumbar symptoms or aggravated original lumbar symptoms after TKA correction of knee flexion contracture deformity.A few patients developed lower limb muscle paralysis after TKA surgery and recovered muscle strength after lumbar decompression surgery.This project aims to investigate the changes of lumbar spine and pelvic sagittal balance in patients with KOA after TKA surgery by measuring lumbar lordosis(LL)and sacral slope(SS)before and after surgery,and to evaluate the influence of TKA surgery on lumbar symptoms in patients with KOA combined with LSS by comparing lumbar JOA scores before and after surgery.Methods:A total of 47 patients with KOA complicated with LSS who were admitted to the Department of Arthritis Surgery of the Second Affiliated Hospital of Inner Mongolia Medical University from May 2020 to August 2020 were selected.All met the diagnostic,inclusion and exclusion criteria.According to the preoperative data,the included cases were divided into three groups according to the knee flexion Angle(group A:knee flexion Angle≥30°,and 13 cases were eventually included;Group B:15°≤knee flexion Angle<30°,and 23 cases were included.Group C:knee flexion Angle>15°,and 11 cases were eventually included).After the same radiographs and surgical methods,LL and SS were measured 2 preoperatively and 6 months postoperatively,and JOA score table of lumbar spine was filled out by inquisitive patients and physical examination.Intra-group and inter-group comparison and correlation analysis were used to analyze the measurement parameters,and statistical significance was set as P<0.05.Results:1.There were significant differences in LL between the three groups before and after surgery(P<0.05).2.There were significant differences in preoperative and postoperative SS among the three groups(P<0.05).3.There was a positive correlation between LL and SS before operation in the three groups(r=0.648,r=0.719,r=0.855,<0.05).4.There was no significant difference in lumbar JOA scores between the three groups before and after surgery(P>0.05)5.There was no significant difference in preoperative lumbar JOA scores among the three groups(P>0.05)6.Comparison among the three groups showed a negative correlation between preoperative knee flexion Angle and preoperative LL and SS,which was statistically significant(r=-0.511,r=-0.670,P<0.05).Conclusion:In patients with KOA combined with LSS indicating that the greater the knee flexion Angle before surgery,the smaller LL and SS.There is a positive correlation between LL and SS,and both increase or decrease at the same time.There was no significant correlation between preoperative knee flexion Angle and lumbar symptoms.After TKA,with the correction of the knee flexion deformity,the lumbar forward flexion compensation disappeared,and LL and SS increased significantly.However,the volume of the lumbar spinal canal may decrease relatively with the disappearance of lumbar rotatory compensation.Therefore,patients with KOA combined with LSS may have lumbar symptoms that did not exist before TKA,and may also aggravate the original lumbar symptoms.