Study On The Changes Of Joint Line After TKA In Patients With Varus KOA

Objective The purpose of this study was to investigate the relationship between varus deformity and joint line changes after total knee arthroplasty in patients with end-stage osteoarthritis.Methods A total of 83 patients(118 knees)who underwent total knee arthroplasty in our department from August 2018 to January 2020,which also met the inclusion criteria were retrospectively analyzed.All the included cases were due to routine total knee arthroplasty with varus deformity.All knees were implanted with the same posterior-stabilizing prosthesis.The cases with flexion deformity greater than 10°before operation or previous history of surgery around the knee and fracture around the knee were excluded.The patients were divided into mild varus group(< 10 °),moderate varus group(10 °-20 °)and severe varus group(> 20 degrees)according to the degree of varus deformity before the operation.The distance from adductor tubercle to the distal femur was measured by measuring software on the anteroposterior film of the knee before and after operation,and the actual distance was calculated according to the actual size of prosthesis.SPSS18.0 was used to analyze whether there were differences in the changes of joint line before and after operation,whether the distance between adductor tubercle and joint line changed before and after operation,and whether the proportion of joint line changes greater than 4 mm among groups was consistent.Results There were 60 cases in mild varus group,44 cases in moderate varus group and 14 cases in severe varus group.There were no significant differences in gender,age and body mass index among the three groups(P > 0.05).The length of adductor tubercle to distal femur was(40.61 ±3.94)mm and(40.32 ± 3.61)mm in 118 cases before and after operation,respectively,and there was no significant difference between them before and after operation(P > 0.05)In mild varus group,the postoperative length between adductor tubercle and distal femur minus the preoperative length was(-0.12 ± 2.13)mm,in moderate varus group was(0.13 ± 2.54)mm,and in severe varus group was(-0.4 ± 1.91)mm.There was no significant difference in joint line changes among the three groups(P > 0.05).In 60 cases of mild varus group,there were 2 cases with joint line change greater than 4 mm,5cases in 44 cases of moderate varus group,and 1 case in 14 cases of severe varus group.There was no significant difference in the proportion of joint line change greater than 4 mm among the three groups(P > 0.05).Conclusion1.Preoperative varus deformity had no significant effect on postoperative joint line changes,and different degrees of varus deformity had no difference in joint line changes.2.Measured resection,posterior-stabilizing prosthesis and soft tissue release technique have good effect on maintaining the stability of joint line in varus cases...