Mid-and Long-term Follow-up Study Of Primary Total Knee Arthroplasty For Knee Osteoarthritis And Rheumatoid Arthritis

Objective To evaluate the mid-and long-term clinical efficacy and prosthetic survival rate of primary total knee arthroplasty for knee osteoarthritis and rheumatoid arthritis.Methods According to the exclusion and inclusion criteria,There were 453 patients(642knees)including 415 patients with osteoarthritis(584 knees)and 38 patients with rheumatoid arthritis(58 knees)underwent Scorpio posterior-stabilized total knee arthroplasty or NexGen LPS-FLEX total knee arthroplasty between May 2007 and May 2012,which were performed by the same chief surgeon at the General Hospital of Ningxia Medical University for knee osteoarthritis or knee rheumatoid arthritis.Patients were followed up from April 2019 to September 2019.The clinical evaluation was performed using the American Special Surgery Hospital(HSS)knee score,the American Knee Association(AKS)score,and the British Orthopaedic Association patient satisfaction score.Radiological evaluation use the Knee Society X-ray evaluation and scoring system to evaluate imaging data taken at the last follow-up.Paired t-test was used to analyze the data of preoperative and last follow-up.Revision of knee joint prosthesis for any reason as the end point,draw Kaplan-Meier survival curve,calculate prosthesis survival rate.Results Three hundred and twenty two patients(464 knees)(71.08%)including 288 patients with osteoarthritis(411 knees)and 34 patients with rheumatoid arthritis(53 knees)were followed up.Average follow-up duration was 9 years(range 7 to 12 years).Two hundred seventy nine patients(405 knees)received clinical evaluation,195 patients(291 knees)received radiological evaluation,32 patients(40 knees)died,1 patient(two knees)underwent open reduction and internal fixation of left knee periprosthetic fracture,10 knees were reviseddue to aseptic loosening of tibial tray(7 knees),periprosthetic infection(4 knees)and patello femoral pain(1 knee).At the last follow-up,the range of motion increased from preoperative average(84.49±19.23°)to(116.74±10.15°),the HSS score of knee joint increased from preoperative average(45.04±13.99)to(91.85±5.94),the AKS knee score increased from preoperative average(26.60±12.69)points to(92.75±8.97)points,the AKS function score increased from preoperative average(47.63±18.24)points to(73.85±14.74)points,the AKS pain score increased from preoperative average(0.69±4.16)points to(46.32±7.95)points,the differences were statistically significant(P <0.01).The patient's treatment satisfaction rate was 95.7%.The measured femoral angle was 82.45~103.45°,with an average of 94.05±2.59°;the tibia angle was 84.26~94.76°,with an average of 90.26±1.45°;the flexion angle of the femoral prosthesis was-6.91~14.72°,with an average of 4.15±2.70°;the tibia slope was 1.55~18.44°,with an average of 10.97±6.95°.When the knee joint prosthesis was revised for any reason as the end point of follow-up,the 9-year survival rate of the 464 knee prosthesis was 97.4%,the 9-year survival rate of the 397 knee Scorpio posterior-stabilized prosthesis was 97.8%;and the average 11-year survival rate of the 67 knee Zimmer NexGen LPS-FLEX prosthesis was 94.0%.Conclusion The mid-and long-term study indicates that primary TKA shows favorable clinical and radiological outcomes for knee osteoarthritis and knee rheumatoid arthritis and the survival rate is satisfactory.