Early And Mid-term Analysis Of Large Samples For Total Knee Arthroplasty With Medial Pivot Knee Prosthesis

Objective:To observe and analyze the early and mid-term clinical effect of medial pivot(MP)knee prosthesis through the preoperative and postoperative data obtained from the large follow-up samples after total knee arthroplasty with MP knee prosthesis.The effect of posterior cruciate ligament(PCL)retention or substitution on the use of MP knee prosthesis and the effect of body mass index(BMI)on the MP knee prosthesis were further analyzed.Methods:Part 1:Total knee arthroplasty cases using Advance~?medial pivot(AMP)prosthesis in Qingdao University Affiliated Hospital from January 2011 to September 2016 were selected for retrospective analysis.WOMAC,Knee Association Score(KSS)clinical score,KSS functional score,and range of motion(ROM)were collected before and at the last follow-up.The overall clinical effects of MP knee were evaluated by analyzing the scores,complications and survival rate.A total of 872 patients(1106 knees)were received an average of 48.16±15.62 months'follow-up.Part 2:Collection of scores is the same as Part 1.According to whether the PCL retention or PCL substitution,the groups were divided into 47 knees in cruciate retaining(CR)group and 1059 knees in cruciate substituting(CS).46 knees in CR group and 92knees in CS group were obtained by propensity score matching method(PSM).The effect of posterior cruciate ligament on the MP knee prosthesis was analyzed.Part 3:The scores were collected as part 1.According to the BMI level,the data were divided into non-obese group(BMI<28kg/m ~2)with 599 knees and obese group(BMI?28kg/m ~2)with 507 knees,and the clinical effect of BMI on the MP knee prosthesis was analyzed by stratification.Results:Part 1:There was a statistical difference in the scores between the preoperative and the last follow-up(P<0.05).The incidence of complications was 4.16%,and the Kaplan-Meier analysis of the AMP prosthesis survival rate was 98.93%.Part 2:Compared with data before TKA,the WOMAC score,KSS clinical score,KSS function score,and ROM were better in each matching group(p<0.05);there was no statistically significant difference in WOMAC,KSS clinical score,KSS function score,ROM and FJS(p>0.05).The incidence of complications(10.87%)in the CR-matched group was higher than that in the CS-matched group(3.26%)after matching,but there was no statistical difference(?~~2=2.01,P=0.16).The survival rate of the CR-matched group(100%)was higher than the CS-matched group(98.48%),but there was no statistical difference(?~~2=0.70,P=0.40).Part 3:At the last follow-up,the non-obesity group was better than the obese group in WOMAC score,KSS clinical score and KSS function score(P<0.05),but there was no statistical difference in ROM and FJS between the two groups(p>0.05).The incidence of complications(4.54%)was higher than that of the non-obese group(3.84%)without statistical difference(?~~2=0.33,p=0.56).The obesity group had a higher survival rate(99.05%)than the non-obese group(98.83%),but no statistical difference(?~~2=0.40,p=0.53).Conclusion:The"ball-in-socket"design of the MP knee prosthesis better mimics the characteristics of physiological knee motion mechanics.Excellent performance in early and mid-term scores,survival rates,and complications can be seen after implantation.Follow-up results showed no significant difference in PCL retention or PCL substitution group.There is a potential risk of PCL injury after surgery,the operator can choose the appropriate type of insert according to the characteristics of the patient and clinical experience.A high body mass index has a negative effect on the MP knee prosthesis,clinical effect for non-obese patients with the MP prosthesis better,but obesity is not a contraindication for MP prosthesis.