Mid-Term Results Of Oxford Unicompartmental Knee Arthroplasty

Part Ⅰ: Factors Affecting Outcomes of Oxford Unicompartmental Knee Arthroplasty and Patient SatisfactionPurpose: Investigating the clinical outcomes and patient satisfaction of Oxford unicompartmental knee arthroplasty(UKA),and analyzing the factors affecting the clinical outcomes and patient satisfaction of Oxford UKA.Methods: A total of 97 patients(104 knees),who underwent Oxford UKA in our institution from November 2013 to December 2018,were registered.The patient’sdemographic information,preoperative scores,preoperative imaging information and surgical information were searched from the electronic medical record system.Routine follow-up was performed on the 3rd day,1st month,3rd month,6th month,12 th month after operation and every year thereafter.Clinical scores(NRS,KSS)and patient satisfaction were recorded in each time.X-rays were taken to measure the position of prostheses and determine whether the implants was loose or dislocated.All patients were followed up for at least 1 year.Results: Eighty-seven patients(87 knees)were followed up in the end.Both clinical scores(NRS,KSS)and knee varus deformities were significantly improved and corrected after operation(p<0.05).Postoperative complications occurred in 6 patients(7.5%),and no loosening or dislocation of prosthesis was found.Later surgery(defined as shorter time since surgery)and smaller Angle E(tibial component obliquity deviation)were predictive factors for the more improvement of KSS score,respectively(p=0.009;p=0.024).At the last follow-up of 87 cases,there were 73cases(83.9%)in the high patient satisfaction group and 14 cases(16.1%)in the low patient satisfaction group.Higher postoperative KSS and smaller Angle E were predictors of higher patient satisfaction(p=0.001;p=0.032).The area under the ROC curve of the postoperative KSS was 0.938,indicating that the postoperative KSS was a good predictor of patient satisfaction,and the prediction effect would become better when combined with Angle E(area under ROC curve =0.953).Conclusion: Oxford UKA can significantly improve clinical scores(NRS,KSS)and correct knee varus deformities.Later surgery and smaller Angle E are predictors for the more improvement of KSS.Learning curve effect Oxford UKA results,surgeons can accumulate surgical experience by increasing the amount of surgery,which can lead to more improvement of KSS.Both postoperative KSS and Angle E are good predictors of patient satisfaction,and the predictive effect is better when used in combination.Part Ⅱ: Comparison of the Mid-term Results of Unicompartmental Knee Arthroplasty in Treatment of Medial Osteoarthritis and Spontaneous Osteonecrosis of the KneePurpose: Comparing the mid-term clinical outcomes and patient satisfaction of unicompartmental knee arthroplasty(UKA)in medial osteoarthritis(MOA)of knee and spontaneous osteonecrosis of the knee(SONK).Methods: Searched through the electronic medical record system for patients,who underwent Oxford unicompartmental knee arthroplasty in our institution from November 2013 to December 2018.Recorded the patient’s demographic information,preoperative scores,preoperative imaging information and surgical information.The diagnosis of SONK was confirmed according to preoperative knee radiographs and MRI.Routine follow-up was performed on the 3rd day,1st month,3rd month,6th month,12 th month after operation and every year thereafter.Clinical scores(NRS,KSS)and patient satisfaction were recorded in each time,and X-rays were taken to determine whether the implants were loose or dislocated.All patients were followed up for at least 1 year.Results: A total of 80 patients(87 knees)were followed up,including 65 patients(72knees)in the MOA group and 15 patients(15 knees)in the SONK group.There were no statistical differences in postoperative clinical scores(NRS,KSS,improvement of KSS),femorotibial angle(FTA),knee varus correction,proportion of patients with high satisfaction or complications between the MOA group and the SONK group.However,the SONK group was significantly better than the MOA group in the improvement of postoperative NRS(7.0 vs.5.0;P = 0.004).Conclusion: Patients in the MOA group and the SONK group underwent unicompartmental knee arthroplasty with similar mid-term followed-up outcomes,and UKA is a reliable treatment for patients in the mid and late stage of SONK.