Effect Of Selection Of The Posterior Tibial Slope On The Knee Function After The Unicompartmental Knee Arthroplasty

ObjectiveAt present,there is still no international consensus on the selection of posterior tibial slope(PTS)in mobile-bearing prosthesis unicompartmental knee arthroplasty(UKA).In this study,we intended to compare the difference of different PTS in the reconstruction of knee function and the relief of knee pain after the mobile-bearing prosthesis UKA,in order to provide better clinical effect in accurate osteotomy.MethodsThe data of patients who underwent UKA in the Department of Arthiology of Guangdong Provincial Hospital of Traditional Chinese Medicine between January 2015 and December 2019 were retrospectively analyzed.There were 60 patients who met the inclusion and exclusion criteria.According to the absolute value of the difference in the PTS,there were 32 knees in Ⅰ group(0≤D≤2°),while 9 patients were male and 23 female,with a average age of 63.31 years(range,53～72 years),and there were 28 knees in Ⅱ group(D>2°),11 males and 17 female.And the average age was 62.25 years(range,53～72 years).All the cases were completed by the same chief surgeon.The patients’ gender,age,weight,height and body mass index(BMI)were recorded,at the same time,the anteroposterior bilateral lower extremity negative-position X-ray and three-dimensional CT reconstruction were performed before and after operation,in order to measure the medial PTS and range of motion(ROM).Evaluate the Western Ontario and McMaster universities osteoarthritis index(referred WOMAC index)and the American knee society knee score(referred KSS score)at preoperative and last follow-up.We use SPSS 18.0 software for data processing and statistical analysis(P<0.05 was considered statistically significant).ResultsThe characteristics of patients(gender,age,weight,height and BMI)were not statistically significantly different between the two groups.All patients didn’t have any infection,aseptic prosthesis loosening,polyethylene gasket dislocation,unexplained pain and other complications.The mean of KSS score,WOMAC index and ROM were statistically significant between preoperative and postoperative(P<0.05).Differences in postoperative KSS score and WOMAC index between the Ⅰ and Ⅱ groups were statistically significant(P<0.05),but there was no significant difference in ROM(P=0.20).ConclusionUnder grasping the UKA indication accurately,the UKA can authentically relieve the pain and improve the knee function.In terms of selection of PTS in UKA,the patients whose absolute value of PTS difference was less than 2°before and after surgery showed significant improvement in knee function and pain relief compared with patients whose absolute value of PTS difference was less than 2°,but there was no significant difference in the improvement of knee ROM.In conclusion,we suggest that the PTS should be recovered to within 2°of the physiological PTS in UKA.At the same time,computer-assisted unicompartmental knee arthroplasty can provide more accurate osteotomy.