Unicompartmental Knee Arthroplasty For Single Compartmental Knee Osteoarthritis

objective To report the medium-term results of UKA for osteoarthritis,and to discuss the indication and the key points of surgical technique.Methods A total of 55 unicompartmental knee arthroplasty patients(65 knees),8 males(10knees),39 females(46 knees)were performed from May 2005 to May 2008.The follow-up is well done except 7 lose follow-up and 1 death.The rate of fellow-up was 86.2%,mean periods was 27.7 months.The patients aged from 47-79 years old,the mean age was 63.9 years old,including 11 cases(14 knees) aged from 47-60 years old,36 cases(42 knees) aged from 60-79 years old.The mean weight was 67.4kg(40-90kg),including 40-80kg in 41 cases(49 knees),81-90kg in 6cases (7 knees).All patients are OA.There were 52 knees in medial compartment knee athroplasty,4 knees in lateral,9cases(18knees) in bilateral,73 oxford prothesis and 49 zimmer prothesis.The observation includes KSS knee score criterion of the preoperation and latest follow-up,the statistical analysis of ROM,the measurement of the angle of the posterior slope of the tibial implants and FTA,the radiology ofthe preoperation and postoperation.Results The mean clinical KSS knee score was from 40.3scores in preoperation to 95.4in postoperation,the mean function KSS knee score was from 44.6 to 94.1scores.The Statistical Analysis was significant (P＜0.05).The mean maximum flexion angle was from 102.2°in preoperation to 129.4°in postoperation.The Statistical Analysis was significant(P＜0.05) too.The mean FAT angle was 175.7°in medial UKA and 172.8°inlateral after operation.Prosthesis loosening,osteolysis surrounding prosthesis,secondary degeneration in other compartments were not observed after radiological follow-up.Conclutions 1 The UKA is a good way of therapy on knee compartment OA.2 The patients aged lower than 60 years old,weighted lower than 80kg, moderate pain in Patellofemoral joint,varus or valgus deformity larger than 5°,flexion contracture larger than 5°is not the contraindication of the UKA.3 For the anatomic prosthesis,release Patellar tendon to soft tissue below 2cm of media-posterior horn of tibial plateau is the way of correcting varus or valgus deformity.It is fobbiden to release soft tissue in oxford prothesis cases.In addition,the principle of over-correction does not apply to unicompartmental knee arthroplasty.