Objective To study the short-term clinical outcomes of unicompartmental knee arthroplasty for medial compartmental knee osteoarthritis,and to compare 2 kinds of unicompartmental prosthesis.Methods From March 2010 to June 2013,data of 43 patients underwent unicompartmental knee arthroplasty (UKA) were retrospectively analyzed.17 patients (17knees) used rotating platform prosthesis,and 26 patients (28 knees) used fixed bearing prosthesis.There were 7 males (7 knees)and 9 females (10 knees) in rotating platform group,with an average age of 64.1 years (range,54-82 years);while 10 males (10knees) and 17 females (18 knees) in fixed bearing group,with an average age of 62.2 years (range,43-79 years).All patients presented signs of narrowed medial joint space,medial tenderness and pain on weight-bearing.X-ray and MRI were used for documenting joint narrowing and cartilage defect.The pain and the knee functions were recorded both pre and post-operatively with knee society score (KSS),2 cases of simultaneous anterior cruciate ligament (ACL) reconstruction were assessed with TegnerLysholm knee scoring scale as well.Results All 43 patients were followed up for 6 month to 37 months,and the average duration was 21.1 months.There were no dislocations,joint infection,deep venous thrombosis,prosthetic loosening,etc.The KSS in rotating platform group was 56.11 ±9.51 preoperatively,and 92.23±5.46 postoperatively.While the KSS in fixed bearing group was 57.11 ±9.56,and 93.69±6.37,respectively.There were statistical differences comparing between preoperative and postoperative KSS knee scores.There was no significant difference in KSS scores between rotating platform group and fixed bearing group.Conclusion Unicompartmental knee arthroplasty is a less invasive and effective method for knee osteoarthritis in medial compartment with less complications.There was no significant difference in clinical outcomes between rotating platform and fixed bearing design in terms of patients' satisfactory rate,clinical and functional outcomes in this short-term follow-up study.