Mobile bearing UKA compared to fixed bearing TKA: a randomized prospective study

We prospectively evaluated a consecutive series of 56 patients with unicompartmental knee arthritis who underwent unicompartmental knee replacement or total knee arthroplasty and received an average of 52months of follow-up. These patients were enrolled in a prospective randomized clinical trial. There were no significant differences in the pre-operative parameters of both groups. All the patients were followed up and evaluated preoperatively and yearly, the data was collected and statistical analysis was performed. At an average of 52months after surgery the mean Knee Society score was 80.5 (range: 70-100) and 78.9 (range: 70-87) for Unicompartmental knee replacement and total knee arthroplasty, mean range of postoperative motion for TKA is 115(0)±4(0) and 117(0)±7(0) for the group of UKA, with the numbers available, the difference between the two groups could not be shown to be significant. The average operation time of UKA and TKA is 68.8min and 81.5min(p<0.01). Blood drainage after operation had a significant difference between the two groups (p<0.01). Seven cases of UKA were converted to total knee arthroplasty - all of them within the first 2years of starting the procedure and all of them in relatively young patients. From the study we concluded that mobile bearing UKA can obtain similar clinical effect with TKA by surgeons who have the adequate training and experience. After the learning curve UKA should be considered the primary treatment option for unicompartmental knee arthritis.