From the study, satisfactory early and midterm clinical outcomes were obtained which was completely comparable to the data reported by other researchers. Krishnan SR, et al. reported the results of their studies, in which 9 patients were treated by the combined operation of UKA and ACL reconstruction, and were followed up for 2 years [
13]. No revision was required in these patients and the mean KSS was as high as 196 points. Similar excellent clinical outcomes were reported by Pandit H, et al. In their study, 15 patients received the combined operation and the mean KSS was 195 points after a FU time of 2.5 years [
21]. To be differently, both of the studies just reported the early clinical outcomes, while in our study the patients were followed up relatively longer time and the satisfactory results were reported with the KSS clinical and function score of 84.5 and 86.9 respectively. In 2012, Tinius M, et al. reported their midterm clinical data with a mean FU time of 50 months [
30], which revealed promising results with the KSS clinical and function score of 84.1 and 83.4 respectively. Comparing with these results, our outcomes were much better. The definite reasons were not clear. It somewhat related to the different prosthesis the two studies adopted. In Tiniu M’s study all patients received fixed-bearing tibial component, while in the current study the mobile bearing Oxford phase III prosthesis was adopted. The mobile bearing could result in low wear and loosening rates according to the literature [
17]. Weston-Simons JS et al. also reported their outcome of combined Oxford UKA and combined or sequential ACL reconstruction in 2012. Fifty-two patients were enrolled the study with a mean FU of 5 years. The OKS and Tegner activity score were improved from 28 and 2.5 to 41 and 3.5 respectively [
31]. In our study, the OKS and Tegner activity score were improved from 31 and 4.4 to 43 and 5.3 respectively. In our study, the patients were more active and all the combined Oxford UKA and ACL reconstruction were done by the same experienced surgeon, and the hamstring tendons autograft were chosen for the patients. While in Weston-Simons JS’s study, patients received simultaneous or staged UKA and ACL reconstruction, and the operations were done by different surgeons. The grafts chosen for ACL reconstruction were also different, including hamstring and bone-patellar tendon-bone graft. Another study about the in vivo kinematics of the combined Oxford UKA and ACL reconstruction showed that the sagittal plane kinematics were nearly normal after combined UKA and ACL reconstruction [
22]. This may also further explain why these knees in our study have good function and do not have tibial loosening in the FU time.