To analyze the long-term survival rate of Oxford medial unicompartmental knee arthroplasty, and to investigate the management and prevention strategy for complications.

A retrospective analysis was performed on 435 patients (515 knees) with anteromedial osteoarthritis of knee treated by Oxford unicompartmental knee arthroplasty in the Department of Orthopedic, the General Hospital of Jinan Military Commanding Region, from April 2007 to October 2016. There were 150 males and 285 females, whose mean age was (61±8) years. The mean body mass index (BMI) was (24±3) kg/m², range: 19~36 kg/m². The knee range of movement (ROM), Knee Society score (KSS) and Oxford knee score (OKS) were used to evaluate the clinical efficacy. All the postoperative complications were recorded, and Kaplan-Meier survival analysis was used to evaluate the survival rate of the prosthesis. The ROM, KSS score and OKS score were analysized by paired t test.

The average follow-up time was (5.2±1.8) years. The preoperative KSS score was (59±10), and the postoperative KSS score was (93±8)(t=-2.586, P<0.05). The preoperative OKS score was (24±8), and the postoperative OKS score was (43±5)(t=-2.056, P <0.05). The preoperative ROM of knee was (111±5) °, and the postoperative ROM of knee was (127±8) °(t=-2.334, P <0.05). The total survival rate of the prosthesis was 92.2%.There were 15 cases with complications(2.9%): six cases of polyethylene insert dislocation (1.2%); one case of delayed deep infections (0.2%), treated with revision of total knee arthroplasty; three cases of femoral condyle prosthesis loosening (0.6%), including one case of dislocation at the same time, of which two cases were treated with revision of unicompartmental arthroplasty and one case was treated with revision of total knee arthroplasty; two cases of recurrent aseptic joint effusion (0.4%), treated with joint drainage and physiotherapy; two cases of intra-articular free bodies(0.4%), treated with arthroscopic surgery; one case of unexplained pain, recovered after conservative treatment; one case of intraoperative injury of anterior cruciate ligament (0.2%), treated with ligament suture during operation and the hinge brace was fixed for four weeks, and the function of the knee joint recovered.

Oxford medial unicompartmental knee arthroplasty is the best treatment for antero-medial osteoarthritis of knee, of which the clinical efficacy is reliable, and the incidence of complications is low. Mature surgical procedures can ensure good results of UKA and reduce the incidence of complications. The causes and types of complications should be carefully analyzed and appropriate treatment should be given.