Background: The most popular unicompartmental knee replacement(UKR) prosthesis to treat medial compartment
osteoarthritis (OA) is the Oxford knee (OUKR). This prosthesis now has cemented and cementless fixation options.The fixation of the new cementless implants has proved successful with significantly reduced radiolucent lines compared to the cemented prosthesis in the designer series. Unfortunately, some studies have reported tibial component subsidence as a specific complication to the cementless design. Aim of the Work: This study aims to review the fixation and clinical outcomes of the cementless prosthesis. We report the incidence of radiolucent lines associated with both cementless and
cemented tibial prosthesis. More importantly, to study the incidence of tibial component subsidence. Materials and Methods: This is a prospective study of a consecutive series of the Oxford medial UKR. All patients had bone on bone arthritisfulfilling the criteria for anteromedial OA. All patients received cementless femur implants. The majority of patients received cementless tibial implants. Cemented tibial component was only used in elderly patients where the tibial metaphyseal bone was found potentially weak intraoperatively. Fluoroscopy-aligned radiographs were obtained post-operatively and at one-year.Radiolucent lines and subsidence were evaluated. All patients completed the Oxford knee
questionnaire (OKS) at one-year follow-up. Results: A total of 68 knees implanted in 59 patients completed the study. Fully cementless medial OUKR (n=61), and cemented tibial with cementless femur (n=7). The mean age was 67.5 years. Two patients required revision to TKR. The cemented design had higher incidence of radiolucent lines. One patient had Cementless tibial component subsidence. The median OKS was excellent in both groups. Conclusion: Both designs of the OUKR are valid treatment optionswith excellent OKS. Radiolucent lines are less frequent with the cementless design buttibial component subsidence and fracture have a higher incidence compared to the cemented prosthesis.