Objective To analyze interface stress of cemented tibial prosthesis platform and determine the interface stress damage area, so as to provide references for stress failure of tibial platform in clinical single condylar replacement. Methods The full cycle gait was simulated by human dynamics software to obtain the load-bearing condition of knee joint. A complete model of the knee joint was established by medical imaging and three-dimensional (3D) reconstruction software, and unicompartmental replacement was performed. The distribution of interfacial stress of tibial prosthesis platform after single condylar replacement was analyzed by finite element method. ResultsIn gait, force and angle of the knee joint changed periodically with time, a cycle lasted 1.3 s, and the peak of knee joint resultant force was 760 N. The maximum shear stress of the interface was 11.82 MPa and the maximum tensile stress was 6.849 MPa, both occurred at inner front end of the corner of prosthesis cement interface. The maximum interface stress of titanium alloy prosthesis was lower than that of stainless steel prosthesis. Conclusions The decrease in elastic modulus of prosthesis can reduce the maximum principal stress at the interface. Considering the interface stress, titanium alloy prosthesis is better than stainless steel prosthesis. The area of tibial prosthetic platform interface damage is mainly at the medial anterior and posterior corners and lateral middle ends,so improving the ability of prosthesis cement bonding in this area can prevent the loosening of tibial prosthesis of unicompartmental knee joint.The findings have practical implications for the prevention of tibial prosthetic platform loosening after unicompartmental knee arthroplasty in clinic.