The effect of different interference fits on the primary fixation of a cementless femoral component during experimental testing

Cementless femoral total knee arthroplasty (TKA) components use a press-fit (referred to as interference fit) achieve initial fixation. A higher fit could lead superior fixation, but it also introduce more damage the bone during implantation. The purpose of current study was investigate effect on micromotions and gap opening/closing at bone-implant interface. Experimental tests were performed in six pairs cadaveric femurs implanted with using low 350 ?m high 700 ?m. specimens subjected peak loads gait squat, based Orthoload dataset. Digital Image Correlation (DIC) used measure different regions interest (ROIs). Two linear mixed-effect statistical models created dependent variables. ROIs, loading conditions, implant designs independent variables, cadaver random intercepts. results revealed no significant difference between two implants for (p = 0.837 p 0.065 squat), nor 0.748 0.561 squat). In contrast, differences found most ROIs both variables < 0.0001). Additionally, deformation fit. Changing either or did not affect primary stability TKA component. There be an threshold beyond which fixation does further improve.