Are knee voltage and Vbe the same?
\$V_{be}\$ is whatever the voltage is between the base (b) and the emitter (e). In some circuits (or states of a circuit) it might be 0 V, in other cases it might be negative. In others it might be equal or a little bit above the knee voltage. It's unlikely to be very much above the knee voltage, because that would result in large currents flowing into the base, most likely damaging the device.