A prosthetic femoral implant has a stem having a proximal end and a distal end. A circumferential collar is formed on the proximal end of the stem having a proximally facing surface in the form of a circular disc extending radially inwardly and proximally from a maximum outer circumference to a central neck region. The collar has a distally facing surface extending radially inwardly and distally at an included angle with respect to a central longitudinal axis of the neck region of between 120 and 140°. The distal surface of the collar is v-shaped and may be conical in form.