Is it permissible for a physically challenged imam, whose foot has been amputated and who wears a prosthetic foot, to lead people in prayer?

A person who is unable to perform the pillars of prayer is one who cannot stand or prostrate on the ground, and so forth. The ruling on his leading the prayer (imamate) is a matter of scholarly disagreement. However, if he fulfills the pillars perfectly and the shortness of his foot does not prevent him from bowing, standing, and prostrating, then his imamate is undoubtedly valid.