I am handicapped; my legs are amputated approximately 15 cm below the knee. Do I have to wash my amputated legs during ablution or should I wipe over my artificial limbs or what should be done in this regard?
May Allah reward you.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

If the amputee still has parts of the amputated limbs, which should be washed during ablution, then he is unquestionably obliged to wash them. However, if the limbs were amputated above the part which should be washed during ablution, then he is unquestionably not obliged to wash them.

If the amputee has his legs severed from the ankles, or the arms were amputated from the elbows, then he should wash the ends of his legs and arms. However, other scholars believed that it is merely recommended to wet the tips of the amputated limbs, which are among the parts of the body that require ablution.

Hence, if your legs were amputated above the ankle joint, as it seems from your question, then you are not obliged to wash the amputated legs or wipe over the artificial limbs; for Allaah The Exalted Enjoined washing the feet up to the ankle for ablution; Allaah The Exalted Says (what means): {And wash your feet to the ankles.} [Quran 5:6] The obligation is removed if the organ involved is removed.

Allaah Knows best.