Narrated by Ali ibn Ibrahim, from his father, from Ibn Abi Najran, from Asim ibn Humayd, from Muhammad ibn Muslim, from Abu Ja'far عليه السلام:
I asked Imam عليه السلام about a man whose hand and foot are amputated (regarding his ablution). Imam عليه السلام said: "He washes them."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 382