Sayyiduna Ali (may Allah be pleased with him) used to cut off the foot and leave the heel, so that he could lean on it. Sayyiduna Ali (may Allah be pleased with him) distinguished between cutting the hand and the foot: he would cut the hand at the joint and cut the foot from its middle.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السرقة / 17253