Mijza'ah bin Zahir (may Allah have mercy on him) narrates from a man among the People of the Tree whose name was Sayyiduna Uhban bin Aws (may Allah be pleased with him): he felt pain in his knees, so when he prostrated he would place a pillow under his knees.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3677