Salim bin Abdullah (may Allah have mercy on him) narrates from his father (may Allah be pleased with him) that the one who is prevented (muhsar) does not exit ihram without performing tawaf of the House and the sa'y between Safa and Marwah. If he is compelled to wear clothes that he cannot do without, he may do so, but he must pay its ransom (fidyah).
Imam al-Shafi'i (may Allah have mercy on him) said in Kitab al-Manasik: This refers to the one prevented by illness, and Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10093