Carlos, 75, has had four operations for a hip replacement, a benign tumor and an operation following a fall while hunting, thinkSPAIN reported.
Carlos' reputation has been in question since he was involved in elephant hunting and was photographed next to a dead one, thinkSPAIN said.
The royal family has also been drawn into controversy over an investigation over Carlos' son-in-law's possible involvement in a money laundering case at the Noos Institute, which he headed.
But Carlos' son-in-law, Inaki Urdangarin, has denied that the royal family was involved in the case in any way, thinkSPAIN said.
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