Former world number one Martina Hingis may be forced to quit tennis due to a serious foot injury, the doctor treating her indicated today.
"We have to see how far the inflammation in the joints has already led to arthrosis," Dr Heinz Buhlmann told the private Swiss station Radio 24.
"We cannot yet say how sensible it would be for her to continue her career or whether to end it would be advisable on medical grounds."
Arthrosis is another name for osteoarthritis.
Buhlmann, who is treating 21-year-old Hingis in a Zurich clinic, said she is suffering from pain in the joints of her left foot, left knee and left hip.
Buhlmann, who has yet to make a firm diagnosis, warned that long term inflammation could have led to joint damage, which would force Hingis to end her career.
Melanie Molitor, Hingis' mother, confirmed that her daughter is undergoing tests in Zurich and speculated that any joint damage may have been caused by the shoes she wore from the age of 11 until three years ago.
Hingis is still involved in an ongoing legal battle with shoe manufacturers Sergio Tacchini after alleging that their shoes damaged her feet.