Why does Hugh Laurie/Dr. Gregory House have a limp in "House M.D." (T.V Series)?

Caused by an infarction in his quadriceps muscle. When in hospital he belived that he should wait and see and his wife and his doctor thought that they should operate as if they waited he may die. His wife gave permission to operate against his wishes and the operation caused irreperable damage to his leg. If they had waited it would have been better. That's also why him and his wife divorced.