What Causes Recurring Fevers After Broken And Injured Leg?

Hi. 4 months ago my husband badly broke his leg and badly cut the other. He had to wait 2 weeks for an operation because he ran a high fever of shaking and sweating so much the nurses lied him on towels. Blood tests shown NO infection. Since then he has had 2 more fevers of the same nature, mostly with no "cold like" symptoms, although this time he is coughing up a lot of from his chest. Is there anything to be causing these recurring fevers. Also no other member of the family has these fevers in the sense of a flu going round. thanks x