What medical condition caused Gregory House to need a cane in House M.D.?

Gregory House needed a cane because of an infarction of his quadriceps muscle.

The infarction cut off blood supply to muscle in his right leg. Because the condition was initially misdiagnosed, the damage progressed, and House ultimately underwent surgery that left him with chronic pain and a distinctive limp.

This history explains several permanent features of the character: his cane, his dependence on Vicodin, and his hostility toward doctors who fail to recognize unusual diagnoses. The leg injury is not simply an unexplained disability added for visual effect; it is part of House’s backstory and medical identity.

The show gradually reveals details of the injury through flashbacks and dialogue. A common mix-up is to describe it as a broken leg or a general muscle strain, but the specific diagnosis is a quadriceps infarction.