What was the cause of Gregory House’s chronic leg pain in House M.D.?

Gregory House’s chronic leg pain was caused by a quadriceps muscle infarction.

In the show’s backstory, House suffered an infarction in the quadriceps muscle of his right thigh. The resulting muscle damage left him with permanent pain and a limp, leading him to use a cane. He eventually underwent surgery that removed damaged muscle tissue, but the procedure did not restore normal function.

The condition is unusual because an infarction is tissue death caused by loss of blood supply, more commonly discussed in connection with organs such as the heart. House’s case made the injury central to his character and helped explain both his disability and his reliance on pain medication.

The injury is sometimes incorrectly described as a simple knee problem or a broken leg. Those descriptions miss the specific diagnosis established in the series: a quadriceps muscle infarction in the thigh.