What fictional leg injury causes Gregory House’s chronic limp in House M.D.?

Gregory House’s chronic limp is caused by a muscle infarction in his right thigh in House M.D.

The injury occurred when a blood clot cut off circulation to the quadriceps muscle. House delayed treatment because he believed another doctor, Stacy Warner, understood his condition, but the damaged muscle eventually required surgery. A large portion of the quadriceps was removed, leaving House with permanent pain, weakness, and an altered gait.

The injury explains several defining elements of the character: his cane, his reliance on pain medication, and his intense fear of worsening pain. The show reveals the backstory gradually rather than presenting it in the opening episode. The condition is sometimes misremembered as a broken leg or a simple orthopedic injury, but the specific diagnosis is muscle infarction caused by an occluded blood vessel.