Which medical condition causes Gregory House's characteristic limp in House M.D.?

Gregory House's characteristic limp is caused by an infarction of the quadriceps muscle in House M.D.

The infarction damaged muscle in House's right thigh after a clot blocked blood flow. Because the tissue was not restored promptly, part of the quadriceps became necrotic. House ultimately underwent a risky surgical procedure to remove the dead muscle rather than lose the entire leg, but the damage left him with chronic pain and a permanent limp.

The injury is central to House's characterization. He uses a cane, takes the painkiller Vicodin, and often behaves as though his physical suffering justifies emotional distance or rule-breaking. The story also explains why his pain is both a medical problem and a recurring source of conflict with colleagues.

Viewers sometimes describe the condition loosely as a leg injury or assume it was a fracture. Neither is the specific diagnosis given by the series. Multiple sclerosis and an Achilles tendon tear are also different conditions. The canon identifies an infarction affecting the quadriceps muscle.