In House, M.D., which disease causes House's chronic leg pain?

In House, M.D., an infarction of House's quadriceps muscle causes his chronic leg pain.

The infarction cuts off blood flow to muscle tissue in House's right thigh. Although the immediate damage is treated, the resulting pain and disability become permanent features of his life. House walks with a cane and relies on pain medication, especially Vicodin, during much of the series.

The condition is not simply a bad knee or a broken bone. The show's backstory explains that House delayed surgery after suffering the infarction, allowing the muscle damage to become severe. This is why the injury has such a lasting effect on his gait and personality. The detail is often simplified in summaries, but the canonical diagnosis is an infarction of the quadriceps muscle.