A form of OSTEOCHONDROSIS involving the tibial tubercle – the growing point of the TIBIA. It occurs around PUBERTY, mainly in boys, with painful swelling just below the knee, worse during and after exercise. A limp with increasing limitation of movement of the knee-joint develops. The disease usually clears up without treatment but if pain is troublesome, physiotherapy or immobilisation of the knee-joint in an orthosis (see ORTHOTICS) may be necessary.