The patella (knee cap) is the bone which moves over the front of our knees. It transmits all the force of the quadriceps muscle which extends the knee enabling us to climb stairs or rise up from a chair. It has a cartilage surface which can be damaged or worn in which case anterior pain results.
Cartilage damage can be due to a chronic condition called mal-tracking when the patella does not sit squarely in its groove. This usually is the result of minor alignment changes dating from birth. Sometimes if the groove is very shallow the patella may dislocate with simple twisting movements.
In some people, the problem is not instability but chronic irritation in the patello-femoral (knee cap) joint. This can create an intractable problem of pain in the front of the knee. The pain is worse while climbing or descending stairs.
Patella maltracking is usually evident on clinical examination. It is confirmed by a plain x-ray and MRI scan.
When this pain arises due to patella dysfunction, physiotherapy is often the treatment and strengthening the quads and stretching them appropriately can improve these symptoms quite significantly. If this does not help the pain of the chronic maltracking or the patella remains unstable, a corrective operation called a tibial tubercle transfer is required.