Often referred to as patello-femoral pain (PFP), Runner's knee is caused by the patella (knee cap) tracking unevenly through the groove at the lower end of the femur.
Symptoms include a persistent ache in the kneecap, or a sudden, stabbing pain in the knee while running. Typically this will reduce or stop when you rest. In many cases the joint may look normal (no swelling), although there are other physical symptoms, including:
- Weak vastus medialis muscle
- Knock knees (genu valgum)
- Twisted tibia
Diagnosis is based on a physical examination, which might include the Clarke's test, (pulling the kneecap towards your toes while you straighten your knee), a look at the wear pattern on your running shoes, or even analysis of your running gait.
You can also have what is termed a 'sunrise' x-ray of the flexed knee, which will show if your patella is abnormal, roughened or displaced.
As in most cases the problem can be attributed to weak vastus medialis muscles, the number one treatment is physiotherapy to strengthen these muscles.
You can self treat by practicing using the muscles to lock the knee in a straight leg position. This causes the vastus medialis to fire. Straight leg raises will also be extremely useful.
In most cases you can return to running without further problems once the muscles have been strengthened.