Kneecap Pain

(Patella Femoral Syndrome or Chondromalacia patella or Lateral tracking patella syndrome.)

What is it? Why do you get it?

The kneecap has a V shaped outcropping on the back of it and the thighbone has a V shaped groove on the front of it. The two muscles on the front of the thigh should pull the kneecap straight up and down the groove when everything is working well. The underlying problem is all about the physics of the angle of pull of those two muscles. In certain circumstances, the outside muscle can pull a lot more strongly than the inside one and so ends up doing a lot of work and getting stronger. The inner one can t contribute as it should and rests when it ought to be working. When this happens, the kneecap runs off course in its groove, irritating and wearing away cartilage on one side. The podiatrist will check your knee for this sign and you will be able to see it for yourself.

Pain is usually described as being on the edges of the kneecap or up and under it. Often there is a feeling of fullness below the kneecap that comes from the swelling inside the joint. At times, a piece of tissue called the retinaculum that holds the kneecap in place can cause pain around an inch below the kneecap off the inside edge.

Who gets it?

In females, the hips are wider than in males and the thigh bone has to angle in towards the knee. This makes a line drawn between the upper and lower attachments of these muscles pass to the outside edge of the kneecap. The kneecap is contained within the tendon of these muscles and when they contract, there is a large force pulling the kneecap off course in its groove. In pronators (people whose feet roll in), not only are the feet affected but the whole leg will rotate inwards (towards knock knee). This has the same affect as described above for females. This means that men can experience these effects but also that women who pronate are likely to be the worst sufferers. The angles on the pictures on the previous page will help explain this.

Treatment

Two things are necessary to treat this problem. In the short term, great reduction in pain can be achieved within 10 days by strengthening the weak inside muscle. Avoid doing big gym style knee extensions as this will force the strong muscle to do the work and get stronger still. The correct exercise is a subtle one but very easy to do. You will be shown exactly how at your consultation. In the longer term, shoe inserts called orthotics are usually required to stop the leg from rotating inwards. This rotation is quite difficult to control, needing a perfectly fitting orthotic and for this reason, one-size-fits-all insoles from sport shops or chemists are not suitable.

What happens without treatment?

Without treatment the kneecap cartilage will wear unevenly (pictured below). Ultimately this is what brings about a good proportion of knee replacement surgery. Cartilage that wears unevenly can wear into a distinct ridge, resulting in a clicking sound as you walk. Tiny pieces of cartilage that are ground off stay floating in the joint fluid and make crunching noises as you walk upstairs. Neither of these will go away with time, even when your knee corrected via foot orthotics, as the small pieces remain in the fluid.