Patellar Instability Overview

Patellar Instability Overview

A lax kneecap is a common disorder, and in the following text and subpages you can learn about this problem, but naturally it is not necessary for you to know everything there is to know in order to get treatment. (so warning - this is nerdy)
Symptoms of unstable kneecap

For some patients with kneecap laxity the kneecap will goes out once and they will experience no further problems. Others, however, may go on to experience repeated dislocations. If the kneecap has gone out more than once, it will have a tendency to out again and again, and then things may become quite disabling. The problem can occur while doing activities, like changing direction such as in sport or dancing, while for others the kneecap just seems to go out without much provocation, and this can happen while walking on uneven or slippery surfaces. In some of the worst cases you need to concentrate on avoiding the kneecap popping out the groove while kneeling, jumping in and out of a car or during sexual activity. Quality of life can be significantly affected, since a lot of simple daily activities must be avoided. Sometimes the disorder also causes pain during daily life. It is very important if you are going for surgery to rule out what cause your instability, since the surgery should correct the identified abnormality (or abnormalities, since there may be several factors involved).

Why me?

It is very important to find out why your kneecap dislocated, since there are so many treatments and in order for you to have the right one, this have to be examined. This is rather complicated and I have made a site only for explaining this in order for you to ask you surgeon the critical questions - click here

The many myths

Many myths exist about loose kneecap, and one is that you will grow out of it. Mostly this disorder is worse during the teenage years and then you learn to be more cautious and reduce your level of activity. There is furthermore a tendency for the joint to get less flexible as you age and this helps the kneecap to stay in the groove. So many grownups do not actually grow out of the condition - they just learn to avoid the activities that provoke the dislocation.

It is just going to be trained away

Another myth is that the disorder just needs to be trained away. This is only partially true. Some may perhaps be able to avoid surgery by learning to use their knee in a more correct way via physiotherapy and by strengthening the quadriceps and gluteal muscles. A special brace that supports the kneecap (for example DJO Tru-Pull) can stabilise the patella. There is yet no scientific documentation that say that physiotherapy can prevent further dislocations

Easy to treat - you just need a MPFL reconstruction

The next myth is that surgery can easily treat the disorder. A significant number of patients undergo surgery only to experience that the surgery did not work as intended. As previously mentioned, is of importance to explore the reason why the kneecap dislocates - for example by MRI - so that the surgery can be individualised and thereby work efficiently.

It is hereditarily

The next myth is this disorder is inherited. Actually this is true in several cases, and sometimes a dislodged kneecap can be traced back several generations.

Sorry you surgery did not work

A further myth is that if you had once undergone surgery, and it did not work, that you just need to live with your symptoms. Unfortunately this is a disorder where many patient have undergone surgery using an insufficient method, and this explains why it did not help or maybe even worsened the situation. Knowledge about this disorder has changed radically over recent years and if the right surgery is done, there is a very good chance for your knee to become significantly better.

What happens when the kneecap dislocate

When the kneecap jumps out it is naturally a very unpleasant experience and often the kneecap has to be manipulated back at the emergency department. The first time the kneecap dislocates, a ligament on the inner side is torn (this is called the Medial Patellofemoral ligament - MPFL). Such an injury causes a lot of pain and swelling and sometimes a fragment of the knee cartilage is loosened. In some cases a loosened piece of cartilage requires surgery to fix the piece back in place or to remove it.

How much will I get troubled?

For those troubled by a continuously loose kneecap there will be a huge variability how much distress this actually causing. However questionnaires have been developed to help both patient and surgeon to elucidate the extent of the problem. Please see an example of a questionnaire here. As previously mentioned is it not always that the kneecap jumps out again, but still it can be troublesome since the person may experience that it nearly jumps out (which is called subluxation).

The treatment of loose kneecap

The first time the kneecap goes out, the treatment is likely to just consist of rest, ice, compression and elevation (RICE), while allowing full weightbearing and full range of movement. In past years a brace for support and immobilisation was generally used, but recent research has shown that it does not have any real impact. If the knee does not get the stability wanted and the kneecap continuously is feeling loose a kneecap stabilising brace or surgery should be considered. Physiotherapy has also been an important part of the treatment in improving muscle balance, but studies have not really demonstrated that it has a positive effect on the patellar looseness itself. Please read more about surgery here; MPFL reconstruction - Elmslie-Trillat surgery - Trochleoplasty

The many names for unstable kneecap

The condition of a loose kneecap has many names and here you can learn more about: dislocating kneecap, kneecap out of its groove, kneecap out of its socket, kneecap malalignment, slipped kneecap, jiggly kneecap, unstable kneecap, recurrent patellar instability, episodic patellar instability, luxating patella, unstable patella...


The condition of a loose kneecap has many names and here you can learn more about: Dislocating kneecap, kneecap out of groove, kneecap out of socket, kneecap malalignment, slipped kneecap, jiggly kneecap, unstable kneecap, recurrent patellar instability, episodic patellar instability, luxating patella, unstable patella