More about loose kneecap – patella instability

Loose kneecap is a common condition. In the upcoming text and in the subpages, you can learn more. However, you don’t need to know all of this to be treated. However, it is recommended to do some reading to make sure you are thoroughly examined and receive the right treatment.

Dislocated kneecap

Have you had bad luck and dislocated your kneecap? You can hope that it’s a once-in-a-lifetime event and that you won’t have any problems afterwards. You may also be unlucky that it happens repeatedly. In fact, we now know that those who have dislocated their kneecap once have just as many problems as those who dislocate it repeatedly. If your kneecap has been dislocated more than once, it will tend to dislocate again and again. For some, having a loose kneecap is quite debilitating, but the good news is that it can be addressed.

Symptoms

The kneecap will typically be loose when you change direction suddenly. This can be in sports, dancing and sometimes just when you turn. Your kneecap doesn’t always pop out completely. Sometimes it just feels like it’s on its way out. For example, this can be experienced when walking on a loose and uneven surface. If it’s really bad, concentrate on keeping your kneecap from dislocating when squatting, getting in and out of a car or having sex. It’s not uncommon if you find that your quality of life is significantly affected because your knee is keeping you from many activities. Sometimes the disorder will also be accompanied by pain in daily life.

There are many names for this term, and here you can read much more about: Loose kneecap or kneecap slipping or kneecap slipping or kneecap dislocation or knee dislocation 

Facebook page about loose kneecap – here

If you are taking out a Danish health insurance, be aware that some insurance companies do not cover highly specialized treatment. This does only apply for Danish insurances. Normally when you come from abroad there is no problems. However, this is only relevant if you are undergoing trochleoplasty  

Why you?

It is important to find the cause of why your kneecap has become loose, as treatment should correct the cause or causes, as there can be multiple causes. As a minimum, you should undergo a thorough examination by the surgeon and an MRI scan before surgery is scheduled. This can identify one of the four most common causes of a loose kneecap and treatment can aim to correct what’s wrong.

The many myths

There are many myths about loose kneecaps. One myth is that you outgrow it. Often the discomfort is worst in your teenage years, and then you can learn to avoid activities that make your kneecap feel loose. However, some people don’t want to “live with it” and choose to undergo surgery in order to have an active life. Joints tend to become less supple over the years and this can help keep the kneecap in place.  

It just needs to be trained away

The next myth is that you just need to train it away. This is partially true because some people can probably avoid surgery by learning how to use the knee correctly with a physiotherapist and by strengthening the thigh and hip muscles. A specialized kneecap stabilizing brace (such as the DJO Tru-Pull) can often help you support your kneecap. Scientific evidence so far suggests that physiotherapy cannot prevent kneecap dislocation.

It just needs surgery

The next myth is that it’s easy to treat a loose kneecap with surgery. Unfortunately, some patients are operated on without the surgery working as intended. This is because the reasons why your kneecap has become loose have not been addressed. As mentioned, it is therefore important to find the cause of the kneecap dislocation with an MRI scan. Then your surgery can be tailored to you, and the surgery will be effective.

It’s hereditary

The next myth is that it’s hereditary, and in fact this is often the case. Sometimes a kneecap can be traced back several generations.

Too bad Sonny boy

The next myth is that you just have to live with the discomfort if you’ve had surgery and it didn’t work as intended. Unfortunately, it’s a type of condition where quite a few patients are operated on with an inappropriate method. This may explain why it hasn’t helped you or may have even worsened your condition. Knowledge about the cause and treatment of a loose kneecap has changed radically in the last few years.

Why does the kneecap dislocate?

There are several causes of a loose kneecap. The most common is that the groove (called the trochlea) that the kneecap is supposed to run in when the knee bends is not deep enough. If the kneecap is not held in place in this groove, the kneecap will tend to be loose. Among those who have dislocated their kneecap and have a flat guide groove (trochlear dysplasia), 2/3 of them will experience dislocation of the kneecap again. If you have a normal guide groove, the risk will only be less than 1/3rd. The reason why the groove is flat is because, for unknown reasons, it is already filled with too much bone under the cartilage at birth and therefore the groove lacks external support for the kneecap. See the images below. There’s a whole page on the causes – check it out click here

3D reconstructions of a normal knee on the left and a knee with a flat groove on the right.

MRI scan of two different knees, showing cross-sections of a normal knee on the left and a knee with a flat groove on the right.

Other causes of a loose kneecap 

However, there are other causes of a loose kneecap than a flat guide groove. The second most common cause is Patella Alta, which means too high a kneecap. If you want further explanation, read more under Loose Kneecap.

What happens when the kneecap pops out?

The first time the kneecap pops out, a ligament on the inside (called the Medial Patellofemoral Ligament – MPFL) is torn. As you may know, it is associated with a lot of pain and swelling of the knee. Sometimes the accident causes some cartilage to tear in the knee. If a larger piece of cartilage is torn, surgery may be required to put the cartilage back in place or remove the loose piece of cartilage.

How bothered am I?

For those who suffer from persistently loose kneecaps, there are large individual variations in how much it bothers them. We now know that having a loose kneecap often reduces quality of life more than having an ACL injury. For some patients, it is severely debilitating and they stop having an active life. However, there are questionnaires that can help you and your surgeon determine the extent of your problem. See examples of a questionnaire here. As mentioned, not all kneecaps dislocate (dislocate) again, but some continue to feel like they are about to dislocate (subluxate) again.

Treatment of a loose kneecap

Until recently, the treatment when your kneecap first dislocates has been to immobilize your knee with a brace that limits the movement of your knee. The idea was that it gave your knee some scar tissue in the medial ligament, the ligament that helps prevent the kneecap from popping out on the outside. However, new research that I have participated in has shown that it actually seems to be better to go without a splint.

I would recommend that you re-train with a physiotherapist, who will teach you how to move your knee correctly. You also need to strengthen the thigh muscle that helps hold the kneecap in place and train your mobility. If this treatment does not provide sufficient stability to the kneecap, you may consider a patella stabilizing brace or surgery, read more about surgery here: MPFL reconstruction – tibial plafond relocation – Trochleoplasty

Releasing the outer ligaments by mistake – lateral release

Some patients have mistakenly undergone lateral release and the kneecap tends to bounce inwards. The condition can be very troublesome. The solution is reconstruction of the external ligament using the ileotibial tract – a simple operation similar to MPFL reconstruction.

I have a J-sign

What does it mean to have a positive J-sign? A J-sign is a “bad sign.” It means there is an underlying issue where something is structurally abnormal, and it could be trochlear dysplasia, patella alta or an inward-tilting kneecap. If you have a positive J-sign, it’s important to identify the cause. This is because if you simply stabilize your patella through a so-called MPFL reconstruction , there is a high risk that your patella will become loose again after some time.