CONDITION - Patellar Instability

Patellar Instability (Dislocations, Subluxations)
Patellar instability means any problem that can cause your knee cap ("patella") to dislocate, or slip out of socket. The patella is probably the bone that is the most commonly dislocated in the body.

Dislocation of the patella is very common. It is particularly common in teenagers and women (although not uncommon in men as well). There are different ways to classify this problem.

Classification by trauma

• Traumatic. This means that there was some kind of accident that caused this problem. For example, a sudden twisting of the knee caused the kneecap to come out of socket. This is common in women and men. Usually, a ligament is torn when this happens. Sometimes the ligament never completely heals back properly, and people have recurring problems.
• Atraumatic. In this case, there was no specific injury before the kneecap started coming out of socket. This is the type of instability that is more common in women. This can happen because the person is "loose-jointed". Note: you can be loose-jointed in your knees and not anywhere else. Also, another common problem is that the kneecap is misaligned (i.e., tilted or shifted) and that puts you at risk for instability.

Classification by amount of instability
There is a wide range of patellar instability, including:

• Pain only. When the kneecap is "trying" to dislocate, but never actually does it, sometimes it can just cause pain around the kneecap (similar to chondromalacia). This can sometimes be described by doctors as "excess lateral pressure syndrome" or "lateral tracking". The pain is usually on the outside of the kneecap, and often it is tender to the touch in this area. Sometimes the pain is made better by pushing the kneecap inwards with your finger. Sometimes taping the kneecap in this position can help with the pain (many athletic trainers will do this for their athletes on occasion; unfortunately it is just a temporary cure).
• Subluxations. This means that the kneecap manages to get out of the socket partially, then comes right back into place. Often people will complain of pain and clicking. These people will often feel their kneecap shift around as well.
• Dislocations. This is the most severe form of patellar instability. The kneecap pops out of socket (usually laterally, or to the outside) and gets stuck out there. The first time this happens, many people end up going to the hospital to have it put back in place. If it becomes a recurring problem, often these people learn how to put it back in place themselves.