Dislocated kneecap or dislocated patella is not that common. It can occur of course, but it isn't very common. What you have is a situation where the quadriceps tendon, which is basically the end of your quadriceps muscle, forms a tendon and it attaches to your patella or your kneecap. Then from there you have a tendon that runs from your kneecap down to your tibia, and that's called your patellar tendon.
We're mostly concerned about your quadriceps tendon. There is a groove inside your bone – it's called the femur – and that allows the tendon to glide in and out very well. But if there's a dislocation, that tendon actually pops out of that groove, and the response is immediate pain and swelling. It's terrible.
What's unique about this injury is that once you've had it, it is imperative that you try to figure out a way to rest your leg, and by resting your leg we're talking about resting it in extension. If you see a doctor, they may even prescribe some sort of an immobilizer for you to keep your leg in extension, meaning keep your knee straight. This will allow the tendon to heal and heal a little bit quicker, and it can also help just with the swelling issue as well, just kind of keeping your leg free of motion and your knee free of motion.
So the first step is always going to be to rest it and keep it immobilized. Three to five days is usually recommended.
After you've gotten over this period of time, you are then going to start exercising, of course, and the first safest ones are going to be some quadricep exercises, but quadricep exercises where you're not bending and straightening out your knee over and over again. So the classic one are called quadricep sets for quad sets, and it's an isometric technique that you can use basically on the floor or on your bed.
Typically, I tell patients to start by just getting on the floor and having your leg fully straight and just tensing your quad muscle, holding it for a few seconds, and releasing and repeating over and over. Once that exercise has been perfected, you might want to sneak a towel just underneath your knee, and that just puts the knee in a little bit of flexion now. So now you're challenging the tendon a little bit more. You have the knee in a little bit of flexion, and you're still going to try to accomplish the same exercise.
Then from there you might want to move on to a tightening knee exercise and an actual straight leg raise, where you're lifting the leg up into the air, again maintaining your knee in extension. It's crucial those first few weeks.
After about a week or two, when you're starting to get over some of the pain and you're able to function a little bit better, it might be a good idea to start cycling. Cycling is a great exercise to start doing at this point because you're getting the range of motion from the peddling, but you're also not doing extreme ranges of motion. So it's safer, and then of course you're getting your quad and hamstring workout from the bike.
So the first step is definitely rest and specific rest where you're keeping your knee in extension, followed by some quad exercises and then followed by some cycling. It's a tough one. It's tough to recover from. There's a lot of scar tissue formation. So you have to be careful with that. It's a pretty manageable problem though for years to come. It doesn't rear its ugly head down the line like other wear and tear injuries.