Dislocation of your kneecap (patella) is a common knee injury that occurs when the patella bone slides out of the groove on the thigh bone that it sits in.
This happens when force is applied from an external source or with sharp movements of the knee combined with a local weakness of the surrounding tissues.
If the force applied to the knee is great enough it will force the kneecap to dislocate and even ligament rupture can occur.
Most Patella dislocations will self relocate when the knee is straightened but some may require help from a medical professional.
Recurrent patella dislocations are very common and there are other factors such as biomechanics and strength involved – which we will explain further in to the article.
Anatomy of the Kneecap
Lets take a look at the anatomy of the kneecap region:
Femur
This is the thigh bone and the largest bone in the human body. This is the bone that the knee cap sits on to. There is a small groove on the end of the femur which is called the trochlear groove and this is key for the patella. The trochlear groove is a small indentation which should fit the patella perfectly and allow the patella to sit in securely and give it a track to slide up and down. In some individuals the groove will not be as deep and this can cause instability of the patella sand increase risk of dislocation.
Patella
The kneecap, is a small triangular bone which sits on the end of the femur to form the patellofemoral joint. When the knee bends and straightens, it slides up and down. On the back of the kneecap there is smooth cartilage which cushions the movement and allows it be pain free.
Quads
This is the crucial muscle group that helps to secure the patella. The quadriceps are made up of 4 main muscles which are the vastus medialis, vastus intermedius, vastus lateralis and rectus femoris. The quads help to mainly extend the knee and also assist with hip flexion. The key reason they help with kneecap security is the quads tendon attaches to the patella and the other tendon attach below the knee. The stronger the quads – the more secure the knee cap will be.
Patella Ligaments
The knee cap is held in place by patella ligaments which sit either side of the kneecap. This is the medial and lateral patellofemoral ligament and they help to keep the kneecap in place and so aim to prevent dislocation. With recurrent dislocation, ligament tears and ruptures can leave the ligaments requiring reconstruction.
Symptoms of a Dislocated Kneecap
Dislocation of the knee will come with many symptoms, such as pain and swelling in the early stages. When the injury first occurs it is typically painful and in some cases support from a medical team is required if the kneecap cannot be self reduced.
If pain is extreme, an ambulance or emergency service may be able to provide pain relief whilst they relocate it. This is simply done by straightening the knee and applying gentle pressure to the kneecap and gently pushing it back in top the trochlea groove.
Swelling can be present for 1-2 weeks whilst the knee heals and irritation reduces.
Pain in the local area of the kneecap is common, and again this can be present for a few weeks. With pain comes weakness and dysfunction of the knee. Inability to generate force and absorb load will be a big factor after injury – this means that exercise and vigorous activity will be difficult.
Loss of range of motion in the can be common due to the elevated pain levels experienced.
Knowing how to manage patella dislocation is key in order to speed up your recovery.
Treatment & Rehabilitation for a Dislocated Kneecap
Get some help from someone who deals with sports injuries, such as a physiotherapist.
There may be a need to refer on to an orthopaedic specialist as if there has been complete rupture of the patella ligaments, it may require surgical management.
Most patella dislocation will not require this level of intervention.
A good knee brace may be a useful addition for patella dislocation management. There are specific knee braces which relieve pressure on the kneecap and have a hole at the front which reduces pressure on painful knees. This is also a great way to reduce knee swelling.
Pain relief will be a great option to help reduce symptoms of pain. This can help to reduce swelling, lower pain and help us to move normally.
Gentle exercises and movement are recommended for the knee. To begin with, non weight bearing, bending and straightening of the knee is advised to allow the patella to move comfortably in its groove without excess pressure. This will also start to reengage the muscles that help to secure it.
Avoiding running and direction changes along with carrying loads in the first 1-2 weeks is to help protect the knee against any undue stress.
Exercises and rehab are key to recovery, take a look at our next section to see what are the first exercises to perform after a patella dislocation.
These exercises should all be performed gently with control.
Aim to do these exercises 2 x per day and perform 3 sets of 10 repetitions. This is just a guide but in the early stages you may even want to decrease amounts if pain is an issue.
These exercises are designed to condition all of the surrounding muscles in the knee that help to secure the kneecap.
Static Quads
This is one of the core knee rehab exercises that will be incorporated in to any rehab program for any knee injury. The quad muscle is important for knee safety and function.
In a long sitting or lying position, simply straighten the knee and force the back of the klnee in to the floor/bed. Hold the contraction for 5-10 seconds, relax and then repeat. This exercise can be performed anywhere at any time, perfect for whilst you are at work or even when relaxing.
SLR
This is a progression of the static quads exercise but now includes hip flexion. In long sitting or lying down, perform exercise number one.
Slowly lift the full leg in to the air about 1 foot – hold for a few seconds and slowly lower down again.
Wall Slide
This exercise is to help you start to place more weight through the knee and prepare you for returning to more intense exercise.
Stand with your back against a wall and simple slide down it, bending at the knees. This essentially is a squat exercise but the security of the wall allows you to remove some of the weight in the exercise.
A free standing squat requires a lot of control from the knee and also strength. Squatting on a recently injured knee can cause discomfort and pain and also lead to imbalance developing.
SLR inside
This stands for a straight leg raise inside. Also known as an adductor raise. In a side lying position, position your bottom leg in front of your other leg.
Slowly raise your thigh upwards to activate your adductor muscles, hold for a few seconds and slowly lower down.
Hip Abduction
Lying on your side and raising the top leg this time. This helps to strengthen the lateral hip which also has an important role for the patella.
The lateral hip blends in to the IT band which runs down the side of the thigh and assists with patella stability but its main job is to control thigh rotation.
Thigh rotation if poorly controlled may be a factor with patella dislocation, especially when changing direction and absorbing force.
Mini Squats
When your knee is reduced in pain and improving – you will be able to start introducing mini squats in to the rehab regime.
Mini squats are a good way to introduce the knee to full bodyweight. A full squat would involve sitting right down and going past the knees. Partial squats ore mini squats simply move through about one quarter range.
Knee Extension Machine
When your knee has settled, returning to exercise should be supported by increased quad strength.
Using a knee extension machine, simply straighten your legs and engage the quads.
These are simple exercises for the early stages – as previously discussed, using a physiotherapist who has experience of this injury would be the best for patella dislocation recovery.
Consider swimming and gentler exercises before progressing to things such as running and contact sports. Recovery from patella dislocation can range from a minimum of 4 weeks upwards of 3 months and longer.
That concludes our guide to patella dislocation and it should be managed, we hope that this has been helpful and given you some good knowledge.
If you think this will help someone that you know then please share this with them. If you have had a patella dislocation, check out our other articles on knee supports to see which ones may help support your recovery from patella dislocation.