Patella – structure, function, diseases, diagnostics, prevention

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The knee joint is the largest joint in our body. The kneecap is the bone located in front of the knee joint, in the patellofemoral furrow of the femur. Its upper part is attached to the quadriceps tendon and the lower part is attached to the patellar ligament. It helps to give the joints strength and structure that allows you to safely bend and turn your legs. As our knee joint consists of many elements and carries heavy loads, it is susceptible to various injuries and diseases. Some of them may be improved with physical therapy, while others may require surgery.

Turnip – construction

The kneecap is the three-square shape of a triangular bone, with the base facing upwards. It connects to the tibia through the patellar ligament, with the kneecap adjacent to the distal end of the femur thanks to the articular surfaces. The front of the kneecap is a smooth surface that can be easily felt under the skin around the knee. In the posterior part of the patella there are two articular surfaces – lateral and medial, and they connect with the lower condyles of the femur. This creates the patellofemoral joint, which is one of the elements of the knee joint.

The upper part of the patella is connected to the tendon of the quadriceps muscle of the thigh. The lower part of the kneecap has a so-called the tip to which the patella ligament attaches. The patellar ligament, in turn, connects to the tibia, more precisely to a small protrusion in its upper part, called tibial tuberosity.

On both sides of the kneecap, there are additional fibrous structures, i.e. the patella straps, which connect to the tibia. Together with the tendon of the quadriceps muscle and the patellar ligament, they contribute to its stabilization. This allows the kneecap to move in a specific plane and is secured against excessive displacement. The membranes that form the joint capsule attach to the kneecap articular surfaces. The synovial membrane of the joint capsule creates numerous protrusions, called synovial bursae. There are supra-, sub- and pre-patellar bursae in the area of ​​the kneecap. Inside the synovial bursae, the production of synovial fluid, i.e. a substance filling the joint and reducing friction within it, takes place.

On the posterior-lower side of the patella there is the so-called the infatellar fat body (Hoffy’s fat body), thanks to which it is possible to absorb shocks and fill the gaps in the knee joint. The patella consists mainly of bone tissue, which appears in the kneecap around the age of four, and the process of ossification of the patella takes several years (on average, 3-6 years of age). Previously, the main component of the kneecap is cartilage, which never completely disappears. Cartilage tissue, thanks to its flexibility, enables the transfer of high joint loads.

Thanks to a small hole in the patella, blood (and thus oxygen and nutrients) enters the bone. Cartilage, on the other hand, is nourished with synovial fluid, and if damaged, it is usually impossible to fully repair it.

See also: Knee to be replaced?

Patella – functions

The main function of the kneecap is to protect the knee joint from injuries. As it is the most forward part of the joint, it absorbs a lot of energy in the event of an injury, which in turn makes the kneecap more susceptible to damage.

The kneecap, however, not only covers the other structures of the knee, but also absorbs and disperses the stresses on the femur, especially during movement such as running or jumping.

Of course, this is not the end of the role played by the kneecap in the movement apparatus. It is connected with the quadriceps muscle of the thigh, forming a common part, i.e. the patellar ligament. In this case, the function of the kneecap is to transfer the strength of the muscles, and more precisely its task is to extend the knee joint. When the quadriceps contract, the patella rises upwards, which increases the angle of impact on the tibia. As a result, the knee extends with less effort.

Patella – diseases

Patellar diseases – dislocation of the kneecap

Our kneecap can be pushed out of its place or dislocated when we put our foot down and suddenly change direction. It can also happen when something hits your leg and moves it in a different direction.

Signs of a patellar dislocation include:

1. the connection looks out of place, although it may roll back by itself;
2. sound or sensation of the kneecap popping out;
3. severe pain;
4. the inability to straighten the leg and the inability to walk;
5. sudden swelling.

Patellar diseases – instability and dislocation of the patella

Our knee can also dislocate without injury as there is a problem with the structure of the patella. This is called patella instability. It is most common in children and adolescents, although it can also happen in adults. Structural issues may include:

1. The kneecap sits in a cut at the end of the femur called a trochlear groove. If this cutout is very shallow or uneven, the kneecap slips out of place more easily.
2. Our ligaments are looser, making the joints more flexible and prone to sprains. This is especially true of girls.
3. Cerebral palsy and Down syndrome can cause muscle weakness and balance problems that affect the kneecaps.
4. Some babies are born with unstable kneecaps.

Whatever the cause, the symptoms of a patella dislocation are the same.

Usually, in the event of such an injury, the patient is fitted with a brace to prevent the patient from moving the knee. Within 1-2 weeks, you will begin physical therapy to strengthen your thigh muscles. It is expected to take approximately 1 to 3 months to recover.

If the kneecap fully pops out, the doctor will first gently push it back into place. In some cases, you may also need surgery to repair damage to the femur or the cartilage behind the knee.

If the injury recurs, surgery will likely be needed to tighten the ligaments and help keep the kneecap in place.

See also: Do you train Here are the five most common injuries that can happen to you when you play sports

Patellar Diseases – Patella Subluxation

This happens when the kneecap shifts slightly but does not completely dislocate. It’s also a kind of kneecap instability.

Symptoms of a patellar subluxation include:

1. pain in the front of the knee;
2. feeling of loose kneecap;
3. our knee suddenly gives way.

Patellar diseases – fracture of the kneecap

This is a serious injury in which we break the kneecap, usually due to:

1. fall, landing directly on the knee;
2. a direct impact to the knee, such as a knee impact to a dashboard in a car accident.

If we break the kneecap, symptoms may include:

1. bruises;
2. not able to walk;
3. not being able to straighten your knee or keep it straight as you raise your leg.

If the broken pieces of the patella are still lined up, your doctor will use an immobilizer to keep everything in place during treatment. Sometimes the injured person may still put stress on the knee. In other cases, it may not be able to walk for 6 to 8 weeks.

For a more severe fracture, surgery is usually required. Your doctor may use screws, pins, or wires to keep pieces of bone in place. In both cases, you will need physical therapy to deal with stiffness, regain range of motion, and rebuild leg strength.

See also: Diet after bone fractures

Patellar diseases – rupture of the patella ligament

The patella ligament begins in the thigh muscles, wraps the kneecap, and connects to the top of the tibia. If we break the tendon completely above the kneecap (quadriceps tendon) or below (patellar tendon), we will not be able to straighten the knee.

1. A little breakup. For small breaks, a splint is usually worn and orthopedic crutches are used for 3 to 6 weeks. The brace keeps the knee straight while the tendon heals. We also need the help of a physical therapist to help us increase leg strength and range of motion.
2. Big breakup. Most people need surgery because the patella tendon is severely torn. It usually takes 6 to 8 weeks for a tendon to heal after surgery, but it can take up to a year to fully heal.

Patellar diseases – patellar tendinitis

Also called patellar tendinopathy or jumper’s knee, it is an injury to the patellar tendon. It is common among people who play sports such as basketball and volleyball.

Treatment usually begins with basic self-care such as rest and over-the-counter pain medications.

However, you may need to contact a physical therapist who may:

1. reduce pain and swelling with ice massage, ultrasound or iontophoresis, which use a small amount of electricity to force cortisone, a medicine, into the body through the skin;
2. show us exercises for stretching and strengthening the thigh muscles;
3. show you how to use a knee clamp to relieve pressure on the tendon.

If these treatments don’t work, your doctor may talk to us about a cortisone injection to relieve pain and swelling. The downside to this treatment is that it can also weaken the tendon and increase the likelihood of a rupture. Another option is the injection of platelet-rich plasma. However, it has not been proven whether this method works better than physiotherapy or other treatments.

This happens very rarely, but if nothing else works, you may need surgery to remove damaged tissue and repair the tendon.

See also: Brain injuries caused by playing basketball are increasing

Patellar diseases – patellofemoral pain syndrome

This general term describes pain in the front of the knee and around the kneecap. This is sometimes referred to as “cinema lover’s knee.” Patellofemoral pain syndrome, usually caused by overtraining, can lead to pain, stiffness, or a feeling of buckling in the knee and lower femur. It is common in athletes, especially women and young adults.

If we have patellofemoral pain syndrome, we may feel pain when:

1. we go up or down stairs;
2. we kneel or crouch;
3. we sit with our knees bent for a long time, for example, during a movie or a plane flight;

We may also hear our knees slam as we climb stairs or get up after sitting for a long time.

Patellofemoral pain syndrome can occur due to strain on the knees such as going up (too many steps). The pain may start because we suddenly started exercising more, for example going from training 3 days a week to 6. It could also be because we made our training more intense.

Other things that can trigger patellofemoral pain syndrome:

1. poor exercise technique;
2. wrong equipment such as shoes;
3. changing the exercise surface; for example, running on a bad surface.

Often the condition improves with over-the-counter painkillers and the “RICE” method:

1. R – Rest. Avoid activities that cause pain and try not to put stress on your knee;
2. I – Ice. Wrap an ice bag in a towel and apply it 20 minutes at a time, several times a day;
3. C – Compression. Use a stretchy bandage with a kneecap opening. You want it to be tight but not tight;
4. E – Elevation. Keep your knee higher than your heart as much as possible.

Our doctor may also suggest physical therapy to:

1. improve strength and range of motion of the thigh, hips, abdomen and lower back;
2. show you how to tighten your knee or use an orthosis to reduce pain;
3. teach us how to improve technique if the knee moves while squatting.

On rare occasions, surgery may be needed to remove damaged cartilage, loosen the tendons, or realign the patellar tendon and the top of the tibia.

Patellar disease – a disorder involving a misplaced patella (in the knee)

Patellofemoral pain syndrome can also result from a problem with the alignment of the knee. When we have a misalignment or a problem with a misplaced kneecap, the kneecap can move to one side of the block groove when we bend the knee. This irritates the area, causing pain. These disturbances can be due to general alignment problems between the leg and hip. Weak thigh muscles may also be part of the problem.

See also: Exercises for the inside of the thighs

Patellar diseases – chondromalacia of the kneecap

Damage to the cartilage behind the kneecap is called chondromalacia. You can then feel a dull pain in the area or under the kneecap, which worsens when you go down the stairs.

Treatment starts again with taking care of yourself:

1. avoiding activities that cause pain;
2. applying a towel-wrapped ice bag for 15 to 20 minutes, four times a day for several days;
3. taking over-the-counter painkillers.

You can also visit a physical therapist for help with:

1. changing the way of performing the exercises – strenuous exercises as well as kneeling and squatting should be avoided;
2. choosing the best footwear for your activities;
3. a safe exercise to stretch and strengthen the thighs and hamstrings;
4. choosing shoe insoles, if we need them;
5. choosing a tape or an orthopedic appliance to keep the kneecap in line.

If these procedures do not bring the desired results, surgery may be required to remove the damaged cartilage and correct the patella.

Patellar diseases – prepatellar bursitis

The Bursa is a small, fluid-filled bag. It eases friction between bones and soft tissue such as tendons. In prepatellar bursitis, the bursa on the front of the knee becomes irritated and swells with extra fluid. This puts pressure on the knee, which leads to pain.

If it happens because of an injury, it usually clears up on its own with a little self-care, including:

1. avoiding activities that cause pain;
2. wrap the ice in a towel and apply it for 20 minutes three to four times a day;
3. keeping your knee over your heart as much as possible;
4. taking over-the-counter pain medications.

If these treatments don’t work, your doctor may:

1. draw the fluid out of the bursa with a needle;
2. use a cortisone injection to relieve pain and swelling.

If the bursa is infected, you will also need to use antibiotics. If they don’t work, you may need surgery to remove the extra fluid.

If we have recurring problems with the bursa, the doctor may suggest surgery to remove it.

Patella – research

The kneecap is subjected to various tests that allow to assess the locomotor system and the nervous system of the patient. Such studies include, for example:

1. test of the knee reflex – involving hitting the patella ligament with a hammer, where the correct reflex is a gentle extension of the knee. If the reflex is too strong or too weak, abnormalities in the nervous system can be detected.
2. kneecap baling – performed during an orthopedic examination. A positive result indicates there is too much fluid in the knee joint, usually blood or inflammatory exudate.

Patella – prophylaxis

Every possible kneecap injury cannot be avoided. However, there are a few simple steps you can take to keep your knees healthy:

1. maintain a healthy weight. Since extra weight can increase our chances of developing osteoarthritis, you should maintain a weight appropriate for your height and age to reduce the strain on your knees and avoid increased chances of knee injuries.
2. wear properly fitted shoes. This will help to maintain the correct positioning and balance of the legs, and ultimately prevent knee injuries.
3. warm up. Before starting any exercise, be sure to warm up well, and then do some stretching exercises. If we stretch the muscles in the front and back of the thighs, it will reduce the tension in the tendons, ultimately reducing the pressure on the knees.
4. do little strenuous exercise. In the gym, it’s better to choose a rowing machine or a home treadmill with integrated Nordic walking poles. Both provide powerful training with little pressure on the knees.
5. swim or walk. It’s best to opt for swimming or walking when you are active outside the gym.
6. exercise strength. It’s a good idea to strengthen your leg muscles to better support your knees and avoid injuries by exercising with weights. First, however, it is recommended that you consult an expert on choosing the right weights to prevent knee pain.
7. do not reduce your activity. A decline in activity leads to weakness, increasing the risk of injury.
8. do not suddenly change the intensity of your exercise. It is recommended that you increase the intensity of your exercise gradually to avoid knee pain.
9. consider physical therapy. If you already have a knee injury, visit a physical therapist who can help you determine the appropriate exercise regimen.

We can see that some people with knee problems wrap their knees during exercise or at other times. People generally do this because they feel good about it. While it won’t hurt your knees, it won’t help you avoid injury. If we are wrapping our knees, remember not to wrap them too tightly as this can also cause knee problems.

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