Axial photography of patella

If your knee hurts when you go upstairs and downstairs, or if you press the round bone in front of your knee and feel a rustling sound inside your joints, you should consider whether there is a "patella softening" problem.

Patella softening is a popular term. Many people tend to think that the whole patella has become soft. Patella softening actually refers to chondromalacia of patella.

0 1, patella structure

First of all, let's learn about the general structure of the knee joint. Distal femur, proximal tibia and patella are the main bone tissues of knee joint. Among them, femur and tibia form articular surface, and femur and patella form articular surface (patellofemoral joint). Under normal circumstances, when the knee joint is bent, the patella moves up and down in the groove of the femur (femoral trochlea).

The so-called patellar cartilage refers to the side where the patella contacts the femur. The surface is very smooth and consists of a layer of cartilage.

If the knee joint cavity is compared to a room, then the patellar cartilage is similar to the wall skin of our room. Patella softening, on the other hand, is like a room soaked in water, with soft walls, peeling and cracking. The femoral cartilaginous surface corresponding to the patella will also wear accordingly.

(The white part in the picture is patella cartilage, and the yellow part is cartilage exfoliation area. )

02. Causes of chondromalacia patellae

1. congenital factors

Some people's patella position is abnormal, the patella is not in the "groove" of the femur, the position is offset, or the size of the patella does not match the development of the "groove" of the femur, resulting in "out-of-groove" friction, resulting in patella cartilage wear.

2. Acquired factors

(1) Degeneration of knee joint or excessive flexion of knee joint.

From this picture, we can clearly see that when our knees are straight, the cartilage surfaces of patella and femur are separated, so it is not easy to produce friction. However, when we bend the knee joint, the pressure on the articular surface of the patella facing the femur is very great. This long-term friction will lead to articular cartilage wear, causing chondromalacia patellae.

Then let's think about it. In daily life, what actions should we often bend our knees? For example:

climb mountains

climb the stairs

There is a data for everyone: when we go up the steps, the force borne by the patella when the knee joint bends is 3.3-4 times the weight! That is to say, if your weight is 100 kg, then the force on the patella at the moment you step on it is 330-340 kg! Therefore, climbing stairs and mountains is definitely a kind of destruction and torture to the knee joint.

Patients with chondromalacia patellae should especially avoid these activities!

(2) Old trauma: For example, we sprained and scraped the knee joint before, which caused the ligament (tendon) around the joint to tear. Without nursing and regular treatment, the position of patella is easy to change and the joints are worn out during ligament reduction.

(3) The strength of quadriceps femoris is insufficient: the muscles around the knee joint (especially the muscles on the front thigh, quadriceps femoris) are important structures to maintain the stability of the knee joint. In patients with chondromalacia patellae, the quadriceps femoris will obviously atrophy due to pain and decreased activity. This will reduce the stability of the knee joint, shift the position of the patella and aggravate patella softening.

03. Symptoms of chondromalacia patellae

Pain: it's mild. It hurts only when you go upstairs and downstairs. It may be that your knee suddenly becomes soft and weak. Sometimes it hurts when squatting, such as squatting to the station, especially when lifting heavy objects. Serious daily activities will hurt, and there is a phenomenon that the knee joint hits the soft leg when walking. In addition, if you massage the edge of the patella by hand, there will often be obvious tenderness.

Ring: When the knee joint is flexed and stretched, there is often a sound under the patella. In severe cases, if you sit and straighten your legs, put your hand on the patella and rub it on the patella, you will hear a "rustling" sound, just like there is sand in your joints.

Swelling: Because there is inflammation inside the joint, the synovium of the joint secretes a lot of fluid, so it shows swelling of the knee joint.

Thin: patella softening, will lead to muscle atrophy, quadriceps weakness, so the thigh appearance will become thin.

04. Diagnosis of chondromalacia patellae

1, self-diagnosis action

(1) patella grinding test: press the patella by hand and slide it up and down or left and right, if there is pain, rough friction and noise; Or push the patella aside with your hand and press the cartilage surface at the edge of the patella with the fingers of the other hand. If there is pain, there may be chondromalacia patellae.

(2) One-leg squat test: If you doubt your patella softening, you can try to stand on one leg and then squat slowly. If you feel pain, your legs are weak, and you can't stand on one leg after squatting, it means that you may have chondromalacia patellae.

2. Imaging diagnosis

Here, we recommend that if patients with chondromalacia patellae are suspected, they can take 30, 60 and 90 axial photos of the patella to see if the position of the patella has changed.

05. Treatment of chondromalacia patellae

1, oral drugs:

There are two main types.

One is non-steroidal anti-inflammatory drugs. It has anti-inflammatory and analgesic effects, and is suitable for acute stage of patella softening.

The second category is cartilage nutrition: mainly refers to amino sugar cartilage nutrition.

2, physical therapy:

Ultrashort wave: anti-inflammatory effect is achieved through high-frequency electromagnetic field.

Medium and low frequency electrotherapy: improve circulation by improving the permeability of cell membrane.

Wax therapy: promote local fever and blood circulation.

Of course, the specific treatment methods and doses need to be arranged by professional physiotherapists. Physical therapy instruments at home will also have a certain effect, but the effect is relatively poor.

3, protective gear processing:

There are many knee patella fixation protectors, which can effectively correct patella dislocation and subluxation, correct patella outward displacement and keep patella stable. After some patients wear it, the knee pain will disappear when going up and down the stairs, which is quite useful.

4. Functional exercise

As we said just now, the decline of quadriceps femoris muscle strength is closely related to patella softening, so strengthening quadriceps femoris muscle strength and restoring the stability of knee joint is the core of treating chondromalacia patellae. Today, I recommend two rehabilitation exercises:

Leg lifting exercise

Lie on your back, lie flat on the bed. Straighten your legs with the greatest strength, and then lift them to a height of about 15 cm from the bed surface. Be sure to straighten your knees. After practicing for a period of time, you can improve your strength and change to sitting exercise. Just sit on the bed, sit up straight, and then lift your legs. Because the hip joint flexes after sitting up, the iliopsoas muscle relaxes and does not participate in contraction, which does not help the quadriceps, so it is more tired. It is better to practice the muscles on the front side of the thigh.

Static squat exercise

Feet shoulder width apart, toes and knees forward, upper body leaning against the wall, center of gravity resting on heel. The knee joint should not exceed the toe in the vertical direction, and the flexion angle of the knee joint should not be greater than 90 degrees. Hold the posture until you are exhausted, rest for 10 second, and then repeat 10 times/group, 2-3 groups/day. Simply put, it is to practice "Zama Bu" with your back against the wall! .

Of course, these exercises should be gradual, from less to more, from easy to difficult, from static exercises in static posture to dynamic exercises in sports, from simple movements to complex movements. These are just the simplest and safest basic exercises. Because too much excessive practice can not only relieve symptoms, but even aggravate cartilage damage. Therefore, without special guidance, it is better not to practice blindly by yourself.

In addition, it is more important to adjust the activities of daily life. You can't stay where you are because you are afraid of pain, and you can't feel that it is better to practice than not to practice. You can practice hard with your teeth Because insufficient exercise and excessive exercise will be counterproductive and will aggravate the condition!

5, surgical treatment:

If conservative treatment is ineffective for a period of time, arthroscopic minimally invasive surgery can be considered. Arthroscopic surgical treatment is mainly 1, cleaning the damaged articular cartilage. 2. Restore the balance of medial and lateral retinaculum of knee joint, especially the release of lateral retinaculum.