Running is a popular sport that is easy to incorporate into your daily routine. However, if you don't run properly, it can put strain on your knees, and many people suffer from a condition known as "runner's knee."
Although it is called "runner's knee," there are several diseases that can cause knee pain due to running. Among them, one that deserves special attention is "chondromalacia patella."
This article will explain in detail the various symptoms of runner's knee, focusing on chondromalacia patellar syndrome. We will provide useful information for all runners, including causes, treatments, and prevention, so be sure to check it out
table of contents
What is chondromalacia patella?
Chondromalacia patella is a condition in which the patellar cartilage behind the kneecap becomes soft and degenerates
Although it is on the back side, it is sandwiched between the femur and the patella, so it is actually located on the front of the knee
Symptoms
The main symptoms are pain, swelling, and discomfort in the knee
pain
Pain is particularly likely to occur around and directly below the kneecap. At first, the pain is felt only during or after exercise, but as the condition progresses, pain can also be felt in everyday life
Additionally, when bending and straightening your knee, you may feel a rough or slight catching sensation inside the knee. This is caused by the unevenness of the softened cartilage surface
In everyday life, deep squatting can cause pain in the front of the knee. Additionally, standing up from a squatting position puts the most pressure on the cartilage, so this is when pain is most likely to occur
Going down stairs can also put strain on the cartilage, causing sharp pain in the front of the knee. Standing up after sitting for a while can also cause knee pain. It's important to understand that prolonged sitting temporarily reduces the lubrication of the cartilage, meaning the protective synovial fluid doesn't reach the cartilage properly
Swelling (joint edema)
There may be slight swelling around the kneecap. This swelling is not due to inflammation and redness, but rather to an increase in the production of synovial fluid (joint fluid) caused by cartilage damage, so it would be more accurate to say that "water accumulates."
As the joint effusion progresses, the discomfort may increase, and the increased pressure within the joint may cause pain throughout the knee
Causes of chondromalacia patella
It is said that when running, the knee is subjected to a force two to three times greater than the body's weight. This repeated stress every time the knee lands causes damage to the cartilage behind the patella
However, simply running regularly does not necessarily increase your risk of developing chondromalacia patellar. It is important to note that the following factors increase your risk of developing the condition:
A sudden increase in training volume
A sudden increase in training volume also increases the risk of developing chondromalacia patellaritis. For example, if someone who was previously only running 5km once a week suddenly increases their training to 10km three times a week, excessive strain is placed on the cartilage behind the patella, causing it to soften and degenerate
Cartilage has the ability to adapt to moderate loads. There is no problem with gradually increasing the load. If you increase the load over time, cartilage will gradually become stronger and be able to withstand greater loads
Anatomical problems
People with a large Q angle (the angle between the quadriceps and patellar tendon) tend to have their patella pulled outward, which can put uneven strain on the cartilage
The type of arch in your foot also affects your risk of developing the condition. If you have flat feet, excessive pressure is placed on the inside of your foot when running, which can adversely affect the alignment of your knee and result in uneven pressure on the patellar cartilage
Many of these anatomical factors are congenital, but they can sometimes be improved by choosing the right shoes and, in some cases, using insoles
Muscle balance issues
To maintain healthy knees, it is better to create a balanced plan that strengthens weak muscles rather than further strengthening already strong muscles
In particular, in the case of chondromalacia patellar syndrome, the balance between the quadriceps (muscles on the front of the thigh) and gluteus (muscles in the buttocks) is important
For example, if your quads are too strong and your glutes are weak, your knees will move too far forward when you run, putting too much pressure on your patella (kneecap), which can contribute to cartilage softening and degeneration
Weakness of the vastus medialis, a part of the quadriceps, can also cause chondromalacia patella. A weak vastus medialis can prevent the patella from moving flexibly, which can lead to uneven pressure on the cartilage
Core strength is also important. A weak core can make it easier to lose balance while running, which can put extra strain on your knees and increase stress on your patellar cartilage
Runner's knee in the broad sense
As mentioned above, "runner's knee" itself does not refer to a specific disease. It is a general term for several knee conditions that are caused or worsened by running. In addition to chondromalacia patellar syndrome, the conditions that are referred to as runner's knee include the following:
Iliotibial band syndrome
This condition is most commonly known as "runner's knee." It often causes pain on the outside of the knee
Patellofemoral pain syndrome
It is characterized by pain around the kneecap and is sometimes treated as a type of runner's knee
Patellar tendonitis
Also known as jumper's knee, it is often seen in runners. Because the patellar tendon is attached under the kneecap, pain often occurs on the lower part of the knee
Anserine bursitis
It is a condition that causes pain on the inside of the knee and is sometimes referred to as a type of runner's knee
Meniscus injury
It can be aggravated by running and is sometimes treated as a type of runner's knee
Each has different characteristics, but all can be caused or aggravated by running
Diagnosis of Chondromalacia Patella
Evaluation is performed using various imaging diagnostics. MRI examinations can non-invasively evaluate the state of cartilage. Softening is determined by changes in cartilage thickness and signal intensity. Ultrasound examinations can evaluate cartilage thickness and surface irregularities
In addition, arthroscopy may be used to directly examine the cartilage and assess the extent of damage using a grade of 0 to 4 called the Outerbridge classification
Treatment for chondromalacia patella
In the early to mid-stages of chondromalacia patellar disease, this conservative treatment is likely the first choice
Rest your knees
During the acute phase, rest your knee for 2-3 days and avoid any movements that cause pain. Complete rest is not necessary, and moving around in your daily life is usually not a problem
Once the pain has subsided, you can gradually increase your activity, but refrain from strenuous exercise that causes pain. This generally takes about 2 to 4 weeks, but this varies depending on the severity of the symptoms
rehabilitation
Rehabilitation is performed with the aim of reducing the strain on the cartilage. In the case of chondromalacia patella, a combination of stretching and muscle training will be used to effectively strengthen the muscles
Stretching the quadriceps increases flexibility around the kneecap
Strengthening the vastus medialis also helps support proper patellar movement, while gluteal muscle training reduces strain on the knee and improves overall lower limb balance. Core muscle strengthening is also important
In most cases, symptoms will have already appeared by the time you begin rehabilitation, so be sure to train under the supervision of a professional to avoid doing things your own way and worsening the pain
drug therapy
Painkillers and hyaluronic acid injections may be administered to reduce inflammation and pain
surgery
Most cases of chondromalacia of the patella improve with conservative treatment, but if symptoms are severe or conservative treatment is not effective enough, surgical treatment may be considered
Arthroscopic surgery
This is the most common surgical method. An endoscope is inserted through a small incision to treat the damaged cartilage. Specifically, the damaged cartilage is removed, the cartilage surface is smoothed, and small holes are drilled into the bone beneath the cartilage to encourage the formation of new cartilage-like tissue
regenerative medicine
This is the latest medical treatment that is attracting attention as a treatment that can regenerate cartilage even when surgery is not an option
Autologous chondrocyte transplantation
This method involves extracting cells from the patient's own healthy cartilage, culturing and expanding the cells, and then transplanting the expanded cells into the damaged area
stem cell therapy
This treatment utilizes stem cells extracted from bone marrow or adipose tissue, which are then stimulated to differentiate into chondrocytes. When injected or transplanted into the damaged area, these cells are able to form new cartilage tissue, which is why it is attracting attention
Platelet-rich plasma (PRP) therapy
This method extracts concentrated platelets from the patient's own blood, and injects PRP, which is rich in growth factors, into the damaged area, slowing the rate of cartilage degradation and promoting repair
Other measures
You also need to pay attention to your lifestyle and running, which can put strain on your knees
weight control
Excess weight puts more strain on your knees, so maintain a healthy weight by eating a healthy diet and exercising regularly
hydration
Proper hydration is also important for lubricating joints, so be sure to drink plenty of water
Choosing the right shoes
Running shoes play an important role in absorbing shock to the knees. Choose shoes that fit the width and arch height of your foot. Adequate cushioning is also necessary to absorb shock. Also, even if your shoes fit well, it is not a good idea to continue wearing the same shoes forever. This will result in a decrease in cushioning and support function. If the grooves on the soles become shallower, this is also a sign that your shoes need to be replaced, so be sure to change them regularly
summary
By practicing preventative measures on a daily basis, you can significantly reduce your risk of developing chondromalacia patellar. However, the best method will vary depending on your individual constitution and situation. If the pain persists or you have any concerns, be sure to consult a specialist