OVERVIEW

What is patellar chondromalacia?

Patellar chondromalacia is a degenerative change (commonly known as aging) that occurs in the cartilage surface of the patella in the knee joint. In the early stages, there are no obvious symptoms, though a clicking sound may sometimes be heard when moving the knee. As it progresses, symptoms like knee pain and limited mobility may develop, and in severe cases, it can lead to osteoarthritis.

The exact cause of this condition is unclear, but it is generally associated with aging or improper physical activity. Therefore, early diagnosis and appropriate preventive measures are crucial to prevent its onset or progression.

Is it normal for the patella to age with time?

Just as we age, patellar aging is a completely normal process.

• Ages 15–30: The knee joint is in a "perfect state," but the patellar cartilage, which cushions impact, is only 3–5 mm thick. Since it lacks nerve endings, pain is either absent or resolves naturally within 1–2 days. Thus, for a long period between 15–30 years, there are no "warning signs."

• Ages 30–40: Mild wear occurs, making this a fragile period. Short-term knee soreness may appear but often goes unnoticed.

• Ages 40–50: Knee soreness frequently occurs after long walks, indicating it’s time to start joint care.

• Age 50+: Knee pain becomes frequent and noticeable, with cartilage nearly worn through. Arthritis begins to develop, signaling that the patellar cartilage’s "lifespan" is nearing its end.

This shows that degeneration of knee joint cartilage begins after age 30. The prevalence of osteoarthritis is only 2% in those under 45, but rises sharply to 68% in those over 65. Natural wear progresses slowly, while abnormal wear leads to disease, so knee joint care should start early.

Which department should I visit for patellar chondromalacia?

Typically, orthopedics or joint orthopedics.

SYMPTOMS

What are the symptoms of chondromalacia patellae? Is chondromalacia patellae related to knee pain?

In the early stages of chondromalacia patellae, there are no particularly obvious symptoms, but a clicking sound behind the patella may occur during knee flexion and extension. As the condition progresses, pain behind the knee during flexion and extension may develop, especially when squatting, climbing stairs, or hiking.

Of course, for young people with knee pain, other common conditions such as meniscus tears, cruciate ligament injuries, collateral ligament injuries, or synovitis should also be considered.

For older adults, the possibility of osteoarthritis or loose bodies in the knee joint should also be taken into account. Therefore, if knee pain occurs without obvious trauma or other triggers, it is best to seek medical attention promptly to determine the cause and receive targeted treatment.

CAUSES

Who is prone to patellofemoral chondromalacia?

It commonly occurs in middle-aged individuals, though clinical observations show a trend toward younger onset ages. This is likely due to increasing public enthusiasm for fitness and exercise, coupled with improper selection of exercise types and poor control of workout intensity.

High-impact activities like mountain climbing cause severe wear on the knee joint, particularly the patellofemoral joint. Persistent improper exercise may lead to degenerative changes in the articular cartilage of the patellofemoral joint, resulting in patellofemoral chondromalacia.

DIAGNOSIS

How is patellar chondromalacia diagnosed? What tests are needed?

Patellar chondromalacia can generally be diagnosed through clinical physical examination. Conventional X-rays of the knee are of little significance (articular cartilage cannot be visualized). Even MRI, which is sensitive to cartilage, has limited diagnostic value for early-stage cases. However, for cases with obvious cartilage damage, it can provide clear imaging.

Clinically, doctors perform these tests mainly to rule out other conditions, such as meniscus injuries or osteoarthritis.

How to determine muscle atrophy in patellar chondromalacia?

Examiners assess muscle atrophy by measuring thigh circumference.

The specific method is: The patient lies supine with lower limb muscles relaxed. First, locate the midpoint of the patella as a reference, then use a soft tape measure to measure the thigh circumference at 5 cm, 10 cm, and 15 cm above the patella.

After bilateral measurements, compare the results. A difference of more than 1 cm between the affected and healthy sides indicates muscle atrophy on the affected side.

TREATMENT

How is patellar chondromalacia generally treated? Is medication necessary?

The treatment of patellar chondromalacia is primarily conservative, with specific measures including:

• Avoid strenuous activities and reduce exercise intensity appropriately.

• Avoid activities that require repeated knee flexion and extension, such as hiking, frequent stair climbing, cycling on steep slopes, or performing excessive squats in a short time, especially while carrying heavy objects.

• If pain is significant, oral or topical nonsteroidal anti-inflammatory drugs (NSAIDs), such as Celebrex, Difene, Loxonin, or Voltaren, can be used to relieve symptoms.

• Additionally, strengthening the muscles around the knee joint through daily exercises can be very helpful.

If conservative treatment is ineffective, arthroscopic examination and treatment may be necessary.

Can patellar chondromalacia be cured?

Patellar chondromalacia is a degenerative condition that worsens with age and cannot be completely cured. However, comprehensive treatments such as medication and strengthening knee muscles can significantly improve symptoms and slow disease progression.

If symptoms do not improve after about 3 months of conservative treatment, a knee MRI may be needed to assess the condition of the patellofemoral joint cartilage. In some cases, minimally invasive arthroscopic surgery may be required.

Knee arthroscopy not only allows for a detailed evaluation of cartilage damage but also enables the surgeon to repair and clean the damaged cartilage under direct visualization. While this can help relieve symptoms, the extent of improvement varies depending on the severity of the damage and individual factors.

What exercises can help alleviate pain for patients with patellar chondromalacia?

Stretching and muscle relaxation exercises can help improve pain.

Stretching exercises: Here are some stretching exercises suitable for home practice:

1. Quadriceps stretch

2. Hamstring stretch

3. Iliotibial band stretch

Muscle relaxation exercises: A foam roller is a rehabilitation tool for muscle relaxation. By applying body weight to the foam roller and slowly rolling, pressure is exerted on the muscles, achieving a massage-like relaxation effect.

Patients can choose a smooth, soft foam roller for home muscle relaxation exercises:

1. Quadriceps foam rolling

2. Hamstring foam rolling

3. Iliotibial band foam rolling

What should patients with patellar chondromalacia do if their legs feel weak?

Patients often experience weakness or instability in the knees, especially when descending stairs, due to quadriceps atrophy and impaired proprioception.

To improve knee stability and resist external disturbances, rehabilitation exercises can help:

1. Strengthen thigh and hip muscles.

2. Knee proprioception training. Here are some self-administered proprioception exercises. Unstable surfaces can be created using professional rehabilitation tools like balance pads or household items such as soft cushions or pillows (taping is recommended during training):

   • Single-leg standing

   • Single-leg standing on an unstable surface

How can patients with patellar chondromalacia strengthen their hip muscles?

The hip muscles mainly include the gluteus maximus, gluteus medius, and gluteus minimus. The gluteus maximus acts as the "engine" of the lower limbs, while the gluteus medius serves as the "stabilizer," improving femoral internal rotation and balancing knee joint forces. Hip abduction and external rotation strength training, especially eccentric external rotation training, combined with quadriceps exercises, can lead to more lasting functional improvements. Here are some home-based hip-strengthening exercises using resistance bands:

1. Glute bridge

2. Clamshell

3. Monster walk

DIET & LIFESTYLE

What should patients with chondromalacia patellae pay attention to in daily life?

• For patients with chondromalacia patellae, there are no specific dietary restrictions. In terms of clothing, it is important to keep the knees warm to prevent cold stimulation from aggravating knee pain.

• For those with severe symptoms, in addition to taking oral or topical medications, physical therapies such as heat compresses can help alleviate symptoms.

• Patients with chondromalacia patellae can engage in exercises like swimming or flat-road cycling, but they must avoid excessive activity. Additionally, exercises to strengthen the muscles around the knee joint are recommended.

What dietary precautions should patients with chondromalacia patellae take?

There are no specific dietary taboos; a balanced diet is sufficient.

• When cooking, use less salt, oil, and high-salt seasonings, and avoid pickled vegetables or meats.

• Do not rely solely on refined grains; replace some staple foods with whole grains, legumes, potatoes, or pumpkins.

• Balance meat and vegetable intake. Prioritize white meats like chicken, duck, or fish, and limit fatty meats. Eggs and milk are important sources of protein and other nutrients.

• Vegetarians can consume more beans and soy products to supplement protein.

• Eat plenty of fresh fruits and vegetables.

• Quit smoking and alcohol.

What exercises can strengthen the muscles around the knee for patients with chondromalacia patellae?

Recommended exercises:

• Straight leg raise: Lie flat on your back, straighten the affected leg, flex the toes upward, and lift the leg to about 30 degrees from the bed. Hold for 20 seconds while keeping the toes flexed, then slowly lower. Repeat 20 times per set, 10 sets daily.

• Wall squat: Stand with your back against a wall, feet shoulder-width apart, and lower into a squat until thighs are slightly less than 90 degrees to the calves. Hold for 20 seconds, then relax. Repeat 20 times per set, 10 sets daily.

What can patients with chondromalacia patellae do during knee pain episodes?

Patients often experience knee pain after long-distance running, hiking, or intense jumping exercises. During this phase, the following methods can help relieve pain:

1. Avoid strenuous activities like prolonged running, deep squats, stair climbing, or jumping.

2. For severe pain, take nonsteroidal anti-inflammatory drugs (e.g., ibuprofen) under a doctor’s guidance (non-addictive).

3. Apply ice to the affected area: Wrap an ice pack in a thin cloth, place it on the knee, and secure it with an elastic bandage for 15–20 minutes.

4. Perform pain-free rehabilitation exercises (e.g., supine leg raises, clamshells, glute bridges, adductor training). If pain occurs, wait until the acute phase subsides.

How can patients with chondromalacia patellae return to running?

Chondromalacia patellae does not mean a permanent ban on running, but the following precautions apply:

1. Resume running only after the acute phase (significant pain/swelling) ends—never run through pain.

2. Strengthen glutes and quadriceps through rehabilitation to improve knee stability—muscles protect joints.

3. Wear proper running shoes (cushioned or stability-based). Use orthotic insoles if you have flat feet or high arches.

4. Warm up before running with dynamic stretches and muscle activation (e.g., crab walks, squats, lunges) to prepare muscles.

5. Follow a gradual running plan—key to returning safely.

Gradual running plan: Progress from walking to running. Start with treadmill walking, transition to brisk walking, then slow jogging. Begin with 15-minute jogs every other day, increasing by 5 minutes weekly. Once comfortable jogging pain-free for 40 minutes, increase distance by 10% weekly. If pain/swelling occurs, reduce intensity and progress more slowly.

What should patients do if knee pain occurs during exercise?

Rehabilitation should follow the pain-free principle. Training through pain hinders muscle growth, while complete inactivity leads to muscle atrophy, joint stiffness, and reduced cardiovascular fitness—creating a vicious cycle.

Patients should self-check these two aspects to adjust training:

1. Squat form: Improper squats (e.g., excessive knee dominance, inward knee collapse, or misaligned posture) can cause pain. Learn correct techniques under a therapist’s guidance.

2. Intensity: Progress gradually. If swelling or pain worsens the next day, reduce intensity.

PREVENTION

How to Prevent Patellar Chondromalacia?

To prevent patellar chondromalacia, consider the following recommendations:

• Avoid Intense Exercise: Avoid unscientific repetitive squatting and strenuous activities such as mountain climbing, stair climbing, or other exercises that place excessive load on the knee in a flexed position. Sudden increases in exercise intensity should also be avoided. Understand how to prevent improper knee loading: When lying down, the knee bears almost no weight. Standing and walking impose a load of about 1–2 times the upper body weight. Going uphill, downhill, or climbing stairs increases this to 3–4 times. Running raises it to 4 times, playing sports to about 6 times, and squatting or kneeling to approximately 8 times the body weight.

• Maintain a Healthy Weight: Keeping a suitable body weight reduces gravitational stress on the knee joint, as obesity also increases the risk of degenerative knee conditions.

• Strengthen Thigh Muscles: Studies abroad have shown that strong, well-developed muscles around the joint can reduce the incidence of osteoarthritis by 80% and delay its onset. The quadriceps muscles play a crucial role in stabilizing the knee joint. Strengthening them not only helps treat patellar chondromalacia but also minimizes abnormal knee joint impact, reducing the risk of osteoarthritis and maintaining knee health.

By paying attention to these points during exercise, you can enjoy the benefits of physical activity while minimizing damage to the knee cartilage—achieving multiple benefits at once.