What are the different types of knee pain, and what are their respective causes? What are the best treatments, care routines, health maintenance methods, medications, health devices, and fitness equipment? What specific behaviors should be avoided?

The causes of knee pain are very diverse, ranging from acute injuries to chronic strain. The following content is organized based on authoritative medical sources (Mayo Clinic, Merck Manual) for your reference.

Table of Contents

🦵 What Types of Knee Pain Are There? What Are the Causes of Each?

Knee pain can be broadly divided into injury-related, mechanical, arthritis-related, and other categories.

1. Injury-related (more common in acute cases)

ACL (anterior cruciate ligament) injury: Common in sports requiring sudden stops and changes of direction, such as basketball and soccer.
Meniscus tear: Caused by sudden twisting while the knee is bearing weight; the cartilage that acts as a shock absorber is damaged.
Fracture: Falls or car accidents can cause fractures of the kneecap (patella), etc.; people with osteoporosis may even fracture from a misstep.
Patellar tendinitis: Inflammation of the tendon connecting the patella to the tibia, more common in runners, skiers, and jumping athletes.
Knee bursitis: Inflammation of the bursae around the knee that provide cushioning.

2. Mechanical Problems

Loose body: Fragments of bone or cartilage that break off and “float” in the joint cavity, possibly locking the joint.
Iliotibial band syndrome: The tough band of tissue extending from the outside of the hip to the outside of the knee becomes too tight and rubs against the outer femur; highly common in long-distance runners and cyclists.
Patellar dislocation: The kneecap slips out of its normal position, usually displacing outward.
Patellofemoral pain syndrome (chondromalacia patellae): Softening of the cartilage under the kneecap, presenting as dull pain around and behind the knee, worsening with stairs and after prolonged sitting, usually without swelling. Especially common in adolescent runners.
Hip/foot pain: May alter gait, thereby transferring more pressure to the knee joint and causing knee pain.

3. Arthritis-related

Osteoarthritis: The most common type; joint cartilage wears and degenerates with age and use.
Rheumatoid arthritis: An autoimmune disease that can affect almost any joint, including the knee.
Gout and pseudogout: Caused by the deposition of urate crystals (gout) or calcium-containing crystals (pseudogout) in the joint. The joint most commonly affected by pseudogout is the knee.
Septic arthritis: Infection of the knee joint, usually accompanied by fever, and generally no trauma before onset. Requires immediate medical attention, otherwise it will rapidly destroy cartilage.

🚨 When Should You Seek Emergency Medical Care?

If any of the following occurs, seek medical attention or go to the emergency department as soon as possible:

The knee is bent or deformed
A popping sound was heard at the time of injury
The knee cannot bear weight
Severe pain
The knee suddenly swells

If the knee is severely swollen, red, warm, and tender, or accompanied by fever, you should also contact a doctor promptly.

💊 Medications

Topical first: For mild pain, first try topical creams or gels. Products containing 10% menthol or diclofenac can relieve pain without oral medication.

Oral medications (if topicals are ineffective):

Non-steroidal anti-inflammatory drugs (NSAIDs): Such as ibuprofen and naproxen sodium, which can reduce pain and swelling.
Acetaminophen: If you have kidney disease, high blood pressure, are over 75 years old, or are prone to stomach upset, choose acetaminophen instead of NSAIDs.

Note: NSAIDs may increase the risk of heart attack, stroke, and gastrointestinal bleeding. Long-term use should be under medical guidance.

Injections (performed by a doctor):

Corticosteroid injections: Reduce inflammation and pain during acute arthritis flare-ups; effects can last weeks to months.
Hyaluronic acid injections: A thick liquid similar to the joint’s natural lubricant, which can improve mobility and relieve pain.
Platelet-rich plasma (PRP): Contains various growth factors. Some studies show benefits for certain osteoarthritis patients, but evidence is still insufficient.

🧘 Health Maintenance Methods and Care

Home self-care (suitable for mild knee pain without obvious trauma):

Rest the knee: Minimize standing; use a cane or walker if necessary.
Ice: Apply an ice bag wrapped in a towel to the knee for 15–20 minutes each time, several times a day.
Compression: Use an elastic bandage or knee sleeve for support, snug but not too tight.
Elevate the affected knee: When lying down, prop the knee up with a pillow, above heart level.
Switch to low-impact exercise: Replace jogging with swimming, and tennis with cycling. Low-impact exercise and weight loss help treat painful knee arthritis.

Physical therapy and exercise: Strengthening the muscles around the knee can enhance stability. Doctors may recommend physical therapy or targeted strengthening exercises based on the specific cause. Exercises to improve flexibility and balance are equally important.

Specific care for chondromalacia patellae: Doctors usually recommend quadriceps strengthening and stretching exercises, ice, and NSAIDs if necessary. Activities that worsen pain (usually those involving knee bending) should be avoided as much as possible for several days.

🦾 Supports and Exercise Equipment

Knee braces and arch supports:

Different types of knee braces can be used to protect and support the knee joint.
Arch support insoles (sometimes with a wedge added to one heel) can help transfer pressure away from the side most affected by osteoarthritis.

Exercise equipment:

Knee rehabilitation and strengthening usually do not rely on complex equipment. Basic tools such as resistance bands and yoga mats are sufficient for low-load resistance training and core/lower limb stability exercises.
Low-impact aerobic equipment such as stationary bikes and elliptical machines are relatively friendly to the knee joint.

⚠️ Behaviors That Particularly Need to Be Avoided

Ignoring red flag symptoms: If knee pain is accompanied by fever, obvious swelling, redness, or inability to bear weight, do not handle it on your own — seek medical attention immediately.
Forcing activity after acute injury: If a popping sound was heard at the time of injury, the knee is deformed, or it cannot bear weight, avoid continuing to use the affected knee and seek medical attention as soon as possible.
Forcing exercise during the acute pain phase: In conditions such as chondromalacia patellae, activities that worsen with knee bending should be avoided as much as possible for several days.
Long-term dependence on knee braces: Knee braces can provide support during specific activities, but long-term dependence may weaken the knee’s own muscle strength. They should be used under the guidance of a doctor or physical therapist.
Continuing high-impact exercise while obese: Body weight increases the load on the knee joint. Weight loss is one of the important measures for reducing knee arthritis pain.