Knee Pain: Diagnosis and Treatment Options

How the cause of knee pain is found

Finding the cause guides treatment. If you are trying to work out what your symptoms mean, our page on knee pain causes by location is the place to start.

A doctor will:

1. Ask about onset, injury mechanism, swelling, locking and instability, and other joints.
2. Examine the knee: alignment, swelling, range of motion, tenderness along the joint line, ligament stress tests, kneecap tracking, and the hip.
3. Order tests when needed: - Standing X-rays for arthritis, fractures and alignment. - MRI for suspected meniscus, ligament or cartilage injuries, when the result would change treatment. - Joint aspiration of a hot swollen knee for crystals (gout) or infection. - Blood tests if inflammatory arthritis is suspected.

Clinical guidelines advise against routine MRI for knee pain in people over about 40 with typical osteoarthritis, because degenerative meniscus tears and cartilage changes are common on scans in people without pain.

Exercise: the most effective long-term treatment

Strengthening the thigh (quadriceps), hamstring and hip muscles reduces pain and improves function in osteoarthritis, patellofemoral pain and after many injuries. A physical therapist can tailor a program, but common exercises include:

• Straight leg raises: lie on your back, tighten the thigh and lift the straight leg to the height of the other bent knee.
• Sit-to-stand: rise from a chair without using your hands, slowly.
• Wall squats or mini-squats to a comfortable depth.
• Step-ups onto a low step.
• Side-lying leg raises and clamshells for the hip muscles, which control knee alignment.
• Bridges for hamstrings and glutes.
• Low-impact cardio: cycling, swimming, water walking.

Expect improvement over 6 to 12 weeks. Mild discomfort during exercise is acceptable if it settles within 24 hours.

Medicines

• Topical NSAID gels (such as diclofenac) are recommended as a first choice for knee osteoarthritis, especially over age 75, with fewer side effects than tablets.
• Oral NSAIDs such as ibuprofen or naproxen, at the lowest effective dose for the shortest time, following the label. Avoid them with kidney disease, stomach ulcers, heart failure or blood thinners.
• Acetaminophen (paracetamol) has a small effect in osteoarthritis but is safe for many people.
• Duloxetine is sometimes prescribed for chronic osteoarthritis pain.
• Opioids are not recommended for long-term knee pain.

Weight loss

For people with overweight and knee osteoarthritis, losing 5 to 10% of body weight meaningfully reduces pain and improves function. Each pound of weight lost removes about 4 pounds of force from the knee with every step.

Braces, supports and aids

• Knee sleeves give warmth and a sense of support.
• Unloader braces shift load away from the worn side of the knee in one-sided arthritis.
• Patellar taping or bracing helps some people with patellofemoral pain.
• A cane held in the hand opposite the painful knee reduces load.
• Cushioned, supportive footwear.

Injections

• Corticosteroid injections give short-term relief (weeks to a few months) in arthritis flares. Repeated frequent injections are generally limited.
• Hyaluronic acid injections: evidence of benefit is weak, and several guidelines do not recommend them routinely.
• Platelet-rich plasma (PRP) and stem cell injections: evidence is still uncertain, and they are not standard recommendations.

Surgery

• ACL reconstruction: for young or active people with instability after an ACL tear.
• Meniscus repair: for tears in younger people, especially those causing a locked knee.
• Arthroscopic "clean-out" (debridement) for arthritis or degenerative meniscus tears: studies show it adds little over physical therapy for most people, so it is no longer routinely recommended.
• Osteotomy: realigning the bone in younger people with one-sided arthritis.
• Partial or total knee replacement: for advanced arthritis with severe pain and disability despite non-surgical care. Most people have major pain relief, and modern implants commonly last 20 years or more. Recovery takes about 3 months, with improvement continuing for a year.

Outlook

Most acute knee strains and overuse problems settle within weeks to a few months. Knee osteoarthritis is long-term but often stable for years with exercise and weight management. Pain levels fluctuate, and flares usually settle.

Preventing knee pain

• Build up training gradually, by no more than about 10% a week.
• Keep thigh and hip muscles strong.
• Learn safe landing and pivoting techniques in sport. Injury prevention programs reduce ACL tears in young athletes.
• Maintain a healthy weight.
• Replace running shoes regularly.

Frequently asked questions

What is the best treatment for knee pain?

For most long-term knee pain, including osteoarthritis and patellofemoral pain, the most effective treatment is a structured strengthening program combined with weight loss if needed and simple pain relief. Injections and surgery are reserved for specific injuries or severe arthritis.

Should I rest or exercise a painful knee?

Rest from activities that clearly worsen pain for a few days after an injury, but keep the knee moving. For chronic knee pain, regular exercise is better than rest. Choose low-impact options such as cycling and swimming and build up gradually.

Do knee braces help knee pain?

Some do. Unloader braces help one-sided arthritis, and patellar braces or taping help some kneecap problems. Simple sleeves add comfort. Braces work best alongside exercise, not as a replacement for it.

When is knee replacement needed?

Knee replacement is considered when advanced osteoarthritis on X-ray causes severe pain and disability, such as limited walking or night pain, despite exercise, weight loss, medicines and injections. It is a decision based on quality of life rather than age alone.

Do steroid injections damage the knee?

Occasional steroid injections are generally safe and relieve arthritis flares for weeks to months. Very frequent injections over years may speed cartilage loss, so doctors usually limit how often they are given.