Knee Pain & Injuries: Causes and Treatment

ACL and meniscus tears, cartilage damage, arthritis and tendinitis. Find out what’s causing your knee pain and the treatment options, from physical therapy to surgery.

Medically reviewed by Dr. Nicolás Zarur · Updated October 2026

Knee pain can come from a sports injury, wear and tear, or a combination of both. Finding the exact cause is the first step to treating it well, and many knee problems improve without surgery.

Common symptoms

Pain on the inside, outside or front of the knee

Swelling or stiffness, especially in the morning

A knee that locks, catches or gives way

A pop at the moment of injury

Difficulty climbing stairs or kneeling

Pain that wakes you up at night

What causes knee pain?

ACL tear

A ligament injury common in football and other pivoting sports. The knee feels unstable.

Meniscus tear

Damage to the knee’s shock absorber after a twist, or from wear over time.

Cartilage damage

Injury to the smooth surface of the joint, which can lead to arthritis.

Knee osteoarthritis

Progressive wear of the joint that causes pain, stiffness and loss of motion.

Tendinitis and overuse

Irritation of the patellar or quadriceps tendon, common in runners and jumpers.

Fractures and trauma

Breaks around the knee after a fall or accident that need urgent care.

See a specialist soon if you:

How we diagnose and treat it

Dr. Zarur starts with a detailed exam and, when needed, an MRI or X-ray. Then he explains what’s going on and every option, from the most conservative to surgery.

Non-surgical

Rest, physical therapy, medication and injections. The first step for many knee problems.

Arthroscopy

Minimally invasive surgery to repair the meniscus, cartilage or ligaments through small incisions.

Reconstruction

Rebuilding a torn ligament such as the ACL to restore stability for sport.

Replacement

Partial or total knee replacement for advanced arthritis that no longer responds to other treatments.

Knee pain: frequently asked questions

If you can’t bear weight, the knee is very swollen, it locks, or the pain lasts more than two weeks, it’s time to see a specialist.

Not always. Dr. Zarur decides after examining you. If you already have an MRI, send it to us and we’ll review it.

Yes. Many cases improve with physical therapy, activity changes and medication. Surgery is recommended only when it’s the best option.

Mild soreness can be normal, but pain that keeps coming back or limits your running should be evaluated to prevent a bigger injury.

Yes. Our Tijuana office is minutes from San Diego, and we offer remote MRI review before you travel.

Let's find out what's causing your knee pain

Book a visit in Tijuana or Mexico City, or send us your MRI for a remote review.

Talk to Dr. Zarur's team

Get a clear diagnosis and honest options. We reply within one business day.

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Former President of the Mexican Football Federation’s Medical Commission and team physician for Cruz Azul, Morelia, Veracruz and Frontón México.