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Knee pain causes What is causing my knee pain, and how doctors find out
The most common knee pain causes are arthritis, kneecap (patellofemoral) pain, tendon irritation, meniscus or ligament injuries, bursitis, and fluid or a cyst in the joint. Where it hurts is a strong clue: pain at the front often points to the kneecap or patellar tendon, the inside to arthritis or the meniscus, the outside to the IT band, and the back to a Baker’s cyst. An exam and, when needed, an in-office ultrasound or an X-ray confirm the cause.
“What is causing my knee pain?” is one of the questions our clinicians hear most. The answer shapes everything that follows, because a worn joint, an irritated tendon and a torn meniscus need different plans. The videos above show two ways we look inside the knee in the office: an ultrasound that finds a cyst behind the knee, and an ultrasound-guided procedure that removes fluid from a swollen knee. For every knee problem we treat, see our knee pain treatment page.
Knee pain causes by location
Front of the knee
- Patellofemoral pain: an ache around or behind the kneecap, worse on stairs, squats or after sitting; see knee pain on stairs and knee pain when bending
- Patellar tendon pain (jumper’s knee): pain just below the kneecap with jumping or running
- Bursitis: a soft, swollen bump over the kneecap, often from kneeling
Inside of the knee
- Osteoarthritis: wear is most common on the inner side, with morning stiffness and pain after activity
- Medial meniscus tear: pain along the joint line, sometimes with catching or swelling
- MCL sprain or pes anserine bursitis: tenderness a little below or along the inner knee
Outside of the knee
- IT band irritation: a burning ache on the outer knee with running or cycling
- Lateral meniscus or ligament injury: usually after a twist or a blow
Back of the knee
- Baker’s cyst: a fluid-filled swelling behind the knee, often linked to arthritis or a meniscus problem inside the joint, as the first video shows
- Tendon strain: at the hamstring or calf attachments (see hamstring strain recovery)
- Blood clot: uncommon, but calf pain and swelling need same-day care
Clues from how it started
- A pop and fast swelling during sport often means a ligament injury, such as an ACL tear
- A twist followed by catching or locking suggests a meniscus tear
- Gradual pain with morning stiffness points to arthritis
- A hot, red, very swollen knee without an injury can be gout or infection and needs urgent care
How a knee pain doctor finds the cause
Most of the answer comes from the history and a hands-on exam that tests the ligaments, meniscus, kneecap and tendons. An X-ray shows arthritis and bone problems. Diagnostic musculoskeletal ultrasound lets a clinician see tendons, fluid and cysts in real time in the office, as in the first video. An MRI is ordered when a tear is suspected and the result would change the plan.
When a knee is swollen, removing the fluid relieves pressure and lets it be checked for signs of gout or infection. The second video shows fluid drawn off under ultrasound guidance. Read more about knee aspiration and draining fluid from the knee.
What happens once you know the cause
Kneecap and tendon pain usually respond to targeted strengthening; see physical therapy for knee pain. Many meniscus tears improve with therapy too. For osteoarthritis, our guide to knee arthritis treatment explains what helps at each stage. Arthritis plans combine exercise, weight and activity changes and, when needed, joint injections, knee gel injections or a genicular nerve block and ablation. If pain has already lasted months, our guide to chronic knee pain treatment goes further. Physical therapy is offered at our Brooklyn and Staten Island offices.
When to see a knee pain doctor
Get the knee checked if you cannot put weight on it, it locks or gives way, swelling keeps coming back, or pain lasts more than a few weeks. Get same-day care for a hot, red, swollen knee with fever, or for pain and swelling in the calf.
More videos on finding the cause of knee pain
More clips from our YouTube channel @precisioncaremedical showing how ultrasound helps find the cause of knee pain.
Related care at Precision Care Medical & Sports Performance
A knee pain doctor near you
Precision Care Medical & Sports Performance physicians evaluate knee pain at all three offices. For knee pain treatment in Brooklyn, Ashley Marcus, MD sees patients at our Brooklyn office near Bensonhurst, Gravesend and Coney Island, where physical therapists Zoya Reznik, DPT, OCS and Maggie (Yi) Zhang, DPT, with physical therapist assistants Dennis Furman, PTA and Leila Nahmoud, PTA provide physical therapy in Brooklyn. For knee pain on Staten Island, Jake Stephen, DO sees patients at our Staten Island office, convenient to New Dorp, Oakwood and Eltingville, with physical therapists Victoria Lynn Kain, DPT and Nicholas “Nick” Ursini, DPT for physical therapy on Staten Island.
In Manhattan, Yuri Gordin, MD sees patients at the Precision Care Spine & Pain Center in Midtown Manhattan, close to Harlem, the Upper East Side, Spanish Harlem and Washington Heights. Physical therapy is not offered at the Midtown Manhattan office. Pain procedures are performed at all three offices, and your physician explains where and when yours will be scheduled. Searching for a knee pain doctor near me? Request an appointment or call the office closest to you.
150 E 55th St, Suite 401, New York, NY 10022
(212) 840-0135
Questions patients ask
What is the most common cause of knee pain?
In adults, osteoarthritis and kneecap (patellofemoral) pain are among the most common. In active people, tendon irritation and meniscus or ligament injuries are also common.
What does pain at the back of the knee mean?
It is often a Baker’s cyst, a fluid-filled swelling linked to arthritis or a meniscus problem inside the joint. Hamstring or calf tendon strain is another cause. Calf pain and swelling can rarely be a blood clot and needs same-day care.
What does pain on the inside of the knee mean?
Common causes are osteoarthritis, a medial meniscus tear, an MCL sprain and pes anserine bursitis. An exam usually tells them apart, and imaging is added when needed.
Do I need an MRI for knee pain?
Not always. Many causes are clear from the history, exam, X-ray or an in-office ultrasound. An MRI is ordered when a tear is suspected and the result would change the plan.
Why does my knee keep swelling?
Repeated swelling usually means something inside the joint is irritated, such as arthritis, a meniscus tear or, less often, gout. Removing and checking the fluid can help find the cause.
Where can I find a knee pain doctor near me?
Precision Care Medical & Sports Performance physicians see knee pain in Brooklyn at 2781 Shell Rd, Suite 101, (718) 648-1234, on Staten Island at 1630 Richmond Rd, Suite 101, (718) 339-7100, and in Midtown Manhattan at 150 E 55th St, Suite 401, (212) 840-0135. Physical therapy is offered in Brooklyn and Staten Island.
Educational only, not medical advice. These videos and this article explain common problems and treatments in general terms. They are not a diagnosis or a treatment plan for you. Results vary from person to person. See a qualified clinician about your own symptoms, and call 911 or go to an emergency room for an emergency.
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