ACL Tears: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats ACL Tears?
An orthopedic surgeon (a bone and joint doctor) or a sports medicine doctor treats ACL tears. You may also see a physical therapist (a movement expert) for rehab. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What are ACL tears?
Your knee has four main ligaments. Ligaments are strong bands that connect the thigh bone (femur) to the shin bone (tibia) and keep the knee steady. The anterior cruciate ligament (ACL) sits in the middle of the knee. It stops the shin bone from sliding too far forward.
A tear happens when the ligament is stretched past its limit. It can be a partial tear or a complete tear. Most ACL tears happen in the middle of the ligament or pull off the thigh bone. They do not heal on their own.
Symptoms
When you tear your ACL, you may hear a popping sound. Your knee may give way from under you. Other symptoms include:
- Pain and swelling. The knee swells within 24 hours.
- Loss of full range of motion. It can be hard to fully bend or straighten the knee.
- Tenderness along the joint line.
- Discomfort while walking.
- Trouble continuing your sport.
An ACL tear often comes with other injuries. These include a torn meniscus (the knee's shock absorber) or a torn medial collateral ligament (the ligament on the inner knee).
Causes and who gets it
The ACL can be injured in several ways:
- Changing direction fast.
- Stopping suddenly.
- Slowing down while running.
- Landing from a jump wrong.
- A direct hit or collision, such as a football tackle.
These moves are common in volleyball, soccer, football, and basketball. Skiing is also linked to ACL tears. Anyone can tear an ACL, but women tear it more often than men. Risk factors include a higher body mass index (BMI, a weight measure), looser joints, and weaker leg muscles.
How doctors diagnose it
Your provider may send you to get an MRI (a scan that uses magnets) of the knee. It can confirm the diagnosis. It may also show other knee injuries.
Doctors grade the sprain from 1 to 3. Grade 1 is a mild stretch, and the ACL is still able to hold the knee steady. Grade 2 is a partial tear, where the ligament becomes loose. Grade 3 is a complete tear, and the knee joint is unstable.
Treatment
Treatment depends on how active you are, how bad the tear is, how unstable your knee feels, and whether other parts of the knee are hurt.
Partial tears may be treated without surgery. Care may include physical therapy, ice, raising your leg above your heart, and pain relievers such as ibuprofen or naproxen. A knee brace may add support.
Complete tears usually need surgery to rebuild the ligament. The torn ACL is generally reconstructed rather than repaired. The surgeon replaces it with a tendon graft. The graft comes from your own body (autograft) or from a tissue donor (allograft).
Active adults who do pivoting or cutting sports or heavy manual work are encouraged to consider surgery. Activity level, not age, should decide this. Physical therapy is a crucial part of successful ACL surgery. Most people return to full sports in 6 to 12 months.
After surgery, pain medicine may include opioids (strong pain pills). These can be addictive and potentially dangerous. Use them only as your doctor directs, as little as possible, and stop as soon as your pain improves.
When to see a doctor
See your provider right away after a serious knee injury. Do not return to play or other activities until you have been treated. Call 911 or go to the emergency room if your foot is cool and blue after a knee injury. This can mean the knee joint is dislocated and blood vessels are hurt. It is a medical emergency.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. This kind of doctor can check the knee first and may send you to get an MRI. They can also refer you to an orthopedic surgeon when needed.
Common questions
Can a torn ACL heal without surgery?
Most ACL tears do not heal on their own. Partial tears may be treated with physical therapy. Complete tears usually need surgery to rebuild the ligament.
How long until I can play sports again?
Most people return to full sports in 6 to 12 months after surgery. You should have no pain or swelling and full knee motion first. Muscle strength and balance should be back too.
Do knee braces prevent ACL injuries?
Not specifically. Braces during hard activity are controversial. They have been shown to reduce some knee ligament injuries, but not specifically ACL injuries.
Who is most likely to tear an ACL?
Anyone can. Women tear the ACL more often than men. Risk factors include a higher BMI (a weight measure), looser joints, and weaker leg muscles.
Sources
- American Academy of Orthopaedic Surgeons - Anterior Cruciate Ligament (ACL) Injuries
- American Academy of Orthopaedic Surgeons - ACL Injury: Does It Require Surgery?
- MedlinePlus - Anterior cruciate ligament (ACL) injury
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
