ACL, MCL, and Meniscus Tears: What’s the Difference?

If you’ve ever experienced sudden knee pain, swelling, or instability—especially during sports or physical activity—you may be dealing with an injury to one of three key knee structures: the ACL, MCL, or meniscus.

While the symptoms can overlap, each structure plays a different role in stabilizing your knee. Understanding the differences can help you get the right diagnosis and treatment.

At BASS Medical Group, our experienced orthopedic team—including sports medicine specialist Dr. Benjamin Busfield—treats knee injuries with both non-surgical and surgical approaches.

What Is the ACL?

The anterior cruciate ligament (ACL) is one of four major ligaments in the knee. It stabilizes the joint by preventing your tibia (shinbone) from sliding too far forward and helps control twisting motions.

Signs of an ACL Tear:

• A loud pop or sensation during injury
• Sudden severe pain
• Rapid swelling within hours
• A feeling like the knee is giving out
• Difficulty walking or bearing weight

ACL injuries commonly happen during activities that involve jumping, pivoting, or quick direction changes—think basketball, soccer, or skiing.

What Is the MCL?

The medial collateral ligament (MCL) runs along the inside of the knee and helps stabilize the joint against pressure from the outer side. MCL injuries are often caused by a blow to the outer knee (common in football or hockey).

Signs of an MCL Tear:

• Pain and tenderness along the inner knee
• Swelling or bruising
• Instability when putting weight on the leg
• Occasional locking or stiffness

Unlike ACL tears, MCL injuries typically don’t involve a popping sound. However, both injuries may cause knee instability and swelling.

What Is the Meniscus?

The meniscus is a crescent-shaped piece of cartilage that acts as a cushion between the thighbone and shinbone. You have two menisci in each knee. Meniscus tears often occur during twisting or over-flexion of the knee.

Symptoms of a Meniscus Tear:

• Localized pain (especially when twisting the knee)
• Swelling and stiffness
• Difficulty bending or straightening the knee
• A feeling of the knee locking or catching

While ACL and MCL tears often happen from trauma, meniscus tears can also result from age-related wear and tear.

ACL vs MCL vs Meniscus: How to Tell the Difference

Regardless of the cause, always consult an orthopedic specialist or primary care provider (PCP) if you suspect a knee injury.

Treatment Options for Knee Injuries

ACL Tear Treatment

• Physical therapy to rebuild strength and stability
• ACL reconstruction surgery for complete tears
• Full recovery may take 6 to 12 months

MCL Tear Treatment

• Rest, bracing, and anti-inflammatory medication
• Physical therapy for moderate injuries
• Surgery is rare unless combined with other ligament injuries
• Recovery time: 4 to 8 weeks, depending on severity

Meniscus Tear Treatment

• R.I.C.E. method (Rest, Ice, Compression, Elevation)
• Physical therapy and anti-inflammatory meds
• Minimally invasive surgery (arthroscopy) if needed
• Recovery: 6 weeks to 3 months, longer if surgery is needed

For more details, learn about sports medicine and orthopedic surgery at BASS Medical Group.

Get a Professional Diagnosis and Imaging

If you’re experiencing knee pain, swelling, or instability, early diagnosis is key. At BASS Medical Group, we offer:

• Appointments with orthopedic surgeons and sports medicine specialists
• Referrals from your Primary Care Provider (PCP)
• In-house imaging services at the BASS Imaging Center in Walnut Creek for quick results
• Minimally invasive surgical options, including arthroscopy

Ready to take the next step?
Request an appointment or find a specialist near you.