MCL Tears

An MCL tear occurs when the ligament fibers are stretched or torn due to excessive stress placed on the inside of the knee. This injury can range in severity from a mild sprain, where the ligament fibers are stretched but intact, to a complete rupture, where the ligament is fully torn. The MCL is critical for maintaining medial knee stability, so a tear can significantly affect a person’s ability to walk, run, or pivot.

MCL injuries are often isolated, but they can also occur in conjunction with other knee injuries including anterior cruciate ligament (ACL) tears or meniscus damage. Because the MCL receives a strong blood supply, it tends to heal better than other ligaments in the knee, but the recovery process still depends on the extent of the tear and the presence of associated injuries.

The symptoms of an MCL tear vary depending on the degree of injury. A person with a mild sprain may experience only localized pain and tenderness, while a complete tear can cause significant instability and difficulty bearing weight. Common symptoms include:

• Pain along the inner side of the knee
• Swelling and tenderness near the ligament
• A feeling that the knee may “give out” or buckle under stress
• Stiffness and limited range of motion
• Bruising around the inner knee
• Difficulty walking or bending the knee

In severe cases, patients may hear or feel a “pop” at the moment of injury, followed by immediate pain and swelling. Because symptoms can overlap with other knee injuries, a professional evaluation is essential to determine the exact nature of the damage.

MCL tears are most often caused by a force applied to the outside of the knee, which pushes the joint inward and overstretches the ligament. This type of injury mechanism is frequently seen in contact sports such as football, soccer, hockey, and basketball, where collisions or tackles can produce a valgus stress on the knee. Non-contact mechanisms, such as twisting or pivoting suddenly on a planted foot, can also lead to injury.

Risk factors for MCL tears include:

• Participation in high-impact or contact sports
• Poor conditioning or weak hip and thigh muscles
• Improper landing or pivoting techniques
• Previous knee injuries
• Playing on uneven surfaces or in slippery conditions
• Wearing inappropriate or worn-out footwear

In older adults, degenerative changes in the knee joint can also make the MCL more susceptible to injury from relatively minor trauma or falls.

Untreated or improperly managed MCL tears can lead to chronic knee instability, increasing the risk of future injuries. Persistent instability may also cause compensatory stress on other structures in the knee, such as the meniscus or cartilage, potentially leading to early joint degeneration or osteoarthritis. Recurrent sprains or partial healing of the ligament can further weaken the knee, limiting athletic performance and daily function.

In cases where the MCL tear occurs alongside an ACL or meniscus tear—a pattern known as the “unhappy triad”—the risk of long-term complications and joint instability rises significantly. Early diagnosis and appropriate treatment are therefore crucial to prevent lasting damage and ensure optimal recovery.

Diagnosing an MCL tear begins with a thorough clinical examination by Dr. Kevin Collon. The evaluation includes a detailed discussion of the patient’s injury history, symptoms, and the specific mechanism of injury. During the physical exam, he will perform targeted maneuvers to assess the integrity of the MCL. The most common test is the valgus stress test, in which the doctor gently pushes the lower leg outward while stabilizing the thigh to evaluate for pain, laxity, or instability along the inner knee.

Additional imaging studies help confirm the diagnosis and rule out associated injuries.

• X-rays are used to exclude bone fractures or avulsion injuries (where a piece of bone is pulled away by the ligament).
• Magnetic resonance imaging (MRI) provides the most accurate visualization of soft tissues, allowing the physician to determine the grade of the tear, identify any concurrent ligament or meniscus injuries, and guide treatment planning.
• Ultrasound may also be used in some settings to evaluate the ligament in real time and assess healing progress.

The severity of the injury is typically classified into three grades:

• Grade 1 (Mild): Minor stretching or microscopic tearing of the ligament fibers with localized tenderness but no instability.
• Grade 2 (Moderate): Partial tearing with noticeable pain, swelling, and mild to moderate looseness of the joint.
• Grade 3 (Severe): Complete tear with significant instability, swelling, and difficulty bearing weight.

This grading helps determine the most appropriate treatment approach and recovery timeline.