This article clarifies what a Medial Collateral Ligament (MCL) tear is and helps you recognize its common signs. Understanding these indicators can help you determine if your symptoms align with an MCL tear.
Understanding the MCL
The Medial Collateral Ligament (MCL) is a strong band of fibrous tissue on the inner side of the knee joint. It extends from the bottom of the thigh bone (femur) to the top of the shin bone (tibia). The MCL stabilizes the knee, preventing it from bending too far inward or experiencing excessive sideways movement.
Recognizing the Signs of an MCL Tear
Immediately following an MCL injury, many individuals report hearing or feeling a distinct “pop” or tearing sensation on the inner side of their knee. This is accompanied by sudden, sharp pain localized to the inner knee. The intensity of this initial pain can vary depending on the severity of the ligament damage.
Soon after the injury, swelling commonly develops around the affected area. Tenderness to the touch is also a symptom, particularly along the inner side of the knee. Bruising may appear within hours or days.
Individuals often experience knee instability, feeling as though the joint might “give out” or buckle, especially when putting weight on it or changing direction. This instability arises from the torn ligament’s compromised ability to stabilize the knee. The range of motion in the injured knee may become restricted, making it difficult or painful to fully bend or straighten the leg. Pain often worsens with activities that stress the MCL, such as twisting the knee or applying pressure to the outer side of the joint.
When to Seek Medical Attention
Seek medical attention if you experience significant pain on the inner side of your knee, especially after a direct blow or twisting injury. Consult a healthcare professional if you are unable to bear weight on the injured leg or if your knee feels unstable and prone to buckling. Prompt evaluation is also warranted if swelling is severe or if your range of motion is significantly limited.
Medical consultation is also recommended if your knee pain and other symptoms do not improve within a few days of rest and self-care. A medical professional can accurately assess the injury’s extent and determine the appropriate course of action. Early diagnosis helps ensure proper healing and prevents further knee damage.
Professional Diagnosis of an MCL Tear
A healthcare professional will begin the diagnostic process for a suspected MCL tear with a thorough physical examination. During this examination, the doctor will carefully palpate the inner side of your knee to pinpoint areas of tenderness and swelling. They will also assess your knee’s range of motion and stability.
A key part of the physical exam involves specific stress tests, such as the valgus stress test. In this test, the physician gently applies outward pressure to the knee while stabilizing the ankle, which stresses the MCL. The degree of gapping or laxity on the inner side of the knee during this maneuver helps determine the MCL tear’s severity. Increased gapping compared to the uninjured knee indicates ligament damage.
To rule out bone fractures or other structural issues, an X-ray may be ordered, although X-rays cannot visualize soft tissues like ligaments. For a definitive diagnosis of an MCL tear and to assess any associated injuries to other ligaments, cartilage, or meniscus, a magnetic resonance imaging (MRI) scan is often utilized. This comprehensive approach ensures an accurate diagnosis and guides the appropriate management plan.
References
1. Medial Collateral Ligament (MCL) Injury – OrthoInfo – AAOS. (n.d.). Retrieved August 4, 2025, from https://orthoinfo.aaos.org/en/diseases–conditions/medial-collateral-ligament-mcl-injury/
2. MCL Tear of the Knee: Symptoms, Diagnosis, and Treatment. (n.d.). Retrieved August 4, 2025, from https://www.verywellhealth.com/mcl-tear-of-the-knee-2549449