Understanding MCL Injury Treatment: When is Surgery the Right Choice?

Understanding MCL Injury Treatment: When is Surgery the Right Choice?


Medial Collateral ligament (MCL) injuries are common among athletes and physically active individuals. The MCL is a critical ligament located on the inner side of the knee, providing stability and preventing excessive movement. Injuries to the MCL are typically categorised into three grades, with treatment options ranging from conservative management to surgical intervention. This article aims to explain when surgery is necessary for an MCL injury and why it is not always the first choice, while also delving into the biology, physics, and rehabilitation involved in the healing process.

Understanding MCL Injuries

The grading of MCL tears helps determine the appropriate treatment strategy:

  • Grade I MCL Tear: Involves minimal damage, with 0-10% of the ligament fibers affected. These tears usually do not cause significant instability and can be managed with rest, ice, compression, and physical therapy. The injury often results from a mild valgus force, such as a non-contact twisting motion.
  • Grade II MCL Tear: Involves a partial tear, affecting 10-90% of the fibers, resulting in mild to moderate instability. These tears can occur from a more forceful valgus stress, such as a direct blow to the knee. Treatment typically includes immobilisation followed by a progressive rehabilitation program.
  • Grade III MCL Tear: A complete tear with little to no intact fibers, leading to significant instability. These injuries are often due to severe valgus forces from high-energy impacts or sports-related incidents. Surgical intervention may be required, particularly if there are associated injuries like ACL tears.

Why Surgery Isn't the First Option

surgery for MCL injuries is often reserved for specific cases due to several reasons:

  1. Successful Non-Surgical Treatments: Many MCL injuries, especially Grade I and II, respond well to conservative treatments such as physical therapy, bracing, and rest. These methods help restore knee function and stability without the need for surgical intervention.
  2. Natural Healing Ability: The MCL has a good blood supply, which promotes natural healing. With appropriate rehabilitation, the ligament can often heal on its own, especially in less severe injuries.
  3. Risks and Recovery Time: Surgery carries inherent risks, including infection, complications from anesthesia, and a longer recovery period. Non-surgical treatments are generally safer and allow for a quicker return to daily activities.

The Physics and Biology of MCL Healing

Understanding the biomechanics and biology of the MCL is essential in appreciating why non-surgical treatments are often preferred:

  • Biomechanics: The MCL stabilises the knee by resisting valgus forces. When injured, a knee brace can help distribute these forces, reducing stress on the healing ligament and preventing further damage. The physics of bracing supports the injured area, allowing for controlled movement and promoting recovery.
  • Biology: The MCL's rich blood supply aids in the healing process. Fibroblasts, the cells responsible for producing collagen, migrate to the injury site, rebuilding the ligament tissue. This biological response is enhanced by physical therapy, which encourages proper alignment and strength of the new fibers.

When is Surgery Necessary?

Surgical intervention is considered in specific scenarios:

  • Severe Grade III Tears: When there is significant instability or a complete tear, especially if the injury is combined with damage to other ligaments or structures in the knee.
  • Persistent Instability: If non-surgical treatments fail to restore stability and function, surgery may be required to repair or reconstruct the ligament.
  • Chronic MCL Deficiency: In cases where the ligament does not heal properly, leading to long-term instability and knee problems.


While surgery is sometimes necessary for severe MCL injuries, most cases can be effectively managed with non-surgical treatments. Understanding the biology and biomechanics of MCL healing highlights the effectiveness of conservative approaches, emphasizing the body's natural ability to repair itself. For many patients, a combination of bracing, physical therapy, and time can lead to a full recovery without the need for surgery.


  1. What are the common symptoms of an MCL injury? Symptoms include pain, swelling, and instability on the inner side of the knee, often worsening with activity or pressure.

  2. How long does it take to recover from an MCL injury? Recovery time varies; Grade I injuries may heal in a few weeks, while Grade II and III injuries can take several months.

  3. Can I continue to exercise with an MCL injury? Light activities may be possible with a knee brace, but it's crucial to follow a healthcare provider's advice to avoid worsening the injury.

  4. What role does a knee brace play in MCL rehabilitation? A knee brace helps stabilize the knee, reducing stress on the MCL and allowing for controlled movement during the healing process.

  5. When should I consider surgery for an MCL injury? surgery is considered for severe Grade III tears, persistent instability despite non-surgical treatments, or chronic MCL deficiency.

  6. How effective are non-surgical treatments for MCL injuries? Non-surgical treatments are highly effective for many MCL injuries, promoting natural healing and restoring knee function without the risks associated with surgery.