It collaborates with other ligaments and muscles in the knee to control lateral movement of the knee joint and prevents excessive motion that can prove detrimental. Additionally, it has been noted that LCL injury rarely occurs in isolation and is often accompanied by other injuries in the knee joint. 

An injury to the LCL can range from mild stretching to complete tearing of the ligament. Like other ligament injuries, LCL injuries can be classified into different grades based on the severity of the injury. 

The 3 grades of LCL injuries are:

• Grade 1: mild LCL injury, where the ligament is stretched but not torn. This can cause some pain and tenderness on the outer side of the knee but usually does not result in significant instability.
• Grade 2: moderate LCL injury, where the ligament is partially torn. This can cause pain, swelling, and some instability in the knee, making it difficult to bear weight or perform activities that require knee movement.
• Grade 3: severe LCL injury, where the ligament is completely torn. This can cause significant pain, swelling, and instability in the knee, making it difficult or impossible to bear weight or move the knee joint. A grade 3 LCL injury may also be associated with damage to other structures in the knee, such as the meniscus or other ligaments.

These include:

• Sudden change of direction that places strain on the ligament
• Hyperextension of the knee joint
• Twisting motion that puts excessive stress on the ligament
• Sports such as football, basketball, and skiing
• Car accidents or other traumatic events that cause a blow to the knee
• Chronic overuse and repetitive stress on the knee joint
• Abruptly stopping when moving in a fast motion
• Direct and heavy contact at the knee

• A “pop” or “snap” when an injury occurs (severe cases)
• Swelling and tenderness
• Bruising and discolouration around the affected area
• Stiffness and limited range of motion
• Difficulty conducting any form of movement (walking, running)
• Generally feeling unstable and the sensation of your leg “giving away” or buckling

If the injury is not addressed or if the healing process is hindered by factors such as age, poor circulation, or smoking, pain may persist. The level of pain, however, varies according to the extent of the injury, with small sprains causing relatively modest discomfort while tears causing intense pain that may make it impossible to place weight on the afflicted leg or move the knee joint.

• Athletes: LCL injuries are common among athletes of football, rugby, and basketball.  
• Gender: women athletes are more prone to LCL injuries potentially attributed to the anatomical difference of the lower extremities, looseness of ligaments, and other physical conditioning.
• Medical history: individuals with pre-existing knee conditions or those hereditary predisposed to LCL injuries, have a higher risk of being susceptible to LCL injuries.

• Physical examination and medical history: inform your orthopaedist of the potential activities that may have led to an injury such as trauma, exercise, or sports. Physically the area of injury will be examined and several motion tests will be conducted to review the injury. ‍
• Imaging tests: magnetic resonance imaging (MRI) or dynamic ultrasonography would be required to examine if surrounding areas of the LCL are impacted given the likelihood of LCL injury being accompanied by other forms of injury. An x-ray would be conducted if a fracture is suspected. A specific type of radiography, stress radiography, would be conducted where an x-ray is taken while a force is being applied to the knee joint to assess its stability.‍
• Arthroscopy: arthroscopy, a minimally invasive procedure will be conducted where a small camera is inserted into the knee joint to visualise the structures inside.

• Rest: you would be advised to observe complete rest, while icing the afflicted area, to relieve pain and reduce swelling.
• Medications: non-steroidal anti-inflammatory drugs (NSAIDs) and painkillers are commonly prescribed as the first course of treatment to reduce inflammation and manage pain.
• Brace: to reduce movement of the joint and allow the ligament to heal.
• Crutches: to limit placing weight on the affected knee.
• Physiotherapy: upon discontinuation of the use of the brace, an active range of motion exercise would be administered via physiotherapy to regain mobility and strengthen muscle.
• Surgery: knee arthroscopy surgery would be administered if deemed necessary to restore the structure of ligament damage.