Lateral Epicondylitis and Lateral Collateral Ligament Injury. Lateral epicondylitis, also called tennis elbow, is caused by degeneration and tearing of the common extensor ten-don.22 This condition often occurs as a result of repetitive sports-related trauma to the tendon, although it is seen far more commonly in nonathletes.9 In the typical patient, the degenerated extensor carpi radialis brevis tendon is partially avulsed from the lateral epicondyle.22 Scar tissue.
Tennis and gymnastics have been shown to have the highest likelihood of an isolated LCL injury.  The LCL can be sprained (grade I), partially ruptured (grade II) or completely ruptured (grade III) . 
tennis. A 2020 study notes that isolated collateral ligament injuries are rare. Due to complexity of the knee, injuries are more likely to involve other structures in the knee. It also notes that...
Lateral Knee Ligament Sprain (LCL) May 13, 2021. A lateral ligament sprain is a knee injury involving a tear to the ligament on the outside of the knee. It most commonly occurs following a direct blow to the inside of the knee. However, it can develop gradually through overuse.
Lateral collateral ligament (LCL) knee injuries are typically diagnosed by a sports medicine physician or other health care professional. A person should be prepared to answer questions, undergo a physical exam, and have medical imaging (such as an x-ray) performed.
Injury. Injuries to the LCL and posterior lateral corner result from a rotational force across the knee often with buckling of the knee. A contact injury, such as a direct blow to the medial side (inside of knee), or a noncontact injury, such as a hyperextension stress.
An LCL injury (a torn LCL or a LCL tear) is a strain or tear to the lateral collateral ligament (LCL). The LCL is a band of tissue that runs along the outer side of your knee .
The LCL is a narrow ligament which connects the femur (thigh bone) to the fibula on the outside of the knee. If the LCL is sprained, this means it is stretched, partially torn or in rare cases completely ruptured. Support strips of tape are applied along the length of the injured ligament to ‘reinforce’ it.