Overview
The lateral collateral ligament (LCL) goes from the top part of the fibula (the bone on the outside of the lower leg) to the outside part of the lower thigh bone. The ligament helps keep the outer side of the knee joint stable.
Causes
The LCL is usually injured by pressure or an injury that pushes the knee joint from the inside, which results in stress on the outside part of the joint.
Symptoms
Knee swelling
Locking or catching of the knee with movement
Pain or tenderness along the outside of the knee
Knee gives way, or feels like it is going to give way, when it is active or stressed in a certain way
Diagnosis
Physical examination and medical history consultation
X-rays
MRI
Treatment
RICE (Rest, Immobilization, Compression, Elevation)
Non-steroidal Anti-Inflammatory medications
Physical therapy
Surgery
Source: http://www.nlm.nih.gov/medlineplus/ency/article/001079.htm