The Lateral Collateral Ligament (LCL) runs along the outside of the knee joint, connecting the femur to the fibula. It is responsible for stabilizing the outer knee and preventing the joint from bowing outward. LCL injuries are less frequent than MCL injuries and often occur due to a direct blow to the inner side of the knee.
Signs of an LCL injury are concentrated on the outer side of the knee joint.
LCL Sprain: You may experience localized tenderness and minor swelling on the outer knee. Pain typically increases when you try to fully straighten the leg or put stress on the outer joint.
LCL Rupture: A complete tear often results in a noticeable feeling of instability. The knee may feel like it is giving way or shifting outward. In some cases, a rupture can affect the nearby peroneal nerve, leading to numbness or weakness in the foot.
A clinical exam is vital to distinguish an LCL injury from other lateral knee issues like iliotibial band syndrome or meniscus tears.
Physical Exam
Imaging: While X-rays help rule out bone fractures, an MRI is the gold standard for visualizing soft tissue. An MRI is frequently used to confirm the severity of the tear and to check for damage to the posterolateral corner, a complex group of structures that work with the LCL.
Treatment depends on the grade of the injury and whether other structures in the knee are involved.
Most isolated LCL sprains respond well to conservative care.
Hinged Bracing: This protects the ligament from sideways stress while allowing for controlled movement during the healing process.
Functional Rehabilitation: Exercises focus on strengthening the lateral stabilizers of the hip and knee to reduce the load on the healing ligament.
Platelet rich plasma (PRP) injections can be considered
Complete ruptures are evaluated carefully for surgical needs. If the knee remains unstable or if multiple structures are torn, surgery is performed to reattach or replace the ligament using a tissue graft.