27/08/2026
🦵 Ligaments of the Knee: What Do They Do?
Your knee relies on four main ligaments to provide stability, control movement and protect the joint during everyday activities and sport. 💪🏃♀️
🔹 1. ACL – Anterior Cruciate Ligament
Located inside the knee joint, the ACL is one of the main stabilisers of the knee.
Its main functions include:
➡️ Preventing the shin bone (tibia) from moving too far forward relative to the thigh bone (femur)
➡️ Helping control rotation and twisting
➡️ Providing stability during running, jumping, landing and changing direction
⚠️ ACL injuries are particularly common in sports involving sudden changes of direction, pivoting or awkward landings.
🔹 2. PCL – Posterior Cruciate Ligament
The PCL works alongside the ACL to maintain knee stability.
Its main functions include:
➡️ Preventing the tibia from moving too far backwards relative to the femur
➡️ Maintaining overall knee stability
➡️ Supporting the knee during bending and weight-bearing activities
💥 PCL injuries can occur when a strong force pushes the shin backwards, such as a direct impact to the front of a bent knee.
🔹 3. MCL – Medial Collateral Ligament
The MCL runs along the inner side of the knee.
Its main functions include:
➡️ Providing stability to the inner knee
➡️ Resisting excessive inward movement
➡️ Helping protect the joint during side-to-side movements
🏃♂️ MCL injuries commonly occur when a force is applied to the outside of the knee, pushing it inward.
🔹 4. LCL – Lateral Collateral Ligament
The LCL runs along the outer side of the knee.
Its main functions include:
➡️ Providing stability to the outer knee
➡️ Resisting excessive outward movement
➡️ Helping control side-to-side stability during movement
⚠️ LCL injuries are less common but may occur following a force to the inside of the knee.
🦵 Why Are Knee Ligaments Important?
Together, the ACL, PCL, MCL and LCL keep the knee stable while allowing controlled movement.
Healthy knee ligaments are important for:
🚶 Walking
🏃 Running
🦘 Jumping
🛬 Landing
🔄 Pivoting
↔️ Changing direction
🏆 Sport
🚨 Experiencing knee pain or instability?
Pain, swelling, giving way or difficulty returning to activity following a knee injury may indicate that the joint requires further assessment.
👩⚕️ A physiotherapy assessment can help identify the structures involved and guide appropriate rehabilitation, strengthening and return to activity.
📩 If you're struggling with knee pain or instability, don't ignore it.
