The knee joint is a hinge joint that forms the junction between the upper leg (femur) and the lower leg (tibia and fibula) with the kneecap (patella) sitting at the front. It is a large weight bearing joint which requires a number of strong rope like ligaments to stabilise the joint and to keep the bones in place during movement.
There are two main types of ligament found in the knee joint. The collateral ligaments are located on both sides of the knee and prevent the bones moving from side to side over each other. These are on the outer side (lateral ligament) of the knee which prevents bow legged deformity and the ligament on the inner side (medial ligament) which prevents knocked-knee deformity. The cruciate ligaments are found within the middle of the knee joint. The cruciate ligaments cross over each other in an “X” formation and they prevent the bones sliding backwards and forwards over each other or rotating sideways. The anterior cruciate ligament prevents the lower leg sliding abnormally forwards in relation to the thighbone while the posterior cruciate ligament prevents the lower leg sliding abnormally backwards.
As the name suggests a multi-ligamentous knee injury is one where more than one ligament in the knee is damaged: either of the collateral, or side, ligaments or either of the cruciate, or central ligaments. Multi-ligamentous knee injures can involve damage to two or three of the ligaments or even uncommonly all four ligaments. They often are associated with damage to other structures in the knee including bones, cartilage and tendons.
These are usually caused by high energy accidents or injuries, such as car or motorbike accidents. High levels of forces placed through the knee either twisting or bending can multiple ligaments to be damaged.
- Car accidents
- Motorbike accidents
- Skiing accidents
- Falls from large heights
- High energy collisions during sports such as tackling during football
A popping sound is often heard when knee ligament injuries occur. It is common to be unable to weight bear on the injured leg and the knee feels unstable. Due to the high energy nature of these accidents it is common for them to be associated with other injuries to the knee or other body parts. Importantly it can be associated to damage to the nerves and blood vessels in the leg resulting in numbness or weakness of the leg or even loss of the foot pulses which requires urgent medial attention. Other symptoms include:
- Swelling – the knee will begin to swell within 24 hours of the injury
- Limited range of movement
- Localised tenderness
Your doctor will ask you questions about the injury and your symptoms. Your doctor will do a clinical examination of your knee to assess the structures in your knee joint and the nerve and vessels of your leg. Your doctor will refer you for an x-ray to look for any fractures and also an MRI (magnetic resonance imaging) scan to assess the ligaments and other soft tissues such as tendons or cartilage. If vessel damage is suspected sometimes further scans specifically looking at the arteries are required.
This is a text block. Click the edit button to change this text. Immediate treatment of these injuries includes:
- Apply ice – ice packs should be applied to the knee in 20-minute intervals. Ice should not be applied directly to the skin.
- Compression – apply a supportive bandage to help with the swelling
- Elevate the affected leg
- The knee should be placed into a brace and weight bearing should be avoided
- Due to the potential risk of damage to nerves and vessels immediate medical assessment should be sought
Due to the high risk of ongoing instability of the knee these injuries are rarely treated non-operatively unless the patient is too medically unwell to undergo surgery. Sometimes patients who are very low demand may also be managed without surgery.
Tearing of the ligaments often requires them being either repaired or reconstructed. Ligament reconstruction is a procedure where a graft material, usually a tendon from around the knee, is fixed in place of the ruptured ligament. This can usually be done as a minimally invasive or arthroscopic procedure. It is important to follow your surgeons post-operative instructions as rehabilitation will be required after this procedure.