There are four main ligaments in the knee that contribute to the stability of the knee.
The Anterior Cruiciate Ligament (ACL)
The ACL (anterior cruciate ligament) is one of 4 ligaments of the knee and helps with not only knee movement, but protection. An ACL injury is very common in athletes who participate in sports such as football, basketball, soccer and rugby, though ACL injuries can also occur in older individuals due to a slip and fall incident.
The ACL can be damaged during direct impact to the front of the leg, when it is not in movement. When this happens, there may be a sudden popping sound, pain and swelling around the knee. A knee brace may be recommended to protect the knee, as well as Physiotherapy. Depending on the severity of the injury, surgery may be needed to repair or replace the torn ligament. Rehabilitation will be needed after surgery takes place. Early treatment will include pain management and addressing any swelling. As it progresses into the 3rd and 4th weeks, the focus will shift towards exercises such as riding a stationary bike to help the knee bend to 100°. During later weeks, the exercises will become more challenging, ambulation and balancing exercises. Physiotherapy will continue until balance and mobility become strong.
The Posterior Cruciate Ligament (PCL)
prevents the knee from translating backward. A tear of the PCL is less common than an ACL tear. Commonly, a PCL tear can occur with excessive hyperextension of the knee or twisting of the knee.
The Medial Collateral Ligament (MCL)
is located on the inside of the knee joint and prevents the knee from excessive side to side movements. The MCL sprain or tear can occur with an ACL and medial meniscus tear with high impact blows or twisting of the knee.
The Lateral Collateral Ligament (LCL)
is located on the outside of the knee joint and also prevents the knee from excessive side to side movements.