Anterior Cruciate Ligament (ACL) Injury of the Knee

What is the ACL?

ACL stands for Anterior Cruciate Ligament of the knee. The knee is the largest and one of the most complex joint in your body. It relies on four ligaments and other muscles and tendons to function properly.

There are two ligaments either side of the knee: the Medial Collateral Ligament (MCL) and the Lateral Collateral Ligament (LCL). There are also two crossed ligaments in the center of the knee, the Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL). The ACL connects the front part of the shin bone (tibia) to the back part of the thigh bone (femur) and keeps the thigh bone from sliding forward. It also helps stabilize the knee in pivoting activities.

How does an ACL Injury occur?

One of the common ways for the ACL to be injured is by a direct blow to the knee, which commonly happens in football, netball or a fall when skiing. In this case, the knee is forced into an abnormal position that results in the tearing of one or more knee ligaments. However, most ACL tears actually happen without contact between the knee and another object. Such non-contact injuries happen when the child is planting the foot and cutting, landing on a straight leg, or making an abrupt stop. These movements are common in basketball, football, volleyball and soccer.

How do you know when you have torn your ACL?

In many cases, when the ACL is torn, you will feel the knee give way with an audible "pop." The injury is usually associated with a moderate amount of pain and continued activity is usually not possible. Over the next several hours, the knee becomes very swollen and walking becomes difficult. The swelling and pain usually are the worst for the first two days and then begin to subside. Sometimes there is no swelling at all, as the lining of the knee joint is also torn and the fluid leaks out of the knee.

What tests do I need to do to diagnose an ACL tear?

ACL tears usually cause enough discomfort to cause the injured person to seek medical attention. Dr Balakumar will examine the knee, and, in most cases, be able to identify which ligaments are injured. However, there may also be injuries to the joint surface that are more difficult to diagnose. In addition, swelling may sometimes make it difficult to diagnose a tear. Further evaluation with an MRI or arthroscope may be necessary to completely evaluate the injury.

Will I Need Surgery?

The most frequently asked question after an ACL injury is, will I need surgery? The answer varies from person to person. Many factors must be considered by the patient and Dr Balakumar when determining the need for surgery. The type of surgery also depends on whether the child has open growth plates or not. Most children who are very young are at risk of further injuring their knee from the ACL injury.

The two options for management are non surgical or surgical. The surgical management is aimed at respecting the remaining growth of the child and the possible growth plate damage from conventional adult type ACL surgery.

There is growth plate sparing options available for ACL reconstruction for very young children. In the adolescent, injury to the growth plate can be avoided by using long tunnels for the reconstruction with screws outside the growth plate. And for those whose growth plate closes, they will be treated as adults.