What do you know about the ACL ?

Ligament injuries to the knees are commonly found in athletes of all ages. The anterior cruciate ligament (ACL) is typically the structure most often injured by an excessive torsion of the knee. Alpine skiing is a sport that requires good strength and control in the legs, and unfortunately ACL injuries happen quite often with bad falls. What are the consequences of this type of injury? Is surgery always necessary, and is it still the best option?


What is a ligament?

Firstly, we must understand what ligaments are and what purpose they serve. A ligament is a strong but flexible band that connects 2 bones in a joint. Along with the joint capsule, it aids in stabilizing of the joint. Ligaments provide passive stability by limiting excessive movement in unwanted directions. However, the role of a ligament is not limited to passively ensuring the stability of a joint. There are several nerve endings inside our ligaments which are, in fact, receptors that tell our brain about the position of our joint in space; this is what is known as proprioception. The receptors send signals that travel through our nervous system to our brain, which then sends a command to the muscles around the joint to provide active stability and control in order to prevent excessive movement that could lead to injury.


The anterior cruciate ligament in more detail…  

The ACL, along with the posterior, medial, and lateral cruciate ligaments, connects the femur to the tibia. The role of the ACL specifically is to limit forward shearing of the tibia relative to the femur, and along with the posterior cruciate ligament, to limit excessive torsion of the knee. Injury to the ACL results in a decrease in passive stability of the knee and a decrease in proprioception. This type of injury occurs frequently during falls while skiing, where there can be excessive twisting at the knee, especially when the ski does not come off the boot as it should during a fall.


There are different grades of ligament injury (or sprain) depending on the severity: Grade 1 sprain represents elongation of the ligament fibers without a clear tearing; Grade 2 is a partial tear of the ligament; and Grade 3 is a complete tear. Grades 1 and 2 sprains are almost always managed with physiotherapy, and surgery is rarely an option if the involvement is limited to the anterior cruciate ligament only. For grade 3 patients (complete tear), physiotherapy intervention often allows excellent recovery of function and even a return to sports. In these cases, physiotherapy treatments are highly recommended in order to re-educate active control of the knee and strengthen the surrounding muscles.


What about surgery? 

In some cases, despite optimal rehabilitation after a complete tear of the ACL, significant instability persists and the knee may buckle unpredictably. In this case, surgery is considered as the next option. However, we know that the better the knee has healed before undergoing surgery, the easier the rehabilitation after surgery will be. It is therefore essential after an injury to the ACL to properly rehabilitate the patient’s mobility, strength and control of the knee, whether surgery is considered or not at that point in time.

Current scientific evidence shows us that physiotherapy intervention remains the treatment of choice for complete tears of the anterior cruciate ligament.

Injury prevention remains an important component for all skiers and athletes in general. Strengthening, balance, and proprioception exercises are strongly encouraged both during the preseason and the ski season itself. To find out more, consult your physiotherapist to make the most of your ski season!

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