One of the most common injuries of the knee involves ACL injuries. Your ACL (anterior cruciate ligament), along with many other ligaments, provides stability to your knee. When the ACL is injured or torn, you may feel instability in the knee. This post will look into the anatomy of the knee, different treatment options, and what to expect during treatment with physical therapy to help you return back to sport after ACL injury.
**This is not medical advice. Please consult your medical provider for more information.
Anatomy
Your knee is composed of four bones and two main joints. The four bones are the tibia (shin bone), fibula (next to the shin bone), femur (thigh bone), and patella (kneecap). The two main joints of the knee are the tibiofemoral joint and patellofemoral joint. The joints are the spaces between two bones and the bones are held together by ligaments. The ligaments are what give innate stability to the knee.
Collateral Ligaments
The collateral ligaments are the ligaments on the inside and outside of the knee. They connect the femur to the tibia and fibula.
Medial Collateral Ligament (MCL)
The MCL is on the inside of the knee. It attaches onto the femur and tibia providing stability to the inside of the knee.
Lateral Collateral Ligament (LCL)
The LCL is on the outside of the knee connecting the femur to the fibula. It is the main stabilizer of the outer portion of the knee.
Cruciate Ligaments
Anterior Cruciate Ligament (ACL)
The ACL is a thick ligament that is found deep within the knee joint. It attaches diagonally onto the femur and tibia. It helps prevent rotational movements of the knee as well as preventing the tibia from sliding forward on the femur.
POSTERIOR CRUCIATE LIGAMENT (PCL)
The PCL is also found deep in the knee joint and it helps stabilize the knee by preventing the tibia from sliding backwards on the femur.
Causes
While ACL injuries can come from contact, 70% of ACL injuries are non-contact injuries. Females are at a much higher risk than males with the highest risk at around 16-17 years of age.
The role of the ACL is to prevent hyperextension and the tibia moving forward on the femur as well as limiting rotational movements through the knee. Contact injuries usually occur from a valgus force or being hit on the outside of the knee. This causes forceful stress to the inside of the knee. Non-contact injuries are typically closed-chain injuries meaning that the foot is planted on the ground at the time of injury. This will usually happen during deceleration with a rotational force towards the inside of the knee. This type of injury is most commonly seen with poor landing mechanics, pivoting, cutting, and quick deceleration.
Symptoms
Swelling is common shortly after injury to the ACL. It is also common to lose range of motion and feel pain in the knee and when touching around the joint line. While it is still possible to walk with a tear, you may feel discomfort due to less ACL stability. The inherent structure of the ACL is compromised with a tear which reduces the natural stability it provides to the knee.
Examination
While there are quick tests to check the stability of the knee and the integrity of the anterior cruciate ligament, an MRI is needed to confirm an ACL tear. There are many other injuries that can occur to the knee so it is important to speak with your doctor to confirm if the ACL is in fact involved in the injury.
Treatment
Speaking with your doctor will help determine the best course of action for you. Determining if a conservative or non-conservative approach is best will be based on age, significance of injury, activity level, and prior level of function. Younger individuals who participate in sports will most likely go through surgery to repair a torn ACL. However, an older individual with a more quiet lifestyle may be able to get away with conservative treatment alone.
Non-Conservative Approach
Individuals undergoing ACL reconstruction surgery are more likely to be younger and participate in sports. After surgery, physical therapy typically lasts 6-9 months depending on the level of activity the individual is trying to get back to. Sports and activities with higher levels of impact will take longer to complete physical therapy to ensure proper ACL stability and recovery. Read this article to learn more about surgical treatment and rehabilitation following surgery.
Conservative approach
For individuals living a more sedentary lifestyle or older individuals where surgery is not an option, a conservative approach with physical therapy may be a better option post ACL injury. Stability of the knee is the main focus with conservative treatment as the inherent stability of the ACL is no longer present and/or weak.
In order to provide better stability for the knee, it is important to strengthen the muscles that help prevent medial collapse of the knee (aka the glutes)! The course of PT treatment after an ACL injury focuses on quad and glute strengthening to provide the knee with greater stability.
