This was a statement from a young athlete that wanted to put off an ACL reconstruction after a grade 3 ACL sprain (aka tear). She wanted to play basketball in her senior year of high school. If she had surgery, she would miss the season. Her swelling had already decreased and she had good knee motion. It was now time to start activating the muscles around her hip and knee to help stabilize the knee. She did very well in therapy and did return to basketball for her senior year. I did not see her after she was discharged from physical therapy but I assume that she eventually did have surgery. However, surgery is not always required. Read on to learn more about ACL sprains. We will start with anatomy!
The knee joint
The knee is the largest joint in the body. It is made up primarily by the tibiofemoral joint and patellofemoral joint. The tibiofemoral joint is what most of us think of as the knee. It is the joint made between the bottom of the femur (the thigh bone) and the top of the tibia (the larger lower leg bone). The patellofemoral joint is the joint made between the femur and the patella (the kneecap).
What are ligaments?
Every joint has ligaments. Their function is to control excessive motion of the joint. They are also a source of proprioception. Proprioception is knowing where you are in space. For the knee, this means that you would be able to determine the position of the knee without having to look at it. Ligaments are primarily made of collagen fibers and have very little elasticity. They are meant to add stability and are not flexible. You cannot stretch a ligament without damaging it.
What is the ACL?
The anterior cruciate ligament or ACL is located inside the knee joint. The ACL runs from the end of the femur (the thigh bone) to the top of the tibia (the shin bone). Its primary function is to prevent the tibia from sliding forward on the the femur. It also assists in limiting rotation of the tibia.
What is a sprain? Is it different than a strain?
A sprain is a tear or injury to a ligament. Whereas a strain is a tear or injury to a muscle or tendon. When the ACL is injured, it is considered a sprain because the ACL is a ligament of the knee.
How does the ACL get injured?
An ACL tear is a knee injury that commonly occurs with athletes. However, non-athletes can also suffer from ACL injuries. Women are more likely to tear their ACL than men. There are two main categories of injuries:
- Direct contact
- This accounts for about 30% of all ACL injuries.
- This occurs with a direct blow to the knee.
- The most at risk for direct contact injury are football players.
- Non-contact
- This accounts for about 70% of all ACL injuries.
- Can occur with
- Sudden changes in direction while foot is planted
- Rapid stopping while running
- Jumping and landing abnormally
- The most most at risk for non-contact injury are skiers, soccer players, and basketball players
What are the symptoms of an ACL tear?
There are several symptoms associated with an ACL tear. These include:
- A loud “pop” or snap that might be heard at the time of injury.
- Feeling of instability in the knee
- May give way with pivoting and twisting
- Extensive swelling in the knee
- Knee pain
- Difficulty straightening the knee
- Difficulty walking or putting weight on the affected leg
How bad is the tear?
As with all sprains, there are grades to the severity of the injury. These grades include:
- Grade 1: This is the mildest strain. The ligament fibers are stretched but not torn. Walking will, most likely, not be affected. Some swelling tenderness to the touch but no instability.
- Grade 2: This is a partial tear of the ACL, but it is not a complete tear. There is more pain and swelling in the knee. Walking will be affected and there will be some feelings of knee instability. The knee might give out during activity.
- Grade 3: This is a complete tear. There will be significant swelling and pain in the knee. The person will typically have difficulty bending the knee. Crutches will be needed to aid in walking. There will be significant knee instability.
Special considerations
The ACL is usually not injured in isolation. These tears often occur with other injuries to the knee. The “unhappy triad” is concomitant injuries to the medial collateral ligament (MCL), ACL, and the medial meniscus. These three tend to sustain injuries together. However, the lateral collateral ligament (LCL), lateral meniscus, and posterior cruciate ligament (PCL) could also be involved. Bruising or fracture to the underlying bone might also occur with an ACL injury. All of these structures will need to be tested by the physician or physical therapist to rule out injury.
Will I need surgery?
The answer is maybe. Grade 1 and most grade 2 sprains can recover with physical therapy. The ACL will not heal on its own because it has no blood supply. This means that the knee instability that occurs after a grade 3 sprain or even a bad grade 2 will not go away on its own. However that does not necessarily mean that one needs surgery. Those with significant knee instability fall into 3 categories
- Copers – These are individuals who are able to return to pre-injury activity or sport without knee instability and without surgery. They are able to dynamically stabilize their knee through muscle activation.
- Noncopers – These are individuals who are unable to return to pre-injury activity or sport because of knee instability. They are unable to dynamically stabilize the knee. The people in this group will most likely end having surgery in order to obtain knee stabilization.
- Adapters – These are individuals who avoid having episodes of instability by changing their activities. For instance, a person might start jogging instead of playing basketball. This group makes up the majority of those that choose not to have surgery.
If the person is not an athlete, and is only mildly active then surgery is probably not necessary. Most athletes and active individuals choose surgery in order to return to their sport or activity without knee instability. However surgery is not always needed even for a high level athlete.
Who should I see?
- Physical therapist – A physical therapist is going to be an integral part of the healing process. Whether or not the person decides to have surgery, they will need physical therapy. Physical therapists can aid in decreasing pain and swelling, increasing strength and flexibility, and returning to sport safely. It is important to have a physical therapist assist in determining when the person is appropriate to return to sport and provide direction in how to prevent the injury from reoccurring.
- Orthopedist – An orthopedist is also going to be needed. Imaging would be required to confirm the extent of the injury, especially, if a grade 3 tear is suspected or other structures are involved. The orthopedist would discuss options including surgical reconstruction of the ACL.
What can I do at home?
There are many things you can do at home to aid in your recovery. These include:
- Relative rest – It is important to prevent further injury to the knee while you are recovering. If you are having pain with walking or bearing weight on the affected leg, then use crutches to help. If you are able to bear weight through the leg but are still unable to return to your sport, then practice relative rest. This means that you perform an alternate activity that will not affect the injury. For example, biking or swimming while you are unable to participate in your sport is an excellent way to maintain cardiovascular levels and strength. Having equal strength in both legs and no instability in the knee is required before returning to sport or activity.
- Ice – This is very important right after the injury. Ice the knee with an ice pack several times a day right after the injury especially if there is a lot of swelling. Elevate the knee above the level of the heart while icing to decrease the swelling. This can be done by lying on a couch and propping the leg up on a few pillows. Ice for about 20 minutes. Place a thin barrier, like a pillowcase, between your skin and the ice pack. You can continue to ice even after the initial injury especially if there is still pain and swelling.
- Range of motion exercises – These are very important to perform after the initial injury. They are very simple exercises designed to increase mobility of the knee while preventing the knee from getting overly stiff while recovering. They should be performed several times a day during the initial recovery. See the video below for some range of motion exercises for the knee.
- Flexibility exercises – These exercises are focused mainly on stretching the hip flexors, quadriceps, hamstrings, and the calf muscles. These muscles surround the knee and will tighten up when there is an injury to the knee. Improving the flexibility of these muscles will aid in the mobility of the knee. See the video below for instructions on how to stretch these muscles. You will need a stretch strap, dog leash, yoga strap, or something similar.
- Strengthening exercises – There are a couple different phases of strengthening when rehabbing from an ACL tear. These include weight bearing and non-weight bearing exercises. Weight bearing refers to putting weight through the joint. Examples of weight bearing include standing, running, walking – basically anything performed when standing on your feet. Non-weight bearing exercises are to be performed first to start strengthening the muscles with no impact through the knee joint. Once the swelling has decreased, normal knee motion is regained, and the person can walk/stand with little discomfort, then it is time to progress to weight bearing exercises. All of these exercises will focus on strengthening muscles around the knee and hip, especially the quadriceps. The quadriceps is the large muscle in the front of the thigh. When there is an injury to the knee it tends to shut down. This can lead to the feeling of the knee giving out. It is important to turn that muscle back on asap. Using resistance bands or ankle weights can add resistance and strength. See the video below for weight bearing and non-weight bearing exercises.
- Bracing
- A brace can provide feelings of support and increase stability when returning to previous sports or recreational activities.
- A knee sleeve can be helpful in decreasing pain and swelling when returning to activity.
In review
- The anterior cruciate ligament or ACL is located inside the knee joint.
- Its primary function is to prevent the tibia from sliding forward on the the femur.
- It also assists in limiting rotation of the tibia.
- An ACL tear is a very common knee injury that commonly occurs with athletes.
- Women are more at risk for injury than men.
- Noncontact injuries are more common than contact.
- Symptoms of an ACL tear include pain, swelling, and possible knee instability.
- There are grades of injury, with grade 1 being mild and grade 3 being a complete tear.
- ACL tears commonly occur with other injuries to the knee.
- Surgery would be needed if the person is unable to stabilize the knee after a large or complete tear of the ACL.
- There are things that you can do at home:
- Relative rest
- Ice
- Range of motion exercises
- Stretching
- Strengthening
- Bracing
As always, If you have questions about the content of this post or any other musculoskeletal questions, please e-mail me.
Further resources:
https://www.physio-pedia.com/Anterior_Cruciate_Ligament_(ACL)_Injury
https://www.physio-pedia.com/Anterior_Cruciate_Ligament_(ACL)_Rehabilitation
https://www.ncbi.nlm.nih.gov/books/NBK499848/
https://www.medbridge.com/blog/2018/02/management-acl-rupture-possible-paradigm-shift/