Published on April 15, 2022

Image of a man holding an injured knee

ACL injuries: What you need to know

The anterior cruciate ligament, more commonly known as the ACL, is a ligament located in the center of the knee which connects the femur (thighbone) to the tibia (shinbone) and controls movements of the tibia. Without an ACL, you wouldn’t have a stable knee, which would cause uncontrollable movement of your lower leg. Your ACL is used in everyday activity, especially if you tend to be physically active in sports that require frequent and sudden deceleration.

It is more common than you would think to tear your ACL. According to the Centers for Disease Control and Prevention, ACL injuries affect as many as 250,000 Americans each year. Females tend to be more at risk than males because of their differences in strength, anatomy and genetics. Although ACL injuries may occur at any age, they most commonly affect 15 – 45 year olds due to their dedication to physical activity.

What causes an ACL injury?

Stephan Prô, MD, a sports medicine physician and orthopedic surgeon at OrthoKansas, said most ACL injuries occur with a pivoting or

Stephan Prô, MD

Stephan Prô, MD

twisting motion where the foot is planted and the body twists and turns a different way.

ACL injuries most commonly occur through sports and physical activities such as basketball, volleyball, soccer and football. In addition to pivoting and twisting motions, stopping movement suddenly, changing movement rapidly, or landing from a jump or collision incorrectly can all cause potential risk to your ACL.

“We see ACL injuries within all age groups,” said Dr. Prô. “The vast majority of ACL tears are associated with sports injuries including jumping, landing and twisting movements. There are also occasions when someone will injure their knee during everyday life activities such as a slipping on ice or falling from ladder, etc.”

How can you tell your ACL is injured?

Individuals with an ACL injury can face a variety of symptoms related to the tear. These include:

  • The sound of a popping noise while moving your knee
  • Discomfort while moving your knee
  • Pain and swelling in your knee area
  • Inability to move the knee as normal
  • Tenderness along the joint line

If you experience any of these symptoms, it is important to seek medical treatment before they worsen. Although most patients are immediately aware of their injuries, some are not. Dr. Prô shared that in his experience treating ACL injuries, he has seen both patients who want immediate medical attention, and others who have experienced a chronic history with an injured ACL.

“The majority of patients present to the clinic within a few days of an injury, but we also see patients who present weeks to months after their injury. The most common symptom that we see in the case of a chronic ACL tear is instability or overall lack of confidence in the knee. In either case, the diagnosis is made by a combination of clinical examination and MRI findings,” said Dr. Prô

Different types of ACL injuries

According to the American Academy of Orthopedic Surgeons, there are different levels of injuries when it comes to your ACL, otherwise known as “sprains.”

  • A Grade 1 sprain occurs when the ACL is only slightly stretched and is the mildest of ACL injuries
  • A Grade 2 sprain occurs when the ACL is stretched to the point where it becomes loose. This is known as a partial tear of the ligament.
  • A Grade 3 sprain occurs when the ACL is completely torn in half, causing instability in the knee. This is the most common of the three types of sprains.

The surgical journey with an ACL injury

There are two main options to treat your ACL injury, depending on which one better suits your lifestyle. The majority of patients want to remain active post-surgery, so in an effort to return to doing jumping and twisting sports, Dr. Prô would recommend undergoing surgery.

“About 95% of patients have surgery, but some opt for non-operational treatment which is always available for discussion,” he said.

The typical surgery for an ACL injury is done on an outpatient basis, meaning that the patient has surgery and returns home for recovery within the same day. The procedure, also called reconstruction, is done in order to return the ligament to its peak ability of function. If patients opt for non-operative treatment, it consists of aggressive physical therapy, bracing and activity modifications.

After the reconstruction is completed, patients leave the hospital on crutches and use them for approximately two to three weeks until they are comfortable without their aid. All post-reconstruction restrictions depend on the severity of the case and the type of injury that occurs. For example, some patients may be on crutches longer than others and some may undergo physical therapy longer than others. Your doctor will keep you on a recovery schedule that is best for your body. It takes approximately six to nine months for patients to fully recover and return to their full athletic ability. OrthoKansas uses objective measurements with strength, power and range of motion that will help guide an athlete’s return to play, as opposed to using a strictly time-based recovery date.


Typically, physical therapy begins within a week of the reconstruction. Physical therapy is broken down into phases, with each phase’s goal to accomplish a different level of achievement in rehabilitation.

Tyrel Reed, DPT, physical therapist with LMH Health Therapy Services, said that in the early stages of physical therapy, the patient will

Tyrel Reed, DPT

Tyrel Reed, DPT

come in two to three times per week to help re-establish their range of motion, normal walking mechanics, and basic strengthening.

“In the later stages, typically three months and on, we will decrease the frequency of sessions to one to two times per week, or even every other week,” Reed said. “During this stage, the patient will have a structured strength and conditioning program to help with the restoration of remaining deficits, in addition to their therapy sessions.”

Physical therapists at LMH Health work to help patients complete a full recovery. Reed shared how in the first month of physical therapy, physical therapists work to regain knee extension and improve quadriceps muscle activation in patients. After that is complete, they work to gradually restore knee flexion and range of motion while adding in more functional tasks such as walking, squatting and using stairs. Physical therapists continuously address remaining strength deficits in patients to promote a safe return to sport.

Preventative measures

Although the movements that cause an ACL injury occurrence are unpredictable, you can take some preventative measures to help prepare yourself.

“The best strategy to reduce the risk of a potential ACL injury is coordinated strength training with preventative exercises,” said Dr. Prô. “Multiple injury prevention programs are available, all focusing on improving landing mechanics, and balancing quadriceps or hamstring strength.”

Together, LMH Health and OrthoKansas provide the comprehensive and highly specialized orthopedic care you need to stay active and healthy. Turn to our experts for a consultation and treatment for your orthopedic health.

Shea Eckert is an intern with LMH Health Marketing & Communications.

ACL injuries: What you need to know

Media Inquiries

For media inquiries related to LMH Health contact:
Amy Northrop
Director of Communication
Phone: 785-505-2931