The anterior cruciate ligament (ACL) is part of a group of ligaments that stabilize the knee joint. This ligament runs through the center of the knee joint between the two bones that make up the knee–the femur (thigh bone) and the tibia (lower leg bone). The ACL’s primary role is to restrain anterior translation of the tibia on the femur but it aids in stabilizing against excess movement in other planes as well. When the ACL is torn, it compromises the stability of the knee. Most ACL injuries occur during athletics, however, a poorly executed everyday task can also result in an injury to this area. Because of the mechanics of the ACL, it is susceptible to tearing when excessive strain is placed across the knee. ACL tears can result from both contact and noncontact injuries. Some common ways that the ACL is injured are as follows:

• An athlete plants their foot in the grass while pivoting their upper body to change directions
• A basketball player lands after a jump and their knee suddenly hyperextends while the lower leg rotates inwards
• Someone missteps off a curb
• An athlete crashes into the knee of another athlete
• A skier takes a hard fall while attached to their skis

Symptoms of an injured ACL:

• An audible pop may be heard when the ligament tears
• Significant knee pain develops immediately after the injury
• Swelling develops within the first 24 hours and can persist for quite a while after the injury
• It may be difficult to straighten or bend the knee fully
• Tenderness around the knee is common
• A deep ache may be felt around the knee that worsens with activities like walking or climbing stairs

If you decide to work with a physical therapist to help with preparing for ACL surgery, your entire treatment plan could consist of around 8-20+ different ACL prehab physical therapy sessions that will each last 60-90 minutes. Once you complete your customized physical therapy treatment plan, you will be able to continue to do the prescribed stretches and exercises utilized during your PT sessions yet in the comfort of your own home.

PREHABILITATION FOR ACL RECONSTRUCTION SURGERY

For those who must undergo ACL reconstruction, there is often a period of waiting that occurs before the surgery is scheduled. Research has shown that undergoing a course of rehabilitation prior to surgery can help improve surgical outcomes. The goal of a prehabilitation program is to target modifiable factors associated with long term outcomes and to prepare the patient for the recovery process. Four targets of a prehabilitation program include:

• Knee range of motion
• Quadriceps strength
• Level of activity prior to surgery
• Patient education

• Trouble restoring full range of motion is one of the more common post surgical complications so establishing normal range of motion before the surgery is a way to help minimize this complication
• Swelling and joint effusion can inhibit muscle activation which make it difficult to restore normal strength and motor control to the knee for return to normal activity
• The use of ice, elevation and compression may be used to reduce swelling
• Modifying weight bearing to limit the inflammatory response may also be recommended early after the injury

Start a progressive exercise program: Goals in this second phase of early post-injury rehab for an ACL tear include maximizing muscle strength, specifically quadriceps muscle strength, and neuromuscular control. Reduction in joint swelling and restoration of range of motion are important precursors to progressing an exercise program and your PT will help monitor your response to exercise and progress the exercises accordingly.

• Having at least 90% return of quadriceps strength compared to the opposite side leading into ACL reconstruction is optimal
• Restoring neuromuscular control and coordination to the knee is helpful prior to surgery
• Exercises often start as “open chain” exercise in which your foot is held in the air while you work on strengthening the muscles of the hip and thigh
• Balance exercises like single leg balance can help restore neuromuscular control
• Perturbation training in which the patient stands on one or both knees and resists outside forces from multiple directions can also be beneficial
• Near the end of a good prehabilitation program, some patients will even perform heavy resistance training or plyometrics but this should only be undertaken with the guidance of a trained physical therapist