Anterior cruciate ligament, or ACL, injuries are amongst the most common type of injuries affecting today’s athletes. According to the Canadian Academy of Sport and Exercise Medicine, about 250,000 ACL injuries occur in the USA and Canada each year. ACL injuries are usually caused by either an impact or a sudden shift in position; according to the American Academy of Orthopedic Surgeons, 70 percent of ACL injuries in athletes happen through sudden movements, like pivoting, cutting, sidestepping, out of control play or awkward landings, while about 30 percent of ACL injuries occur from contact with other players.
For a severe ACL injury, surgery is usually required to restore the knee’s function and for the athlete to return to play. While one can function with a torn ACL in daily activities, it will prevent an athlete from performing at their previous level and is also a risk for other injuries.
The general goals of rehabilitating an injured ACL are as follows:
- Regain knee stability
- Improve muscle strength
- Improve function
- Decrease re-injury risk
In this stage of the injury, whether surgery is being considered or not, physiotherapy focuses on reducing inflammation and pain and regaining functional range of motion (ROM), strength, and knee stability.
In order to reduce swelling and inflammation, PRICE principles are followed: Protect, Rest, Ice, Compress and Elevate. Modalities such as ultrasound and interferential current (IFC) may also help reduce pain and swelling in the knee. In order to maintain stability and protect the knee at this stage, taping and/or bracing are used.
ROM exercises include simple flexion/extension movements of the knee to the tolerable range limited by pain, and gentle movements (such as slow kicks and cycling motions). Strengthening should focus on either isometric or closed kinetic chain for extension (straightening the knee) motions to avoid further injury to the ACL. These include straight leg raises and pushing the back of the knee down onto the bed with the knee straight. Strengthening knee flexion (bending of the knee) may be done with one lying on the tummy and bending the knee in that position.
Before the Surgery
Preparation for surgery is a stage that builds upon the acute stage protocols. These include continuing to reduce the pain and inflammation of the knee and progressing exercises that were initially introduced to continue improving range of motion and strength in the knee. One should gain the most function as possible before the surgery in order to speed up the recovery time. Prior to surgery, the knee should have little to no swelling, a full range of motion and a normal (or close to normal) gait pattern.
In this stage, mental preparation for the surgery is also enforced, including education on what to expect after the surgery and the recovery process. Strategies to help manage the immediate post-surgery phase, such as how to use crutches and how to go up and downstairs with them, are also introduced.
Different surgeons have different protocols as to how to progress exercises and load-bearing after surgery. The following is one of the protocols on the recovery process after surgery:
RICE principles are applied to reduce swelling and inflammation. Braces and crutches are mandatory at this stage. The goal of the first week is to achieve full extension and 70 degrees of flexion. Strengthening exercises for the quadriceps, hamstrings, and gastrocnemius (calf) muscles are also given.
With improving strength and range, progression in crutch usage occurs – first learning to use just one crutch. Strengthening exercises continues to focus on closed-kinetic chain and isometric exercises. A stationary bike is often used to help improve knee range of motion, with the goal of being able to complete one rotation (requires at least 90 degrees of knee flexion).
Progression of exercises continues based on how much pain and swelling is in the knee. At this stage, the usage of the knee brace is gradually reduced. Balance and proprioception exercises may begin if strength is good and pain is sufficiently reduced. More complex and intensive strengthening exercises may begin.
Dynamic exercises, such as backward and lateral movements are introduced. Isokinetic training, such as riding a stationary bike and walking on treadmills may begin in earnest.
Functional exercises such as running and jumping are introduced at 3 months. Work on agility, proprioception, and balance continue.
Month 4-5 and Beyond:
For return to full function to occur, one needs to continue improving knee endurance, and strengthen the knee stabilizers. Functional drills, some of which may be sports specific, may be introduced. These could include specific footwork techniques, sudden acceleration/deceleration drills and running and cutting maneuvers. Follow up visits with the physiotherapist should occur regularly in order to continue progressing the exercises until the athlete is at full function.
Contact one of our physiotherapists at Vansports Physio if you have any additional questions on how to recover from an ACL injury!
- Campbell et al. Canadian Academy of Sport and Exercise Medicine Position
Statement: Neuromuscular Training Programs Can Decrease Anterior Cruciate Ligament Injuries in Youth Soccer Players. Clin J Sport Med 2014;24:263–267
- Woo, S. et al. Biomechanics of Knee Ligaments. The American Journal of Sports Medicine 1999;27:533
- S. van Grinsven, R. E. H. van Cingel, C. J. M. Holla, C. J. M. van Loon. Evidence-based rehabilitation following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2010; 18:1128–1144