ACL Rehab for the Athlete: What Should it Look Like?

ACL Rehab for the Athlete: What Should it Look Like?

If you have suffered and ACL injury, you likely know that you have a long road ahead of you before you even think about playing sports again.  After an ACL reconstruction, you will need to undergo at least 9 months of rehab before returning to sport.  During these months you will go through many different stages of rehab each with a different primary focus.   According to an ACL Rehab Guide published in 2013, there are 5 phases of rehab:

1. Recovery from Surgery
2. Strength and Neuromuscular Control
3. Running, Agility, and Landings
4. Return to Sport
5. Prevention Re-injury

You will notice that there is no time frame on the phases. This is to limit progression for the sake of progression at different time points.  Time post surgery progression has the potential to shift focus off of the goals of our rehab as outlined in the various stages and onto time since surgery.  Time since surgery is very important with regards to graft healing and these guidelines need to be kept in mind when going through rehab but in rehab we need to focus on the goal of returning to sport and our rehab should be built around specific goals that will allow that goal to be met.

A rough time frame based on graft healing allows for safe return to:

• Jogging: 4-5 months
• Low-Level Agility: 5-6 months
• Jumping: 6-7 months
• Cutting: 7-8 months
• Return to Sport: 9 months

These time frames are not exact and should be compared with a criterion based progression as outlined below in order to safely and effectively return an athlete to sport.  Returning to these activities a couple of weeks early will likely not have any negative effects as long as there is appropriate strength and neuromuscular control.  Initiation of an activity any more than a few weeks early is not recommended even if proper strength and control are present.

Phase I: Recovery from Surgery

Goals for Phase 1 include: 

• Restoration of ROM and mobility
• Most important early is to regain full extension.  Keep moving the knee and flexion range of motion will gradually return but if extension is not regained within the first couple weeks it is very difficult to gain.
• Management of pain and edema.
• This can be performed with elevation, gentle motion, icing, and caution not to over-stress the injury by doing too much activity or inappropriate exercises.
• Initiation of strengthening with emphasis on the quadriceps.
• This can accomplished with some simple activation exercises and will likely be augmented in your physical therapy sessions using a special type of electrical stimulation that is designed to help improve your ability to recruit more muscle fibers each time you contract.
• The quadriceps muscle will experience far more atrophy and weakness after surgery than any other muscle and therefore will be the primary focus of early strengthening as well as strengthening throughout the course of rehab.
• Another potential intervention at this time is: blood flow restriction therapy.
• This is performed using pressure cuffs that decrease the amount of blood flow to the limb without compromising nerve function. This deprivation of oxygen allows for the recruitment of type 2 muscle fibers. Type 2 muscle fibers are historically very difficult to target during early rehab as they are primarily used for high force or high velocity exercise.

Phase 2: Strength and Neuromuscular Control

Goals of Phase 2 include:

• Normal / Symmetrical Gait Pattern
• This will normally come back as you regain ROM and confidence on your involved limb. 
• Walking in front of a mirror or taking videos every so often will help you better visualize if your gait looks significantly asymmetric.
• Regain Single Leg Balance
• Working on your balance will be performed in therapy, but it is important to practice at home as well. 
• Standing on one foot with a little bit of support at home is a good place to start. This can progress to balancing without support, then while on a couch cushion or pillow.  Eventually you can work on doing easy things around your house like brushing your teeth or making a sandwich while balancing on one foot.
• It is also good to practice with your eyes closed which makes your joint proprioceptors work on overdrive to accommodate for the loss of visual input.
• Regain Muscle Strength
• This is arguably the most important part of rehab as the number one predictor of re-injury after ACL surgery (ACL retear or other knee injury such as tendinopathy or patellofemoral pain) is quadriceps strength deficit.
• The goal during phase 2 will be to restore the quadriceps to 85% of your uninvolved side to indicate enough strength to theoretically handle the stresses involved with running and jumping which are added in phase 3.
• There are specific ranges of motion during exercises that do not place stress on the ACL and it is very important during the early stages to maintain these restrictions to allow the best possible healing of the surgical graft.
• Toward the end of this phase, restrictions on ROM are normally lifted and strengthening through a full range is allowed.
• As you progress through strengthening it is important to monitor both pain and swelling which should both be kept to a minimum throughout rehab.
• Be able to perform a Single Leg Squat with Good Technique and Alignment
• A single leg squat is a great way to assess if strength, neuromuscular control and balance have all progressed to a good enough level that, graft healing time frames aside, you can begin to progress to the next stage which includes running, an introduction to agility, and introduction to proper landing.

Arguably the most important part of rehab, and somewhere that physical therapists have historically fallen short when rehabbing the patient with an ACL reconstruction is the strengthening portion.  It is common for athletes to continue to have quadriceps strength deficits up to 2 years post injury.  If your leg is to get stronger your rehab eventually needs to feel like a strength and conditioning session.  Your muscles should get sore without an increase in your pain or swelling.  

If you are 3 - 4 months into your rehab and you have not yet felt quadriceps muscle soreness after a physical therapy session, it may be time to ask your physical therapist for a program that will push you harder to make sure that your leg is ready to go back to sport at 9 months and you don't have to miss a day more than is absolutely necessary.  

If your therapist continues to fail at providing you with a sufficient strengthening program, it may be wise to change physical therapists and find one that has experience with strength and conditioning or sport performance for the end stages of rehab.

Phase 3: Running, Agility, and Landings

Goals for Phase 3 include:

• Score 'excellent' on a jump rebound task.
• Phase 3 begins with working on simple landing tasks, then progresses to jumping and landing, then to jumping and rebounding.  Each of these places more demand on the musculature to control motion as well as the tendon which needs to gradually regain its tolerance to jumping type activities to avoid getting jumper's knee when going back to sport.
• A score of 'excellent' indicates that you have no compensatory patterns or significant 'movement faults' that may place you at slightly increased risk of re-injury if not addressed.
• Progress successfully through an agility program.
• Low level agility can be something as simple as low speed side shuffling or forward / backward jogging. Over time these activities will be progressed and will slowly begin to look like agility exercises that you would perform with your sport.
• Regain full strength and balance.
• Strength needs to be measured.  There are a few different ways to assess strength, but a leg press 1 RM and a knee extension peak force output are some of the most commonly used.
• One common balance assessment is the Y-balance test which involves a maximum reach in 3 directions.  The goal is to have a similar total reach distance as well as minimal differences between limbs in each direction.
• Other goals include:
• Single leg hop symmetry
• Single hop, triple hop, and timed 6 meter hop are common assessments.

Once phase 3 is completed you are nearing the end stage of your rehab. This will normally occur sometime near the 9 month mark.  Once you have met all of the goals for phase 3 you will progress to phase 4 which is the return to sport testing phase.

Phase 3 involves a lot of jumping, hopping, cutting, and agility exercises. It is nice to have some space to perform these exercises so I would recommend finding a physical therapy or sports medicine facility that has ample space to perform some of these style drills. A few hundred square feet of open space as well as at least 30 feet of straight line open space should suffice.

Phase 4: Return to Sport

Goals for Phase 4 include:

• No swelling, good graft stability, flexion and extension ROM equal to the uninvolved side.
• Subjective assessment called the "IKDC Subjective Knee Evaluation Form" score that is high enough to indicate that you are confident on your knee and feel comfortable returning to a high level of activity.
• Functional testing which includes some of the tests that were performed earlier in rehab as well as some additional tests aimed at assessing strength, endurance, neuromuscular control, balance, agility and power.
• In order to be cleared to return to sport you will need to pass all functional testing with no greater than a 5% deficit compared to your uninvolved limb.

Sometime early on in your rehab you should ask your physical therapist what their return to sport test looks like, and what criteria you will have to meet before you go back to sport.  If all they say is "hop testing" you can be confident that they haven't put a lot of thought into what you will really need to be able to perform to go back to sport.  If your therapist does not have a criterion based progression that they follow, the one used for much of the information in this blog post can be accessed here.

Phase 5: Prevention of Re-Injury

The goal for phase 5 is to be placed on a comprehensive program that targets strengthening, balance, and plyometric activities that are targeted at re-injury prevention.  This program should be performed 2-3x / week for at least 6 weeks after passing return to sport testing.

Conclusion:

Recovery from an ACL injury is a long process. It is very important that you meet the goals of each phase along the way, stay patient and trust the process.  Don't be afraid to advocate for yourself if you feel that you can do more in rehab, there are safe ways to strengthen early after surgery and your rehab should eventually feel like a tough workout.  It takes consistent work over a long period of time but if you stick with it you will come out an even better athlete than before your injury.   

Hopefully this information provides a rough idea of how rehab should look and gives you a few things to look for when finding a physical therapist.

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Citation

Cooper, R. (2013). ACL Rehabilitation Guide.