An ACL tear is one of the most common, serious injuries high intensity sport athletes suffer. There are over 200,000 cases a year, all of which require a lengthy rehabilitation process from surgery to being able to return to sports. In surgery, the doctor will fashion a new ACL from other soft tissue in the body, usually hamstring tendon or patellar tendon, making a graft. There are many return to activity and sport ACL protocols in existence and most of them are similar. However, there can be slight differences in each one of them making certain protocols more effective for the individual patient. These days, due to advancement in medicine, ACL surgeries are about 90% effective in allowing high performing athletes to return to sport. While this sounds positive, there are still many cases in which the patient either re-injures the same knee or does the same damage to the other knee. There are many contributing factors. A lot of times, patients suffer from graft failure which is caused by numerous things throughout the rehabilitation process. Every case is unique which makes developing a standardized ACL protocol difficult, however it is worth exploring the question: How does a patient recover properly from an ACL reconstruction? 

It begins with the mental aspect of this injury. Sometimes even harder than going through the physical rehabilitation of this injury, is hurdling the mental aspect of this injury. Athletes can usually make it through the rigors of physical therapy fine. What many athletes who have had this injury will say is that the psychological recovery is tougher. For people who spend their whole life active can have trouble dealing with being out of exercise and activity for an extended period of time. It also becomes difficult for athletes to throw themselves back into action. It can be hard for an athlete to go into the same risky movements they partook in before the injury occurred out of fear of re-injury. Many athletes are now beginning to seek help for this part of the recovery. This injury is emotionally draining, especially in the early stages. The emotional aspect of this injury is a major factor in delaying a return to sports as well as inhibiting the athlete from reaching the levels they were performing at prior to the injury. According to an article on sir.ca “Often Overlooked - The Psychological Impact of an ACL Injury” the main most common reasons are for reluctance to return to sport are: Fear of re-injury, decreased confidence, stress and anxiety regarding their physical condition, and feelings of depression. This source is written by a group of three doctors who use case studies with their own, professional opinions to make their conclusions. They value a wholistic approach to rehabilitation from ligament reconstruction. This is why it is important all athletes seek some sort of mental help while recovering and after recovering from ACL surgery. It is vital for athletes to keep confidence in themselves and their condition when returning to competition. No matter who it is, they will encounter mental problems. Professional football player Joe Flacco in an article with NFL.com, admitted the mental hurdle was the “toughest part” of his recovery from an ACL tear in week 11 of the 2015 season. While developing the mental fortitude is important when returning to sports, the physical development is a lengthy and challenging part of the recovery that takes the front seat for the better part of nine months.

The physical process to return to sport starts almost immediately after surgery. This phase of the rehab is known as the maximum protection phase or phase I, and lasts for 2-twelve weeks after surgery. In this phase, it is a goal of the patient to reduce the swelling in the knee and achieve extension equal to the unaffected side. Most surgeons will have you start physical therapy one to seven days following surgery. Some doctors believe having a full week of immobilization of the knee post surgery is more important than starting therapy a couple days after surgery. In the article “Return to Sports After ACL Surgery: 5 Professional Opinions,” Scott Slattery, MD, an orthopedic surgeon specializes in orthopedic sports medicine states “A short period of post-op immobilization leads to better quality biologic tendon to bone attachment.  In addition, this has helped me encourage patients to achieve early post-op full extension of the knee, which is very important.” He mentions studies done on animals to support this claim. Essentially, this idea to have the knee completely stabilized allows the graft to begin a much stronger relationship to the rest of the knee and body which will decrease the possibility of graft failure. In addition, having the knee completely extended for this period of time increases probability of regaining full extension which is widely accepted as one of the most important establishments when recovering from this injury. This is a practice that should be done if the patient is under no time constraints to return to activity. If the patient is under pressure to return in x amount of months, then this practice should not be done because the early phases of rehab will need to be done more aggressively. Having full extension allows the patient to walk properly and have full functionality of the joint. In addition, the patient should begin range of motion exercises and attempt to achieve ninety degrees of flexion within two weeks of surgery. As stated before, range of motion is a vital aspect when rehabilitating a torn ACL. This can be attained through various exercises including wall slides, patellar mobilizations, passive assisted knee flexion, seated knee flexion, and heel slides, both active and passive. During this phase, there are also exercises that need to be done in order to gain certain amounts of strength back. The patient must gain the ability to flex the quadricep muscles, known as quad sets. This will develop the basic muscles in the quadricep prior to beginning the main strengthening phases of rehab. Other exercises include straight leg lifts, weight shifting exercises, and double leg mini squats. The goals in this phase usually take 2-4 weeks to achieve. 

Between weeks 2 and 6 after surgery, phase II will take place. The goals of this phase according to UW Sports Medicine’s ACL Protocol are to restore proprioception, or proper body alignments like being able to walk and stand properly without assistance, build lower extremity strength, and achieve range of motion equal to the unaffected leg. During this phase, an important aspect of healing will occur in the form of revascularization. This is where blood and other healing agents return to the affected area of the knee. This stage in recovery is when the graft is at its weakest point and thus it is important to protect and nourish the new ACL. It is important to limit the activity and the strain on the ligament during this phase. Some believe in continuing on a regular basis during this stage, but it is an increased risk and a point where graft health should be prioritized over quad, hamstring, and calf strength. In order to achieve the goals of this phase, the inured person will graduate the exercises from phase I in order to accrue more strength in the affected leg. Much of the exercises in phase II are a continuum from the exercises in phase I, but there are some extra ones as well. All of the range of motion actions will continue into the second phase in order to develop the flexibility fully. Walking drills will be introduced and consist of high knee walking, both forward and back, walking in a zig zag, walking in hurdler motion, both forward and backward, and side stepping in the mini squat position from phase I. Another important aspect of this point in the process is developing good balance. Standing on one foot is the most basic action but as the balance skills become more advanced, the patient can perform other exercises that require greater concentration and balance. Balance exercises are vital in the return to sport process. They teach the athlete how to control his/her body again which will pay great dividends when finally back in the rigors of sport. Being able to stay on your feet and control the body will go a long way in the prevention process of the same injury in either leg. The goals in phase II will typically take 3-5 weeks to complete. 

Upon completion of the second phase of rehab, the patient will enter into the third phase where the patient will begin to seriously intensify the strengthening of the involved leg. At this point, approximately 8 to twelve weeks post operation, the graft will be strong enough to increase the work load on the affected leg. The goals in this phase are to continue pain-free strengthening of the involved leg at an increased rate, develop eccentric muscular control, develop proper alignment for activities of increased speed like running and jumping, and complete range of motion is expected. In order to make a quicker return to activity after an ACL injury, it is important to increase the volume of the weight training during this phase. In a fast progression, it is important to lift weights on the almost every day as long as there is no pain. However, this is not necessary and arguably ineffective when making valuable gains. It is more important to make sure the muscles recuperate which leads to more mass gained in each workout. Leg press, leg extension, eccentric leg press, hamstring curls, and calf raises are the most important lifts to do on the involved leg. All of them isolate the important muscles for protecting the ACL. Eccentric work is important for returning to sports since it will serve as a controlled simulation of impact. According to UW Sports Medicine’s ACL Protocol, the athlete should be pain free, have no swelling, and be able to perform a single leg squat forty-five to sixty degrees with proper posture in order to begin more activities involving landing from heights. At this point in the rehab, it is also possible to begin agility work assuming the patient has met the proper criteria as stated above. Should the athlete want to make a return quicker than 8 months, landings, agility, and extensive weight training should be emphasized. In a more conservative approach, the weight training should still be stressed, but the agility and landing components can be held off until a greater amount of strength develops on the involved extremity. Some of the exercises to develop muscle include, basic squat, squat and reach, full weighted lunge, weighted step up and step down, lateral step ups, and the other above listed weight lifts. Programs to develop the strength and mechanics needed for proper impact and landing consist of bounding, single leg hops, jump stops, and other plyometric programs. Balance should be another point of emphasis in phase III as the ability to balance provides stability to the whole body which obviously includes the lower extremities and the knee. Phase III takes many weeks to complete and will not be completed until a satisfactory clinical exam is had. The clinical exam will then clear the patient for the final phase of rehabilitation. 

The final phase, or phase IV, is the return to sport phase where much of the rehab will become sport specific in addition to continuing the strengthening of the affected extremity. This phase will typically begin anywhere from sixteen weeks, in cases where the athlete is making a rapid return, to twenty-four weeks in a more realistic case. The final phase of rehab should be pain-free and sport specific at a high intensity in order to most accurately simulate the rigors involved in a type I sport. Surgeons will have differing opinions on when it is possible to fully play sports again. Slattery says “Time questions aside,  I don’t allow return to Level I sport (soccer, basketball, football) until there is no pain with activity, no swelling, full range of motion, good stability, strength close to equal to the opposite side.  Then the patient has to pass a series of rigorous functional tests of neuromuscular control, administered by the physical therapist”

 (Return to Sports After ACL Surgery: 5 Professional Opinions). These tests include functionality tests such as range of motion equal to the uninvolved leg. There are also a series of jumping exercises where the patient needs to exemplify proper eccentric control of the leg and proper landing mechanics. These tests might be completed with hurdles and boxes and involve landing on both feet, or the just the effected leg. From sport to sport, the functionality and muscular control tests will vary slightly due to sport specific situations, but for the most part, they similar. This could be a reason why re-injury occurs. There should be a sport specific protocol for all sports. According to Slattery, it would not be safe for the athlete to return unless he/she has been able to complete tests that create an environment even more rigorous than the sport itself. These criteria can be met by properly completing the final phase of rehab. Much of the exercises remain the same from phase III, but the speed and efficiency needs to increase in order to come closer to a return to sports. The difficulty and impact of phase IV increases quite a bit. The landings and different types of jumping, including multi-directional, will require more balance and strength in order to perform properly. The strengthening aspect must continue to make an effective return to sports as well. Single leg strength lifts like single leg dead lifts, single leg squats, and single leg eccentric work should be intensified and be done pain-free and effectively. It sounds like a lot, but it is paramount to gain as much strength in addition to developing proper landing and jumping habits before thinking about making a return to sports. 

The final aspect of this injury that is worth talking about, is the diet the patient should take up after surgery. It is important to eat healthy to avoid gaining excess weight during the time off. The most important food groups are proteins and carbs. Protein will help nourish the graft and build a shield around it. Carbohydrates will fuel the muscles allowing them to perform at higher levels during rehab sessions. It is also important to eat leafy greens rich in vitamins. Leafy greens like kale and collard greens help fight inflammation. Eating the leafy green foods will also stop scar tissue from developing after exercise which will make the patient feel better. Fatty fish and other seafood will also help fight inflammation. There will be lots of time where exercise will not be an option, so a proper diet is essential for athletes who plan on staying in the best shape possible as well as speeding up the healing time of the injury.

ACL surgeries are not yet 100% effective. While they have improved exponentially in the last twenty-five years, they are still not perfect and the protocols to return to activity and sport can vary vastly. There are plenty of opinions on the best way to rehabilitate the knee, repair the knee, and when an athlete is ready to return to competition. It is vital that the athlete take each stage of of the recovery seriously. Each stage has its own reason for being the most important which is why they must not be taken lightly. Even the most basic exercises have a great importance to the development of muscle and protecting the ACL graft. It is important to remember through all of this, that everyone is different and will complete the goals of recovery at different times. Faster is not always better. Emphasizing range of motion early and proper mechanics later will lead to a stronger graft and leg as a whole. There are times where athletes must listen to their leg and take time off should pain arise. It is all part of a long process. In order to return quickly a patient must be effective in his/her rehab, but just because they are effective, does not mean they will return quickly.
