Anterior Cruciate Ligament (ACL) injury

About the hottest topic when it comes to sports injuries are the dreaded ACL injuries!

What is the Anterior Cruciate Ligament (ACL)

The anterior cruciate ligament (or ACL for short) is a ligament that sits within the knee joint. Ligaments are thick, strong, fibrous structures, designed to prevent excessive movements of the joint, providing overall stability. In this case, the ACL provides stability to our knee joint by preventing excessive forward movement of the shin bone relative to the thigh bone.

Knee Joint

The knee joint is the largest joint in the body and is responsible for supporting the weight of the body and allowing for a wide range of movements such as bending, straightening, and rotating the leg. It is a hinge joint that connects the femur (thigh bone) to the tibia (shin bone) and the patella (kneecap).

The knee joint is composed of several components, including bones, cartilage, ligaments, tendons, and muscles. The articular surfaces (the parts make contact with each other) of the femur, tibia, and patella are covered with smooth cartilage that allows for smooth movement of the joint. The meniscus, a C-shaped piece of cartilage, also helps to absorb shock and distribute weight within the joint.

Ligaments and tendons provide stability to the joint. In addition to the anterior cruciate ligaments (ACL), other ligaments include the posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL). The quadriceps and hamstring muscles and tendons also play a role in stabilizing the knee joint and allowing for movement.

Injuries to the knee joint, such as ACL injuries, meniscus tears, or ligament sprains, can cause pain, swelling, and instability in the knee. Treatment options for knee injuries depend on the severity of the injury and may include rest, physical therapy, bracing, medications, or surgery. A doctor or physical therapist can help determine the most appropriate course of treatment based on an individual’s specific needs and goals.

How do ACL injuries occur?

The most common ACL injuries include sprains, partial tears and ruptures. We can look at these as a spectrum of injuries, starting with a sprain, being an “overstretching” of the ligament fibres, progressing to a partial tear, or full anterior cruciate ligament rupture.

As great it would be to have an interesting and traumatic tale to tell about ACL injuries, unfortunately most ACL tears are non-contact. Two typical mechanisms are hyperextension of the knee joint or excessive inwards movement. These often occur in cutting and direction changing sports including Football, Netball, AFL, Basketball and skiing. Occasionally, we can succumb to a contact injury, when there is a direct blow to the outer part of the knee, forcing it inwards.

Often ACL injuries are not standalone. Because of type of movement the knee joint is exposed to, it could result in what we call the “unhappy triad”, where we see a tear in the anterior cruciate ligament, medial meniscus and medial collateral ligament. Meniscal injuries are commonly associated with ACL tears or partial tears.

It is also important to note with ACL injuries, that aside from soft tissues being injured or stressed, the knee joint can experience a bone contusion especially on the lateral femoral condyle (outer side of the knee), which is essentially bruising underlying the articular cartilage. The lateral side of the knee joint is compressed as the ACL tears, causing compressive forces on the lateral femoral condyle (1).

These bony type of associated injuries may not influence immediate management, however long term, we need to take into consideration early development of osteoarthritis of the injured leg. This is well documented in the research, and we know that “previous trauma” of the knee joint is a risk factor for developing osteoarthritis.

How is an ACL tear diagnosed?

Anterior Cruciate Ligament injuries are typically diagnosed by your health professional, predominantly being your general practitioner or physiotherapist. But let us be real, your physiotherapist is likely to have a better understanding of the possible risk of an ACL tear.

We have three primary tests to look for an Anterior Cruciate Ligament tear, but usually if injury is suspected, follow-up imaging (typically an MRI) is the way to rule in an ACL tear or ACL rupture. The diagnosis will definitely change our course of management, so confirmation through imaging is important to guide the following recovery process. Generally, a consultation with orthopaedic surgeons is appropriate to assist in diagnosis.

Sometimes, particular orthopaedic testing such as an anterior drawer test are not always conclusive of injury, hence MRI tends to be the gold standard for identifying the extent of your ACL injury. However, with a thorough history taking and physical exam, we have a good suspicion for ACL injuries.

Who is most likely to experience an ACL injury?

Biomechanics, particularly the promotion of “correct/efficient” biomechanics has always been a buzz word when it comes to injury prevention. However, it is not that simple and the current body of literature for ACL injury prediction is for the most part inconclusive or at the very least conflicting.

We can conclude on particular demographics that are at an increased risk of ACL injuries, including the following;

• Female athletes
• Participating in cutting sports
• Prior Anterior Cruciate Ligament rupture
• Have a family history of Anterior Cruciate Ligament rupture – so yes, you can blame your siblings

How long do ACL injuries take to heal?

The traditional thought process is that the Anterior Cruciate Ligament won’t heal, but recently there has been a shift in our way of thinking! There is some good evidence that even a complete Anterior Cruciate Ligament rupture can heal with appropriate time and conservative rehabilitation. This is not always the case and there is ongoing investment into researching who best responds to conservative management.

What are my options for recovery?

In Australia, we have one of the highest turnovers of Anterior Cruciate Ligament reconstructions worldwide. It is almost always the first approach to managing an acute Anterior Cruciate Ligament tear/rupture, but in the last decade there is a growing body of evidence promoting a conservative approach. This means no surgery and a structured, progressive rehabilitation program with the intention of full return to sport.

A recent study showed the possible intrinsic healing potential of the ACL, indicating a higher healing potential in proximal ruptures. The results suggested the importance of a conservative period with joint strengthening, bracing to limit knee laxity, early mobilisation, and weight bearing as tolerated (2).

Surgically, when we talk about an ACL “reconstruction”, we are aiming to make a new ACL from a few different sources. The more common option in Australia tends to be a hamstring tendon graft, where they take part of your hamstring tendon, and anchor that into your knee to make a new ACL. Over time this will change in structure to act just like your ACL. Alternatives include the patella tendon, a donor graft and sometimes even a donor tendon from a family member!

ACL surgery versus conservative approach

The decision between ACL surgery and a conservative approach (non-surgical treatment) for an ACL injury depends on several factors, including the individual’s activity level, age, overall knee stability, associated injuries, and personal preferences. Both options have their own advantages and considerations, and it’s important to consult with a medical professional to determine the most appropriate course of treatment. Here are some key points to consider for each approach:

ACL Surgery:

Restoring knee stability: ACL reconstruction surgery aims to restore the stability of the knee joint by replacing the torn ACL with a graft. This can help prevent episodes of instability and decrease the risk of further damage to other knee structures.

Return to high-demand activities: Surgery is often recommended for individuals who engage in high-impact or pivoting sports or activities that require a high level of knee stability. ACL surgery followed by proper rehabilitation can allow a safe return to these activities.

Reduced risk of secondary injuries: ACL tears can lead to additional knee injuries, such as meniscal tears or cartilage damage. Surgical reconstruction may help reduce the risk of these secondary injuries.

Rehabilitation and recovery: Following surgery, a structured rehabilitation program is crucial to regain strength, range of motion, and function in the knee. Rehabilitation can take several months, and a dedicated commitment to the process is necessary for optimal outcomes lowering your risk of another ACL tear when returning to sport.

Conservative Approach:

Low-demand individuals: Non-surgical treatment may be considered for individuals who have a relatively low activity level, have minimal instability symptoms, or do not engage in high-risk sports or activities.

Rehabilitation and bracing: Conservative treatment typically involves a focused rehabilitation program, including exercises to strengthen the surrounding muscles and improve knee stability. In some cases, a brace may be used for added support during activities.

Possible functional recovery: Some individuals with an ACL tear can regain functional stability and return to their regular activities through physical therapy, muscle strengthening, and proprioceptive training. However, the likelihood of complete functional recovery without surgery is generally lower compared to surgical reconstruction.

Risk of instability: Without surgical intervention, the risk of recurring episodes of knee instability may be higher, particularly during activities that involve cutting, pivoting, or sudden changes in direction.

Lower cost: the research has shown that taking a conservative approach first, has an easier strain on your wallet, as well as the health system. It also remains cheaper even for those who start out on the path of rehabilitation for 6 months and eventually opt for a surgical repair.

Ultimately, the decision to pursue ACL surgery or a conservative approach should be made in consultation with a medical professional who can assess individual circumstances and goals, taking into account factors such as activity level, functional requirements, and associated injuries.

The evidence is changing! Recent evidence-based reviews on both conservative and surgical approach groups found similar results with reference to pain levels, symptoms, knee function, return to sport, quality of life, further meniscal tear and surgery rates, and radiographic osteoarthritis of knee prevalence (3)(4). It will be interesting to which way the research starts to sway as more people opt for a conservative approach to avoid surgery.

How long does it take to recover?

Best to set your expectations for the long haul. Recovery from an ACL rupture whether going surgically or conservatively is 9-12 months. Research promotes a delayed return to sport and every month you wait after 9 months drastically reduces your ACL injury rate.

 Conservative rehabilitation: what does it look like?

Conservative rehabilitation can be an option for some individuals with a mild to moderate anterior cruciate ligament (ACL) injury, particularly those who are less active or who do not participate in high-demand activities such as sports. Conservative rehabilitation aims to reduce pain, improve range of motion and strength, and restore function to the knee joint without surgery.

Conservative rehabilitation for an ACL injury typically involves physiotherapy and may include the following components:

Rest and protection: Initially, rest and protection of the injured knee is important to prevent further damage and allow the knee to recover. This may involve bracing or the use of crutches.

Physiotherapy: Physiotherapy can help to improve range of motion, reduce pain and swelling, and strengthen the muscles around the knee joint. Exercises may include stretching, range of motion exercises, and strengthening exercises for the quadriceps, hamstrings, and other muscles around the knee.

Activity modification: Individuals may need to modify their activities to avoid movements that put stress on the knee joint or to avoid high-impact activities altogether.

Pain management: Pain management strategies such as icing, heat therapy, and over-the-counter pain medications may be used to help manage pain and inflammation.

Monitoring progress: Regular check-ins with a healthcare provider or physiotherapist are important to monitor progress and adjust the rehabilitation plan as needed.

Conservative rehabilitation may be appropriate for individuals with a mild to moderate ACL injury, but it is important to note that this approach may not be effective for everyone. In some cases, surgery may be necessary to fully restore function to the knee joint. A healthcare provider can help determine the most appropriate treatment plan for an individual’s specific needs and goals.

Types of exercises

Strengthening exercises are an important component of rehabilitation following an anterior cruciate ligament (ACL) injury. However, it is important to work with a physiotherapist to develop an appropriate exercise plan for the individual’s specific needs and goals. Some types of knee strengthening exercises that may be included in a rehabilitation plan for an ACL injury include:

Quad sets: Quad sets involve contracting the quadriceps muscles at the front of the thigh while sitting or lying down with the legs straight.

Straight leg raises: Straight leg raises involve lifting the leg straight up while lying down, with the knee fully extended.

Hamstring curls: Hamstring curls involve bending the knee and bringing the heel toward the buttocks while lying down or standing with a resistance band or weight.

Wall squats: Wall squats involve leaning against a wall with the feet shoulder-width apart and the knees bent at a 90-degree angle and holding the position for several seconds.

Step-ups: Step-ups involve stepping up onto a platform or step with one foot and then lowering back down, while keeping the knee in line with the ankle.

Lunges: Lunges involve stepping forward with one foot and bending the knee while keeping the other leg straight behind.

Single-leg balance exercises: Single-leg balance exercises involve standing on one leg and maintaining balance for several seconds.

It is important to start with low-intensity exercises and gradually increase the intensity and duration of exercise over time as the knee joint heals and strength improves. It is also important to avoid exercises that put excessive stress on the knee joint or that cause pain or discomfort. A healthcare provider or physiotherapist can help develop a rehabilitation plan that is appropriate for your individual needs and goals.

If you are looking to get back into a high level of sport again, gym access is almost necessary to be able to progress your exercises to a level which will help restore your knee function back to sporting fit!

Stages of recovery following ACL reconstruction

Rehabilitation following an anterior cruciate ligament (ACL) injury or surgery is a gradual and progressive process that can take several months. The stages of ACL rehabilitation can vary depending on the severity of the injury, the individual’s goals, and the surgeon’s preferences, but they generally include the following:

Pre-habilitation: This phase occurs prior to surgery and focuses on improving strength, range of motion, and flexibility in the knee joint to prepare the individual for surgery. It is beneficial to get swelling down prior to surgery.

Early stage rehabilitation (0-6 weeks): This phase focuses on reducing pain and swelling, improving range of motion, and gradually increasing weight-bearing activities with the help of crutches.

Intermediate stage rehabilitation (6-12 weeks): This phase focuses on improving knee stability and strength, increasing endurance, and gradually increasing the intensity and duration of exercise.

Late stage rehabilitation (12 weeks and beyond): This phase focuses on returning to running, sports (6 months +) or other activities, with an emphasis on sport-specific exercises and activities that simulate the demands of the individual’s chosen activity.

Throughout the rehabilitation process, physiotherapy is often an important component to help individuals regain strength, mobility, and function in the knee joint. Other treatments, such as icing, heat therapy, and massage, may also be used to manage pain and swelling.

It is important to follow a rehabilitation program carefully and consistently to achieve the best possible outcome following an ACL injury or surgery. Individuals should work closely with their healthcare provider and physiotherapist to monitor progress and adjust the rehabilitation plan as needed.

Guideline to stages of recovery following ACL reconstruction

Early Stage recovery (0 to 6 weeks)

After an Anterior Cruciate Ligament injury, whether you will undertake the surgical option or not, physiotherapy management should focus on regaining the range of movement in your injured knee, strength, proprioception and stability. In the acute stage, PRICE principal should be used in order to help reduce swelling and pain, to attempt to regain full range of motion and to decrease joint effusion. If pain is severe, then anti-inflammatory medications can be used to help control pain and swelling.

• Protect
• Restricted movement
• Ice
• compression
• elevation

In very unstable injuries or discomfort post surgery, the use of crutches and a knee brace could be appropriate for some patients. Generally, we try to avoid this and promote normal function as soon as possible, extended use of the knee brace and crutches should be limited to avoid quadriceps atrophy.

In the early stages, neuro-muscular inhibition of the quadriceps caused by joint effusion may have a negative effect on early stage strengthening exercises. In any case exercises should commence early to encourage range of movement, initial strengthening of the quadriceps and hamstrings, and even joint proprioception. It is an unknown fact, that strength and proprioceptive alterations occur in both the injured and uninjured limb.

Intermediate stage rehabilitation (6-12 weeks)

The intermediate stage of rehabilitation following ACL repair surgery typically occurs between 6 to 12 weeks post-surgery. During this stage, the focus is on improving knee stability and strength, increasing endurance, and gradually increasing the intensity and duration of exercise. Some key components of intermediate rehabilitation for ACL repair may include:

Range of motion exercises: Continuing to work on improving knee range of motion through stretching and other exercises.

Strengthening exercises: Progressing to more advanced strengthening exercises for the quadriceps, hamstrings, and other muscles around the knee, such as leg presses, lunges, and step-ups. Resistance training with weights, resistance bands, or other equipment may be incorporated.

Balance and proprioceptive training: Incorporating exercises to improve balance, stability, and proprioception (the sense of body position and movement), such as standing on a balance board or foam pad.

Plyometrics: Gradually introducing plyometric exercises, such as jumping and hopping, to improve neuromuscular control and prepare for more advanced activities.

Cardiovascular exercise: Starting low-impact cardiovascular exercise, such as cycling or swimming, to improve endurance and cardiovascular fitness.

Sport-specific training: Incorporating sport-specific exercises and activities that simulate the demands of the individual’s chosen activity, with the guidance of a physiotherapist or sports medicine specialist.

Throughout the intermediate stage of rehabilitation, it is important to continue to monitor progress and adjust the rehabilitation plan as needed. Regular check-ins with a healthcare provider or physiotherapist can help ensure that the individual is progressing appropriately and safely towards their goals. It is important to avoid high-impact activities or movements that could put excessive stress on the healing knee joint, and to continue to use any necessary bracing or other support as recommended.

Late stage rehabilitation (12 weeks and beyond)

The later stage of rehabilitation following Anterior Cruciate Ligament repair surgery typically occurs between 12 weeks to 6 months post-surgery. During this stage, the focus is on returning to full function and activity, including sport-specific activities. Some key components of later stage rehabilitation for Anterior Cruciate Ligament repair may include:

Strengthening exercises: Continuing to progress strengthening exercises for the quadriceps, hamstrings, and other muscles around the knee. Resistance training with weights, resistance bands, or other equipment may be incorporated to continue to build strength and endurance.

Plyometrics: Continuing to progress plyometric exercises, such as jumping and hopping, to improve neuromuscular control and prepare for more advanced activities.

Agility and sport-specific training: Incorporating agility drills, sport-specific exercises and activities, and other movements that simulate the demands of the individual’s chosen activity, with the guidance of a physiotherapist or sports medicine specialist. This may involve practicing cutting, pivoting, and other sport-specific movements.

Running and other cardiovascular exercise: Gradually reintroducing running and other high-impact cardiovascular exercise, with the guidance of a healthcare provider or physiotherapist.

Balance and proprioceptive training: Continuing to incorporate exercises to improve balance, stability, and proprioception.

Return to sport: Assessing readiness to return to sport or other high demand activities, and developing a plan to safely reintroduce these activities.

Throughout the later stage of rehabilitation, it is important to continue to monitor progress and adjust the rehabilitation plan as needed. Regular check-ins with a healthcare provider or physiotherapist can help ensure that the individual is progressing appropriately and safely towards their goals. It is important to gradually reintroduce high-impact activities and to continue to use any necessary bracing or other support as recommended.

Post 6 months ACL reconstruction

Post 6 months rehabilitation following Anterior Cruciate Ligament repair surgery typically focuses on maintaining and improving the gains made during earlier stages of rehabilitation and continuing to progress towards full function and activity. Some key components of this stage of rehabilitation may include:

Continued strengthening exercises: Continuing to perform strengthening exercises for the quadriceps, hamstrings, and other muscles around the knee to maintain strength and endurance.

Continued plyometrics and sport-specific training: Continuing to progress plyometric exercises, agility drills, sport-specific exercises and activities, and other movements that simulate the demands of the individual’s chosen activity. This may involve more complex and challenging exercises as the individual’s strength and function improve.

Running and other high-impact activities: Gradually increasing the intensity and duration of running and other high-impact activities, with the guidance of a healthcare provider or physiotherapist. This may involve incorporating interval training, speed work, or other advanced training techniques.

Proprioceptive and balance training: Continuing to incorporate exercises to improve balance, stability, and proprioception.

Return to full activity: Assessing readiness to return to full activity, including sport, work, and other high-demand activities, and developing a plan to safely reintroduce these activities.

Injury prevention: Developing an ongoing injury prevention plan, including exercises and techniques to reduce the risk of re-injury or new injuries.

Throughout this stage of rehabilitation, it is important to continue to monitor progress and adjust the rehabilitation plan as needed. Regular check-ins with a healthcare provider or physiotherapist can help ensure that the individual is progressing appropriately and safely towards their goals. It is important to continue to use any necessary bracing or other support as recommended and to follow a maintenance program to continue to improve and maintain strength, stability, and function over the long-term.

Lilyfield Physio Sports Injury Services

At Lilyfield Physio we have a wealth of experience when it comes to sporting injuries. If you have suffered a serious injury like an ACL tear or rupture, come and talk to us about your options and paths to recovery. Sports medicine has evolved and surgery is not always the first option, taking a conservative approach with a well-structured rehabilitation plan may be right for you.

We are lucky as we have Kam Bhabra who worked in the English Premier League (EPL) for 6 years with Arsenal Football Club, where he helped many professional footballers return to sport following ACL surgery.

Further, our team has even more sports experience with both Marc Rahme and Aedon Wilson having a variety of sporting experience, both as competitors and as treating practitioners. Click on their names for further  information.

References

1) Bone bruises associated with ACL rupture: correlation with injury mechanism. Viskontas DG, Giuffre BM, Duggal N, Graham D, Parker D, Coolican M. Am J Sports Med. 2008 May;36(5):927-33. Epub 2008 Mar 19.

2) Healing potential of the anterior cruciate ligament in terms of fiber continuity after a complete rupture: A systematic review Alexios Pitsillides a, Dimitrios Stasinopoulos b, Konstantinos Giannakou a; Journal of Bodywork and Movement Therapies, Volume 28, October 2021, Pages 246-254

3) Is reconstruction the best management strategy for anterior cruciate ligament rupture? A systematic review and meta-analysis comparing anterior cruciate ligament reconstruction versus non-operative treatment. Smith TO, Postle K, Penny F, McNamara I, Mann CJ. The Knee. 2014 Mar 1;21(2):462-70.

4) Surgical versus conservative interventions for treating anterior cruciate ligament injuries. Monk AP, Davies LJ, Hopewell S, Harris K, Beard DJ, Price AJ. Cochrane Database of Systematic Reviews. 2016(4).

5) Primary surgery versus primary rehabilitation for treating anterior cruciate ligament injuries: a living systematic review and meta-analysis. Saueressig T, Braun T, Steglich N, et al. British Journal of Sports Medicine 2022;56:1241-1251.

6) Kiss goodbye to the ‘kissing knees’: no association between frontal plane inward knee motion and risk of future non-contact ACL injury in elite female athletes. Agnethe Nilstad, Erich Petushek, Kam-Ming Mok, Roald Bahr & Tron Krosshaug. Sports Biomecahnics 2023;22:1, 65-79