HomeSports 2.0ACL Injury: Types, Causes, Symptoms, How to recover | Rehab Station
-- Advertisement --

ACL Injury: Types, Causes, Symptoms, How to recover | Rehab Station

- Advertisement -

ACL injuries- We have often heard about them, then may it be in football, basketball, American football, or downhill skiing. We all identify ACL injury as the worst form of sports injury. ‘Worst’ because it has the power to rule athletes out for months, not weeks.

-- Advertisement --

Remember how Zlatan Ibrahimovich recovered from an ACL injury in just 7 months? ‘Lions don’t recover like humans!’ was how the footballer funnily described his recovery. However mind-boggling as the comeback may be, it proves that even the most incredibly fit footballers like Ibrahimovic are also susceptible to ACL injuries.

-- Advertisement --

His neat comeback game against Bristol City provides evidence of how well one can recover quickly from such a dreadful injury. Let’s get to know more about the ACL injury and the secrets about how to avoid it.

What is ACL?

Anterior cruciate ligament in the knee joint is one of the two ligaments inside the middle section of the joint that forms an X. The primary function of this ligament is to prevent the leg from moving excessively forward and excessive rotations at the knee joint.

ACL Injury KreedOn
Credits Rehab Station

sports biomechanics | KreedOnAlso Read | Sports Biomechanics

-- Advertisement --

Causes of ACL Injury

The main causes of ACL injury are:

Causes of ACL KreedOn
Credits Rehab Station

Other than the above-stated causes, valgus (outward movement of the leg with respect to the thigh), muscular imbalance (weakness and tightness) can also increase the chance of ACL injury.

History of ACL injury in the past also increases the possibility of a re-injury if the rehabilitation was not adequate. If another injury accompanies the ACL injury to any other structure of the knee joint like Collateral ligaments or meniscus, it is possible to delay the recovery.

Injured Knee KreedOn
Credits Physio Works

Types of ACL Injury

Anterior Cruciate Injury KreedOn
Type/ Degrees of injury
Grade 1
  • The ACL ligament is pulled. No tear.
  • No joint instability.
Grade 2
  • Less than 50% fibres of the ACL are torn: Partial tear.
  • Minimal joint instability.
Grade 3
  • 50-100% fibres of ACL are torn: Complete tear
  • Joint is unstable. Giving away sensation may be present.
ACL deficient knee
  • No ACL since birth.
Unhappy triad
  • ACL injury + Medial collateral ligament (MCL) injury +           medial meniscal injury

Badminton Injuries KreedOnAlso Read | 5 Most Common Badminton Injuries and How to Avoid them

Symptoms of an ACL injury

If a grade 3 injury to the ACL occurs during play or during a fall, a distinct popping sound is audible. This may be accompanied by an inability to weight bear on the injured knee due to instability often described as ‘the knee was giving way’.

As grade 3 tears involve complete disruption of the integrity of the ligament, people often feel a sudden sharp pain initially. It occurs most commonly with a popping sound.

Instability, swelling and minimal pain (maybe due to structures injured other than the ACL) form the classic symptoms of a grade 3 ACL injury. Grade 2 and grade 1 injuries often involve a lot of pain and swelling with minimal instability.

Treatment for ACL Injury

Surgical interventions often depend upon the physical demands of the patient’s life. It is possible to manage grade 1 and grade 2 tears. Apt rehabilitation and progressive exercises are crucial in prevention becoming grade 3 tears.

Surgical procedures, whether reconstruction or repair, are advised to young adults or people involved in an active lifestyle. It is often the treatment of choice where the patient wishes to continue with the sport or an active fitness regime after the injury as well.

Whether one undergoes surgery or no, REHABILITATION becomes a critical part of the recovery process.

Stages of ACL Rehabilitation

1. Conservatively managed ACL injury

Rehabilitation after an ACL injury starts immediately post-injury. The first aim is to protect the ligament and reduce the risk of further damage. Protection and optimal loading are critical.

A wide range of bracing products is now available in the market which can support the joint as per requirement. Blocking the terminal knee straightening and sudden twisting at the knee is key to this phase.

A physiotherapist can help to reduce the swelling, pain and maintain the range of motion at the knee to avoid stiffness. The physiotherapist also provides gait training assistance.

Maintaining or increasing muscle strength of hip and other limb muscles is also a goal in the early stage of injury using non-weight-bearing exercises.

Gradually, the brace is removed, and muscle strengthening and balance training are started to get an optimal hamstring: quadriceps ratio. Introduction of training for functional activities under the supervision and before proceeding with the next step as per the goal of the patient.

sports injury centreAlso Read | Where do athletes recover from sports injuries?

Dynamic stability and proprioceptive (joint position sense) training is an essential part of rehabilitation to avoid injury, regain functional independence, and pre-injury performance.

A systematic review conducted at the School of Physiotherapy, The University of Sydney, Australia, found that prognosis in ACL deficient knees is good with respect to knee function and performance.

But the activity levels drop to 21% after the injury. A person may not be able to reach their pre-injury activity status if the injury is managed conservatively. Thus, people who have a very active lifestyle (like athletes), or young individuals opt for the ACL reconstruction or repair surgery, as it is elective surgery.

2. Pre-operative

It is a well-established fact that any muscle that undergoes a surgical procedure, losses one clinical grade of strength. This makes pre-operative interventions crucial for better and faster recovery post-surgery. Exercises mainly focus on maintaining the available strength and involve specific immediate post-operative activities.

A study conducted at the University of Delaware by Mathew J. Failla and colleagues suggested that patients treated with preoperative rehabilitation consisting of progressive strengthening and neuromuscular training followed by a postoperative rehabilitation program were significantly better functionally.

A large percentage of this population (72%) was also seen to resume the pre-injury level of sports activities within two years.

3. Post-operative

Post-operative management mainly involves three phases. Each phase focuses on certain key factors.

Sprain vs Strain | muscle strain | Sprained ankle | KreedOnAlso Read | Sprain vs Strain

Phase I:

This phase usually spans the time from right after the surgery to about 6 weeks post-operatively. Main aims of this phase are to reduce pain, swelling, regain an optimal range of motion and strengthening.

Studies suggest that dealing with suture site pain is very much possible by using Transcutaneous Electrical Nerve Stimulations (TENS) as it works on the pain gate mechanism and causes the release of endogenous endorphins.

The functional range of motion can be achieved by gentle stretching for posterior capsule and active range of motion exercises.

In some instances, using a Controlled Passive Movement (CPM) machine is advocated if the patient is unable to flex the knee beyond a certain angle. Regaining this range is imperative to ensure the success of the surgery.

Strengthening exercises are graduated from isometrics within the brace to active strengthening regimes in open kinematic chain. Exercises targeted to increase joint position sense, and balance are also started in the early phase.

Phase II:

This phase takes between 6-12 weeks of the rehabilitation process. The foundations of this phase includes strengthening the muscles surrounding the knee joint, as well as obtaining an optimal Quadriceps: Hamstrings ratio form.

Close kinematic chain exercises (exercises in weight-bearing positions) form the lion’s share of the exercise protocol. Balance and proprioceptive training specific to the functional requirement is necessary to avoid re-injury and improve motor control.

Phase III:

This is the final phase of the rehabilitation process for individuals who do not lead an active sports lifestyle. The aim of the exercises in this phase is more towards refining motor control, strength, balance and proprioception. The most important goal of this phase is to make the operated limb equivalent to the healthy limb.

Return to Sports Phase:

Zlatan Ibrahimovic KreedOn
Zlatan Ibrahimovic returned to training just over a month after his ACL surgery, although it would take him another 6 months to get back on the field | Credits The Sun

This phase of rehabilitation is generally for those athletes or individuals who want to get back to a highly active lifestyle. It mainly involves simulation of a part or whole movement essential for the particular sport.

Knowing the sport demand and pre-injury level of the athlete is essential when designing the exercise program. Sport-specific goal-oriented training focusing on refining neuromuscular control is the highlight of this phase.

Initially, training is supervised and performed under a controlled environment and then transferred to the field. Performance enhancement and re-injury prevention strategies are also a part of the return to sport phase with its inclusion in future training also necessary.

Rehab KreedOnAlso Read | 9 Most frequent Sports Injuries: Prevention and Treatment

How to prevent an ACL injury?

It is possible to prevent an ACL injury by correcting muscular imbalance (strength and flexibility of muscles) in the lower body. Refinement of dynamic postures occurring during sports matches can eliminate faulty movement patterns. This could result in a reduction in injury risk.

For example, correction in the faulty landing after a jump during sports like badminton, basketball, volleyball, etc., can reduce the chance of an ACL injury.

Get the best advice about ACL recovery here!

ACL injuries have the potential of hampering your career, forever. And you won’t take chances with your career, would you? The physiotherapists at REHAB STATION are experts at tackling ACL injuries and can guide you well in preventing them.

REHAB STATION  is a sport and musculoskeletal centric sports physiotherapy lab, situated in the heart of Pune city. The physiotherapists at REHAB STATION strive to live up to the statement that defines an ideal sports physiotherapist.

“Prevention is better than cure” is the least applied phrase in the modern world. REHAB STATION aims at spreading awareness regarding Preventive Rehabilitation. As sports physiotherapists, they can help you prevent injury and overcome the plateau in your performance!

Top 10 Best Nike Sports Shoes | KreedOnAlso Read | Top 10 Nike sports shoes | Best shoes for the maximum performances


What is an ACL injury?

An ACL injury refers to damage or tearing of the anterior cruciate ligament (ACL) in the knee joint. It commonly occurs during sports activities involving sudden stops, changes in direction, or direct impact to the knee.

What are the symptoms of an ACL injury?

Common symptoms of an ACL injury include severe pain, swelling, instability in the knee, a popping sound at the time of injury, limited range of motion, and difficulty bearing weight on the affected leg.

Can an ACL injury heal on its own?

The ACL does not have the ability to heal itself effectively due to limited blood supply. In most cases, surgical intervention is required to repair or reconstruct the torn ligament.

What are the common symptoms of an ACL injury?

Common symptoms of an ACL (anterior cruciate ligament) injury include sudden and severe pain in the knee, swelling, instability or a feeling of the knee giving way, limited range of motion, and difficulty walking or bearing weight on the affected leg.

Follow us on: InstagramFacebookYouTubeWhatsApp and be part of KreedOn’s community

For more sports knowledge and latest stories on Indian sports and athletes

Subscribe Now Receive exciting Indian sports stories on your WhatsApp now.
Rehab Station
Rehab Station
REHAB STATION is a high-performance sports physiotherapy rehab centre where they offer a unique combination of up-to-date manual therapy, exercise therapy and advanced electrotherapy.


  1. Hi. I would like to know which method of surgery treatment was used for zlatan? I have partial torn od acl and looking for the Best way how to get recover as soon as possible please. I kindly ask you for any advices please. Thanks you so much

    Best regards


Please enter your comment!
Please enter your name here