Anterior cruciate ligament injury symptoms types and treatment

The anterior cruciate ligament (ACL) injury is one of the most common injuries in sports that require sudden changes in direction, such as football and basketball. A tear in this ligament causes severe pain and significantly affects a person's ability to move. The severity of the injury ranges from a partial tear, which may be treated with physical therapy, to a complete tear that requires surgery to reconstruct the ligament. In this article, we will explore the types of ACL injuries, the symptoms to watch for, and the latest treatment methods that help restore movement quickly and safely. If you are experiencing knee pain or want to prevent such injuries, keep reading to learn more.

What is an Anterior Cruciate Ligament (ACL) Tear?

An ACL tear is an injury that occurs when the anterior cruciate ligament, one of the key ligaments in the knee, becomes twisted, stretched, or torn partially or completely. This injury is one of the most common knee injuries and often happens during sports that involve jumping, sudden changes in direction, or hard landings. As a result, the patient experiences swelling, pain, and may struggle with bearing weight on the knee.

Does the ACL Heal on Its Own?

Unfortunately, the ACL does not heal on its own completely because the tissue of the ligament lacks the ability to regenerate. Therefore, the treatment depends on the severity of the injury and the individual's activity level. It may involve surgical or non-surgical treatment options.

Stages of an ACL Injury:

Stage 1: Injury and Diagnosis
- Initial Symptoms:
  - Severe pain in the knee with a "pop" sensation at the time of the tear.
  - Swelling that develops rapidly after the injury.
  - A feeling of instability and difficulty standing or walking.
- Medical Diagnosis:
  - Clinical examination and tests like the "Lachman test."
  - X-rays or MRI scans may be used to determine the severity of the injury.
Stage 2: Immediate Treatment (Conservative Treatment)
- Conservative treatment is applied for less severe injuries (partial tears) and includes:
  - Rest: Avoid activities that place pressure on the knee.
  - Ice: To reduce swelling and pain.
  - Compression: Using a compression bandage to minimize swelling.
  - Elevation: Elevating the knee to help decrease swelling.
  - Pain relief: To alleviate pain and improve comfort.
  - Physical therapy: Simple exercises to improve knee mobility and strengthen muscles.
Stage 3: Decision on Surgical or Non-Surgical Treatment
- Non-surgical Treatment:
  - In cases of minor or partial tears, physical therapy and exercises to strengthen the muscles around the knee can be enough.
- Surgical Treatment:
  - For complete tears, doctors recommend surgery to replace the damaged ACL using either the patient's tendons or a donor's tendons.
Stage 4: Surgery and Early Recovery
- ACL Reconstruction: The damaged ACL is replaced using either the patient's tendons or a donor's tendons through minimally invasive arthroscopic surgery.
- Post-Surgery Care:
  - Rest and ice: To reduce swelling.
  - Physical therapy: To improve knee motion and strength.
  - Crutches may be needed for a period to avoid excessive pressure on the knee.
Stage 5: Rehabilitation and Full Recovery
- Advanced Physical Therapy: Post-surgery, physical therapy focuses on strengthening the knee and improving flexibility.
- Gradual Return to Sports: In 6 to 9 months, the patient can return to sports, but gradually and with the clearance from a medical professional and physical therapist.
Stage 6: Prevention of Future Injuries
- Prevention Program: After returning to sports, it is recommended to continue strengthening the muscles around the knee and improving balance.
- Proper Movement Techniques: Learning proper techniques and using knee protection gear can reduce the risk of re-injury.

Causes of an ACL Injury:

Intensive Sports Activities
- Sports that require rapid changes in direction, such as football, basketball, tennis, and volleyball, put significant pressure on the knee, increasing the risk of ACL injury.
- Sports that involve jumping, such as skiing or basketball, where sudden landings after jumps put excessive strain on the knee, also contribute to ACL injuries.
Sudden, Uncontrolled Movements
- Sudden stops: Quick halts during running or changes in direction increase the pressure on the ACL.
- Sudden twisting of the knee: This can happen during activities like slipping or twisting the knee while walking or running.
Direct Injuries (Collisions)
- Direct impact to the knee, such as a collision with another player in team sports (e.g., football, basketball), or falling and hitting the knee, can lead to an ACL tear.
Weak or Inflexible Muscles
- Weak thigh muscles can place increased strain on the ACL, making it more susceptible to injury.
- Muscular imbalances around the knee can cause uneven pressure on the ACL, increasing the likelihood of injury.
Improper Movement or Technique
- Incorrect techniques during sports activities can place excessive stress on the knee, which increases the risk of ACL injuries.
Genetic Factors
- Gender: Women are more likely to experience ACL injuries than men due to differences in movement patterns and muscle anatomy, with women often having a larger angle between the femur and tibia when bending the knee, which puts extra strain on the ligament.
- Heredity: Some studies suggest that genetic factors may play a role in ACL injuries, as certain individuals may have weaker ligaments or muscle strength.
Excess Weight
- Being overweight or obese increases pressure on the knees, which raises the risk of ACL injuries.
Aging
- As people age, the flexibility of ligaments and other connective tissues declines, making them more susceptible to injuries. This is exacerbated by a lack of physical activity or the natural changes in tissues over time.
Inadequate or Improper Training
- Insufficient warm-up or improper conditioning before participating in sports can lead to ACL injuries. Warming up helps strengthen the muscles around the knee and improve flexibility, reducing injury risk.

Symptoms of an ACL Injury:

Severe Pain
- Immediate severe pain is often felt upon injury, which may worsen with movement or weight bearing on the knee.
Swelling
- Swelling is a common symptom after an ACL injury, and it often develops within hours of the injury, making it difficult to bend or move the knee.
Popping Sound
- Many people report hearing or feeling a "pop" at the time of the injury. This typically signals a torn ligament.
Feeling of Instability
- Individuals may feel that their knee is "giving out" or feel unstable, especially when standing or walking. This occurs due to the loss of the ACL's role in stabilizing the knee joint.
Difficulty Moving the Knee
- After the injury, individuals often have trouble bending or straightening their knee completely.

If you experience any of these symptoms, it's important to seek medical attention promptly to determine the severity of the injury and start appropriate treatment.

6. Knee Sensitivity and Irritation

Increased sensitivity around the injured knee area may occur, with patients feeling tingling or a burning sensation when touching the knee.

7. Muscle Weakness

In cases of ongoing injury, the muscles around the knee may weaken due to pain or the inability to use them normally. This causes additional problems with movement and balance.

8. Feeling of Pressure Inside the Knee

The patient may feel a sense of pressure inside the knee due to swelling and pain, which can restrict knee movement and increase discomfort.

Types of Anterior Cruciate Ligament (ACL) Injuries

Grade 1 Injury (Mild Tear)
In this case, the ACL is slightly stretched or has a minor tear. There is no complete rupture of the ligament, and the knee’s stability is not significantly affected.
- Symptoms: Mild pain, slight swelling, minor instability.
- Treatment: Physical therapy is the first option to strengthen the muscles around the knee and improve stability.
Grade 2 Injury (Partial Tear)
This involves a partial tear of the ACL where the ligament remains partly connected, but it becomes unstable. The patient feels knee instability.
- Symptoms: Moderate pain, increased swelling, difficulty moving, feeling of instability.
- Treatment: Physical therapy may be effective, but in some cases, surgery may be required to repair the ligament.
Grade 3 Injury (Complete Tear)
This is the most severe type of injury, where there is a complete tear of the ACL, leading to total loss of the function and support that the ligament provides to the knee.
- Symptoms: Severe pain, significant swelling, total loss of knee stability, difficulty moving the knee.
- Treatment: In grade 3 injuries, surgery is the best option to reconstruct the ACL using either the patient’s tissue or a donor’s tissue.

Prevention of Anterior Cruciate Ligament (ACL) Injury

Strengthening the Muscles Around the Knee
- Strengthen the Quadriceps and Hamstrings: Strengthening the muscles around the knee helps support the ACL, reducing pressure on it.
- Balance Exercises: Balance exercises such as standing on one leg or using a balance ball can improve stability and help prevent injuries caused by unbalanced movements.
Specific ACL Prevention Exercises
Specialized training programs aim to strengthen muscles and improve movement skills to reduce the risk of injury, such as:
- Plyometric Training: Focuses on improving power and speed while enhancing movement control.
- FIFA 11+ Program: A program that includes exercises to improve balance, body control during sudden movements, and reduce actions that may put stress on the knee.
Improving Movement Techniques
- Landing Techniques: Teaching athletes how to land properly after jumping is crucial. Landing with bent knees rather than straight knees helps reduce pressure on the knee.
- Avoid Twisting the Knee During Sudden Stops: Athletes should be trained on stopping or changing direction without putting excessive stress on the knee.
- Avoid Movements That Twist the Knee: Movements that involve sudden rotation or running while twisting the knee increase the risk of injury, so they should be avoided.
Proper Warm-Up Before Exercise
A proper warm-up is important for improving muscle and ligament flexibility, reducing the chances of injury. The warm-up should include exercises to raise body temperature and mobilize the joints.
Warm-up exercises can include light jogging, dynamic stretching, mobility jumps, and other exercises targeting the knee.
Flexibility and Stretching
Maintaining flexibility through regular stretching helps reduce tension and pressure on the knee.
Dynamic stretching exercises such as leg raises or light jogging help improve muscle flexibility around the knee.
Wearing Proper Footwear
Good quality sports shoes provide adequate support to the feet and ankles, reducing the impact of sudden movements on the knee. Make sure the footwear is appropriate for the specific sport and provides good support for the ankle and foot.
Using Protective Equipment
In some sports, special knee protectors such as braces or straps can be used. These devices may provide some support to the ACL and reduce the risk of injuries. However, it’s important to note that protective gear cannot replace proper training.
Adequate Rest and Recovery
- Sufficient Rest Between Exercises: Overtraining can lead to knee fatigue and increase the risk of injury. Ensure that the body gets enough recovery time between sports activities.
- Post-Injury Rest: If you have previously injured your ACL, you should follow a rehabilitation plan and undergo physical therapy before gradually returning to sports.
Environmental Awareness
- Safe Training Environment: Make sure that the floor where you train is properly covered and suitable for the sport. Slippery or uneven surfaces increase the risk of injury.
- Weather Conditions: If practicing outdoors, ensure that weather conditions do not affect safety. Wet or frozen ground can lead to accidents and injuries.
Diet and Bone Health

Proper Nutrition: Maintaining joint and bone health through a healthy diet is essential in preventing injuries. Ensure adequate intake of calcium and vitamin D to support bone health.
Supplements: In some cases, taking supplements like glucosamine and collagen can help improve joint health and support the ACL.

Treating an ACL Tear with Medications

Pain Relievers (Analgesics)
- Nonsteroidal Anti-inflammatory Drugs (NSAIDs):
  - Ibuprofen: Helps relieve pain and swelling, commonly used for knee injuries.
  - Naproxen: Similar to ibuprofen, used for pain relief and swelling reduction.
  - Acetaminophen (Paracetamol/Tylenol): Used for mild pain relief without affecting inflammation.
These medications work by reducing inflammation and relieving pain, improving comfort and movement in the injured knee.
Topical Pain Relievers
- Capsaicin or Menthol: These substances help to reduce pain locally when applied to the skin near the injured area.
- Diclofenac (Voltaren): A topical anti-inflammatory gel that helps reduce pain and swelling in the knee.
These topical treatments provide pain relief without the need for oral medications, minimizing potential side effects.
Anti-Inflammatory Drugs
- Corticosteroids:
  - Medications like Dexamethasone or Hydrocortisone may be prescribed to reduce inflammation and swelling in the knee. These should be used cautiously as they may cause side effects if used long-term.
- Cortisone Injections: In some severe cases, cortisone may be injected directly into the knee to reduce inflammation. However, these injections are temporary and help only alleviate symptoms, not solve the underlying problem.
Supplements for Cartilage and Joint Health
- Glucosamine: Believed to help strengthen joints and improve cartilage flexibility. It can be beneficial in supporting joint health during recovery from an ACL tear.
- Chondroitin: Often used with glucosamine to improve joint health and reduce pain.
- Omega-3 Fatty Acids: These help reduce inflammation and promote overall joint health, which can be helpful during recovery from an ACL tear.

5. Anti-inflammatory and Diuretics

In some cases, doctors may prescribe diuretics to help reduce swelling in the knee by decreasing the excess fluid in the joint, which contributes to improving comfort and movement.

6. Rest and Physical Therapy

In addition to medication, it is essential for the patient to follow a physical therapy program to improve knee movement and strength. Physical therapy includes:

Exercises to strengthen the muscles around the knee.
Improving knee flexibility.
Enhancing knee stability to prevent strain on the ACL during daily activities.

The patient should avoid activities that may strain the knee or increase pain, adhering to the prescribed rest period.

Types of Anterior Cruciate Ligament (ACL) Surgery

ACL Reconstruction
This is the most common surgery to replace the damaged ACL. The goal is to replace the damaged ligament with a new one, which can be obtained from the patient’s own tendons or from a donor.

Key steps of the surgery:
- Preparation: The type of tissue to be used for ACL reconstruction is determined. Tendons from the patient or from a donor can be used.
- Reconstruction: The surgery is done arthroscopically through small incisions in the knee. Tissue is extracted from the knee or Achilles tendons to replace the damaged ACL.
- Fixation: After obtaining the tissue, it is fixed in place using screws and special fixation materials to ensure the new ligament is stable.
- Recovery: Recovery begins gradually, with intensive physical therapy to rehabilitate the knee and improve its strength and range of motion.
Types of tissues used in surgery:
- Hamstring Tendon: The tendons are taken from the hamstring muscles at the back of the thigh, which are used as a replacement for the damaged ACL.
- Patellar Tendon: The tendon is taken from the area below the knee, including part of the surrounding bone. This is a traditional option.
- Allograft: In some cases, tissue from a living or deceased donor may be used. However, this option carries some risks, such as the body rejecting the tissue or potential infections.
Arthroscopic Surgery
Arthroscopic surgery is the most advanced and least invasive method for ACL replacement. The main advantage is that the surgery is performed through very small incisions, reducing the size of surgical wounds.

Advantages:
- Faster Recovery: As the surgery is done through small incisions, the recovery time is shorter compared to traditional surgery.
- Less Pain: Due to the small incisions, the pain associated with the surgery is much lower.
- Excellent Results: This surgery typically yields good results if the rehabilitation program is followed correctly.
ACL Repair Surgery
In some rare cases, the surgeon may attempt to repair the damaged ACL rather than replacing it completely. In this case, the torn ends of the ligament are stitched together.

Advantages:
- This method may be less invasive and allows for a quicker recovery.
Disadvantages:
- This method is not commonly used as it may not provide long-term stability like full ACL reconstruction. The repair might lead to long-term instability of the knee.
Ligament Transfer Surgery
This surgery involves transferring other ligaments from different parts of the body to replace the damaged ACL. This method is used in rare cases.

Rare Usage:
- This method is applied in special cases where neither the hamstring tendon nor the patellar tendon can be used, such as when available tissues are insufficient or unusable.

Post-ACL Surgery and Rehabilitation Stages

Stage One: Immediately After Surgery (First Week)
Main Goals:
- Reduce pain and swelling.
- Restore some knee movement.
- Prevent stiffness and promote circulation.
Actions:
- Rest and Ice: Apply ice to the knee to reduce swelling and pain in the early days post-surgery.
- Use Crutches: Crutches help reduce pressure on the knee and protect it.
- Pain Medications: Prescribed medications to alleviate pain during the first weeks.
- Elevate the Knee: Keep the knee elevated on a pillow to reduce swelling.
- Early Knee Exercises: Gentle exercises such as slight knee bending to improve range of motion.
Goal: Control swelling and pain, begin restoring limited knee movement.
Stage Two: Week Two to Month One (Improve Movement and Start Muscle Strengthening)
Main Goals:
- Restore full range of motion.
- Strengthen muscles around the knee (hamstrings and quadriceps).
- Reduce swelling and muscle tightness.
Actions:
- Movement Exercises: Exercises like knee bending and stretching to regain full movement.
- Intensive Physical Therapy: Focus on strengthening muscles around the knee, such as quadriceps and hamstring muscles.
- Limited Physical Activities: Gradual walking using crutches, avoiding overloading the knee.
- Compression and Elevation: Continue elevating the knee and using compression wraps to reduce swelling.
Goal: Increase knee range of motion, improve strength in surrounding muscles, restore daily movements.
Stage Three: Month Two to Month Three (Strengthen Muscles and Improve Endurance)
Main Goals:
- Improve muscle strength and flexibility.
- Start moving the knee normally.
- Gradually return to light physical activities.
Actions:
- Advanced Strengthening Exercises: Resistance training to build muscle strength, using light weights or machines.
- Balance and Coordination Exercises: Activities like standing on one leg or balance ball exercises to improve stability.
- Limited Sports Activities: Start light activities such as brisk walking, stationary cycling, or swimming.
- Avoid Activities Requiring Sudden Stops: Steer clear of activities that require quick direction changes.
Goal: Enhance muscle strength and endurance, restore natural knee movement, start returning gradually to physical activities.
Stage Four: Month Four to Month Six (Return to Light Sports Activities)
Main Goals:
- Restore normal movement.
- Begin returning to light sports activities.
- Enhance strength and motor coordination.
Actions:
- Advanced Strengthening Exercises: Challenging exercises like light jumps and heavy resistance training.
- Advanced Balance and Coordination: Using balance platforms and deeper muscle strengthening around the knee.
- Return to Light Sports: Start returning to activities like light jogging or fitness exercises.
- Return to High-Impact Sports: Return to high-impact sports such as football, basketball, or tennis.
Goal: Full knee stability, improve performance in sports, prepare for intense activities.
Stage Five: 6 to 12 Months (Return to High-Impact Sports)
Main Goals:
- Return to high-impact sports like football, basketball, or tennis.
- Ensure full knee stability.
- Improve athletic performance.
Actions:
- Intensive Sports Training: Improve athletic performance while maintaining knee stability with training exercises that mimic daily activities.
- Functional Evaluation: A doctor or physical therapist evaluates the knee’s readiness for high-impact sports. This evaluation includes strength, endurance, and balance assessments.
- Gradual Return to Sports: Start returning to sports requiring quick direction changes, like football or basketball, but cautiously.
Goal: Complete return to sports, ensure knee stability, fully strengthen muscles.