Knee Instability After ACL Injury: Causes and Management

The ACL (Anterior Cruciate Ligament) provides the stability of the knee joint. An ACL injury happens in the ACL area when it is torn or sprained. An ACL is one of the major ligaments which helps to connect the thigh bone to the shinbone. This is the most common ligament injury in the knee, and it mostly happens to athletes. It happens to them because they stop suddenly or change direction, jump a lot and land out of the sudden. It mostly happens in sports such as soccer, basketball and many others. The knee instability after ACL injury is very common during playing or doing some active activity. In this blog, we will understand about the knee instability after ACL injury and its surgical and non-surgical treatment. There are also the symptoms of knee instability and ACL injury and their causes too.

What is Knee Instability?

When you feel that your knee twists or moves side to side while doing common or daily activities, you must have knee instability. In this, you may feel weakness in the knee when you move or bend. Due to constant pain, you may not be able to straighten your leg.

Understanding ACL Injury

Here we will explain the ACL injury with some process, like how does it occurs and role of the ACL in knee stability. So, let’s understand these one by one.

How Does it Occur?

ACL injury occurs because of many reasons, but there are two reasons by which you can lead to this injury. So there are two mechanisms of ACL injury that occur:

• Non-Contact Mechanism ACL Injury: It mostly occurs in the sports like football, basketball, volleyball, etc. It happens when the player lands on one leg. This can also happen when the foot doesn’t move in the direction the player prefers.
• Contact Mechanism ACL Injury: It mostly happens in sports teams and can also impact the side of the knee, the hyperextension, or internal rotation position of the knee. It often happens in football, martial arts and many other sports.

Role of the ACL in Knee Stability

The knee is a combination of three main bones: the femur, the tibia and the patella, which is also referred to as the kneecap. These bones connect to the ligaments, which provide stability and support in movement. ACL is one of the four main ligaments which plays an important role in knee stability. It runs in the middle of the knee, and it connects the two opposite corners, which are the tibia and femur. It prevents the tibia from sliding out and shifting from its place to the femur. The ACL provides stability to the knee that is essential for athletic activities that involve quick motion and fast changes in direction.

Non-Surgical Treatment and Management for Knee Instability After ACL Injury

Non-Surgical treatment of knee instability includes:

• If you have swelling or pain, then you can rest or use ice on that area to reduce it.
• After being prescribed by the doctor, you can take Nonsteroidal anti-inflammatory drugs to help to reduce the pain and swelling.
• You can use the knee brace, which will help to support and to heal the knee. Consult with doctor to choose best knee braces for sports after ACL surgery, which are very helpful for athletes.
• You can do physiotherapy for knee pain or knee instability to improve the strength and movement of the knee.

It also depends on the type and severity of the issue. The RICE (Rest, Ice, Compression, Elevation) technique helps to improve the knee joint instability at home.

• Rest: It allows your knee to rest because it helps to heal and to reduce the swelling.
• Ice: Wrapping an ice pack in a cloth will help to ease the pain.
• Compression: Wrapped the injured area with the elastic bandage to reduce the swelling. The bandage should not be so tight as it can cause pain or swelling.
• Elevation: Putting the injured area on the soft pillows will help to reduce the swelling.

Surgical Treatment Options for ACL Injury

In this, you will get to know so many things like ACL reconstruction surgery, types of grafts and why we need to do ACL surgery. So let’s understand:

ACL Reconstruction Surgery

In this, we will tell you about the ACL reconstruction surgery based on their needs and the facts that we consider before this surgery.

Needs of the ACL Reconstruction Surgery

• Functional limitation: Some activities, like climbing, standing, walking for a long time, or doing similar things like that, can make the problem of ACL injury. It can lead to ACL ligament surgery.
• Reduced mobility: If your pain and inflammation have increased, then the movement of your knee is restricted, and it can reduce the mobility of the knee. And if you do any movement, then it can lead to knee pain.
• Muscle weakness and imbalance: Due to the ACL injury, the movement of the ankle and knee muscles becomes weak. It happens because of the less use of the affected area muscles.
• Fear of re-injury: Fear of re-injury and knee instability may affect daily activities and sports performance.
• Combined injuries: After suffering from the ACL tear and other injuries like the meniscus, the chances of developing osteoarthritis have increased.

Facts that we have to Consider before ACL Reconstruction Surgery

All ACL injuries need to be considered for surgery, but it depends on the factors that determine whether surgery will take place or not. So here are some factors which place the surgery:

• Severity of the injury: Patients who were suffering from partial ACL injury or ACL tear are treated with physiotherapy and braces. But those who were suffering from a complete ACL injury or ACL tear have to undergo surgery.
• Level of activity: If you are active and play sports, then you have to undergo surgery to recover fully so that you can play again. If you are not active and are not that young then you should go with the physical therapy only.
• Knee instability: If the condition of your knee is worse, getting unstable, or not able to do activities, then the surgery is important. Even if the person is suffering from many diseases or issues.

ACL Reconstruction Surgery Works

ACL reconstruction surgery involves the patient’s own tendon:

• Hamstring Tendon: This tendon is used more frequently.
• Peroneus Tendon: Selected cases are used in the peroneus tendon.
• Bone-Tendon-Bone (BTB): It is widely used in many countries due to strong fixation.

Types of Grafts (Autograft vs Allograft)

The injury, knee instability and future goals all these affects the surgical procedure. And every person has different knees. Graft is an innovation in modern medicine. It has many treatments that include bone grafting, reconstructive surgery, and burn care. In this method, they transfer the tissue even if it is within a person’s body or from the donor to a patients. It is a very critical replacement of damaged tissues. There are four types of grafts: autografts, isografts, allografts, and xenografts. In this, we will know the autograft and allograft.

Autografts

Autografts are used from a tendon from you, which is taken from the patellar tendon, quadriceps tendon and hamstring tendon. The patellar tendon was known as the gold standard in the past. All three of these options are effective and provide advantages. The use of autograft in reconstruction has many advantages. Like the tendon is from your own body (the patient’s body). So, there are minimal chances of getting any transmitted disease or rejection of the tendon. It is highly recommended for patients who are younger than 40, but there are chances for those who are more than 40 years old too.

Allografts

Allografts use a tendon from the donor to remake the ligament. If the tendon comes from a different person’s body, then there is slightly lower chance for patients to get any injury in that area from which they take out the body part. It is the easiest and smoothest way to recover, and the shortest time for the surgery as well. This is the best option for patients who are more than 40 and not planning to return to sports at a high level. The patients who have a lot of injuries in the knee and want to recover from them, then this is the best choice for them.

When is ACL Surgery Recommended?

You can opt for ACL surgery when:

• The person is suffering from a long-lasting sensation that their knee is loosening.
• The medical examination, your doctor found out that your ligament is too flexible.
• The MRI confirms that you have an ACL tear.

Rehabilitation After ACL Injury Treatment

In this session, you will understand the rehabilitation after ACL injury treatment. In which phases of ACL rehab program, timeline for recovery and what is the general classification by grades of ACL injury.

Phases of ACL Rehab Program

The ACL rehabilitation is divided into 5 phases. Now, let’s get to know these stages of phase one by one:

Phase 1 (0 to 10 Days): Laying the Foundations

Goals

• Reduce inflammation
• Protect the knee and healing tissue
• Achieve full extension
• Control the pain and swelling.
• Increase the motion level
• Quadriceps control
• Flexion to 90 degrees
• Aware of the education of patients

Recommended Actions

• Knee braces and crutches may be used depending on the surgeon’s recommendation.
• Apply ice for 20 min, 3 times a day.
• Normal moving exercise.
• Hip strengthening

Phase 2 (10 to 30 Days): Regaining Confidence and Movement

Goals

• Improve flexion
• Walk naturally
• Muscles strengthening
• Increase the quadriceps control

Recommendations actions

• Start walking without using crutches only if the knee is dry and has fully recovered.
• You should use a stationary bike to improve your flexion.
• Leg press and strengthening exercises should be performed under physiotherapist’s guidance.
• You should do the training with the hurdles, walk backwards on a treadmill.
• Do the standing quadriceps exercise.

Phase 3 (1 to 3 Months): Strength and Coordination

Goals

• Achieve 90% flexion
• Increase the quadriceps strength
• Improve the motor patterns
• Normalise the knee flexion

Recommendations Actions

• You should do functional balance exercise in one leg.
• Do light weights like global squats, etc.

Phase 4 (3 to 5 Months): Running and Plyometrics

Goals

• Start running again
• Keep improving the quadriceps and hamstrings strength.
• Transition to fitness.

Recommendations Actions

• Increase the level of the single-leg drill, like walking lunges, nordic hamstrings.
• Do low-level plyometrics like jumping, landing and controlling the movement.

Phase 5 (After 6 Months): Return to Sport

Goals

• Securely return to sports
• Do competition.
• Gain and maintain strength.

Recommendations Actions

• You should do functional testing like the single-leg hop, triple hop and crossover hop.
• Do sport-specific drills like jumps, pivots and decelerations.
• Collaborate with the coach, trainer or any person who is stronger than you.
• Do medical clearance before doing any competition, and it is mandatory.

Timeline for Recovery

There are 5 stages and a timeline to recover from ACL injury treatment:

Stage 1 (Weeks 0 to 2): Commencement Stage

The first stage is the most important in the recovery. In this

• To manage the movement and stabilise the knee, crutches and a knee brace are use.
• Reduce the stress.
• Had cold therapy

Goals

• Reduce and control the pain or the swelling.
• Help the body to achieve and maintain the full range of motion.
• Increase the mobility and strength.
• Pain management.
• Protecting the repaired ligaments.

Exercises

• Straighten leg raises
• Small knee bend

Do these exercises under the guidance so that you don’t face any problems further.

Stage 2 (Weeks 2 to 12): Restoring Mobility and Building Strength

The second stage is mainly focused on building up or increasing the level as compared to the first stage.

• It helps to increase the strength of supportive muscles that worsen after the surgery.
• It also helps patients to decrease the pain and improve their strength, so that they use a weight rather than crutches.

Goals

• Strong focus on the knee strength.
• Improving flexibility.
• Increase the level of quadriceps and hamstrings exercises.
• The mobility and strength improve.

Exercise

• It helps to achieve their full knee extension.
• 90-degree bending that helps in walking and doing daily activities.
• Strengthening exercise for the thigh.
• Hamstring muscles start to involve the muscles without adding pressure on the knee.
• Walk in the right posture to avoid improper habits.

Stage 3 (Weeks 12 to 16): Strengthening and Balance

• In the third stage, the recovery starts to begin.
• This helps to focus on improving the strength and maintaining the balance.
• During this time, the patients are able to move without using crutches.

Goals

• ACL injury recovery exercises will start.
• Improve knee stability and balance.

Exercises

• Using lightweight it helps to improve the strength in the muscles.
• Single-leg exercises, like balancing and squats, help to improve stability.
• Take physiotherapy sessions to confirm that the exercise you are doing is correct or not.

Note

• Continue doing the previous stages exercises. It will help to improve your level.

Stage 4 (Weeks 16 to 24): Preparing for High-Impact Activities

This is the fourth stage, and it is known as the preparation stage. By this patients starts to perform daily and sports activities.

• Patients can do simple motion activities like kicking footballs, shooting basketballs, basic throwing, and catching baseballs.
• Many patients do so much hard work in this stage because of the excitement of their easy comeback.
• For strength training, they have advanced and heavier weights to improve the muscles which is surrounding the knee.

Exercises

• Cardiovascular exercise, like swimming and cycling, helps to improve fitness without putting pressure on the joints.
• Doing sports movements like running in a straight line.

Stage 5 (Weeks 24 to 48): Full Recovery and Long-Term Maintenance

This is the fifth stage, and it happens approx after 6 months of surgery. In this,

• Patients get ready to do their daily activities.
• There is no more swelling in the knee.
• The legs have good quadriceps strength and movement of the knee.
• The patients have already great progress.
• In this, your knee should be strong, flexible, and stable.

Exercises

• Physiotherapy is mandatory to do daily.
• Do strengthening exercises on a regular basis to keep the knee strong.

General Classification by Degrees of ACL Injury

1st Grade

• Ligament fibres would be stretched with no tears.
• During the activity, there would be zero feeling of instability or insertion of the knee.
• There would be a feeling of stiffness and less swelling in the knee.

2nd Grade

• Ligament fibres would be torn partially.
• During the activity, there would be some feeling of instability and submission of the knee.
• There would be a feeling of stiffness and more swelling in the knee.

3rd Grade

• Ligament fibres would be completely torn. In this, the joints are divided into two parts or completely torn out of the socket.
• During the activity, there would be a feeling of instability and submission of the knee. The ligament also doesn’t perform the role of stabilising the knee.
• There would be the presence of the knee swelling of greater intensity.

Symptoms of Knee Instability and ACL Injury that You Should Not Ignore

Here are some knee problem symptoms for the knee instability and ACL injury, which are very important to know, and you should not ignore them.

Symptoms of Knee Instability

• Sensation and feeling of weakness, knee buckle or damage the ligaments.
• When the supportive structure of the knee is damaged, it causes pain.
• Inflammation causes swelling in the knee.
• Due to pain or swelling, the movement of the knee becomes less.
• The sounds of popping and clicking occur while moving the knee.

Symptoms of ACL Injury

• A loud “Popping” sound or sensation from the knee.
• Have a lot of pain and are not able to do daily activities.
• Difficulty in movement
• Pain in the knee.
• Increasing the swelling in the knee.
• The capacity for walking or moving is reduced.

Common Signs of Knee Instability

The most common signs of knee instability are:

• Severe pain in the knee
• Knee extension and flexion
• After many hours of injury, swelling occurs, and it increases gradually.

Main Causes of Knee Instability After ACL Injury

It happens because of twisting or moving the knee. It happens while doing sports or some activities, like while paying, when you suddenly stop, a sudden change of direction, accidentally or awkwardly land, sudden deceleration, direct impact or collision and pivoting with a fixed foot. Here are some common causes of knee instability and ACL injury

Causes of knee Instability

There are many causes of knee instability

Complete vs Partial ACL Tear

• Complete ACL Tear involves the breaking of the ligaments, and it helps to stabilise the knee. This injury occurs when someone suddenly stops, change of direction or accidentally lands. During the injury, people hear the sound of popping, which leads to swelling, pain, and instability. In this injury, it becomes hard to even carry weight, and it feels like the knee may give way at any time.
• Partial ACL Tear happens when the fibres of the ligament are torn, but other parts stay intact. It allows the knee to be stable. In this, patients might experience mild to moderate pain and swelling. In a partial ACL tear, the knee needs support for weight and daily activities.

Muscle Weakness and Imbalance

Weakness in the muscles which is surrounding the knee, mainly in the quadriceps and hamstrings, can reduce the stability. Strong thigh and calf muscles are need to support the knee. Weakness. overuse or injury from the bad or poor condition can weaken the stability.

Ligament Injuries

It is one of the most common causes of knee instability. There are four ligament injuries support and control the knee movement to stabilise the knee joint:

• Anterior Cruciate Ligament: ACL injury is very common in athletes. Some minimum tears can heal with physiotherapy and rehabilitation, but major injuries need surgery.
• Medial Collateral Ligament: MCL injury always happens due to the impact on the knee. In this injury, the possibility of the surgery is less.
• Lateral Collateral Ligament: LCL injury is as same as the MCL injury that happens due to the impact on the knee pain. It causes outside knee pain, and the requirement for surgery is less.
• Posterior Cruciate Ligament: PCL injuries are also referred to as the dashboard injury. It often happens when the tibia is pushed backward, which occurs in a car accident.

Tendon Injuries

Tendons that is around the knee, like the quadriceps or patellar tendons, can be strained, inflamed and cause knee instability. It helps to control the proper knee function. Any injury to these tendons reduces the joint support or knee movement and leads to the instability.

Meniscus Tears

It is a piece of cartilage that is a cushion of the knee joint. This can often be caused by twisting or direct trauma. It can lead to knee instability and make it difficult in movement.

Osteoarthritis

In knee osteoarthritis, the smooth and slick tissues become thin, rough and damaged as time passes. It can cause pain, swelling and reduce the movement. This is very common in older people. It can be treated with the pain management options, which can monitor the degradation that leads to the knee replacement.

Patellar Instability

Patellar instability leads to the dislocation of the kneecap. When the kneecap gets pushed out of its place, it can also be called subluxation. This can be caused by an injury in the knee. It can be treated by the application of pressure to move the kneecap back into its position. This can be done with knee braces for support and physical therapy for strengthening the muscles.

Prevention Tips to Avoid Knee Instability and ACL Injury

• Doing regular exercises of strengthening helps to target the quadriceps and hamstrings muscles to improve and support the knee.
• Doing stretching and flexibility exercises which helps to maintain the motion and warm up the body before doing any physical activity. So that it can protect your body from any injuries or strain.
• Avoid high-impact movement
• You should wear comfortable shoes or any footwear.
• You can use knee braces if it is needed.

Risk Factors for Knee Instability Post ACL Tear

• Surgical Timing: They delay the surgery for 12 weeks between the injury and surgery. It may be a risk factor for instability.
• Associated Ligament: It is a concomitant grade 2 medical collateral ligament (MCL) injury and meniscus tear. They increase the likelihood of the instability and this is a major factor.
• Graft Choice: In this, the use of the allograft, the donor tissue, has a higher failure rate as compared to the autograft, which is the patient’s tissue. This mostly happens in young patients.
• Patient Age: If the patients are younger or they are between 20 to 23 years old, the risk of the re-injury or instability has increased. It happens because the demand for the activities is higher and they are highly participating in the activities.
• Tunnel Positioning: Improper tunnel positioning during ACL surgery can increase the risk of graft failure and knee instability.

Diagnosis for an ACL Injury

The injury is completely proven with the clinical tests, and it clears the doubt of an ACL injury. The tests are:

• Physical Examination: A doctor will assess the knee tenderness, swelling or any other movement of the knee. In this, you should walk, bend, or move your knee to evaluate the range of motion for the areas of weakness or for instability. In this, doctors do some tests like the Lachman test and the Pivot shift test to identify the knee stability. These tests help to identify that the tibia moves to the femur and help to see any abnormal activity of an ACL injury.
• Imaging Tests (MRI, X-ray): MRI scan is used to identify the damage in the ligaments, tendons and other soft tissues in the knee. It is a common method to identify the ACL injury. MRI provides the proper detailed images of the ligament and the surrounding structures, which helps the doctor to differentiate between the partial and complete tears. To examine the fractures or bone related things, X-ray is used which contributes to instability and ligament damage.
• Functional Knee Assessment: It evaluates how the knee is performing the movement at that time. It helps to stay attentive if the conservative or surgical treatment is good enough.

When to See a Doctor?

If you have experienced any of the symptoms of knee instability and ACL injury, you must visit the doctor. The Symptoms are:

• If you are feeling locking, clicking or catching in your knee while moving or bending your knee.
• When you move your knee or twist, you would have the sensation or hear the voice of popping.
• When you are not able to bear the pain and are not able to straighten the knee.
• Pain or any symptoms stay for more than 3 days.

Conclusion

We hope that you understand everything about the knee instability after ACL injury. The rehabilitation after ACL injury treatment includes the phases of ACL, stages of the timeline recovery and the grades of the ACL injury are explained. There are also the main causes of knee instability after the ACL injury, which include sports, playing, doing activities, etc.

To prevent it, you should do exercise and stretching on a regular basis and avoid high or heavy exercise or weight lifting. The management of knee instability after ACL injury includes the methods of thr RICE, physical therapy, and knee bracing. This content is for informational purposes only and should not replace professional medical advice. So, consult with a medical expert for better treatment and care.