ACL Tear & Injuries: Causes, Symptoms, and Recovery

The anterior cruciate ligament (ACL) is one of the key stabilisers of your knee, but it’s also one of the most commonly injured ligaments. Whether you're an athlete or simply enjoy staying active, understanding ACL injuries is essential for protecting your mobility and overall joint health. Especially if you're planning a winter sports holiday, where common ski injuries like ACL tears are prevalent, it’s vital to be informed about prevention and recovery. 

What is the ACL?

The anterior cruciate ligament (ACL) is one of the main ligaments in your knee, connecting your thigh bone (femur) to your shin bone (tibia). It helps keep your knee stable, especially during activities like running, jumping, or quickly changing direction. If the ACL is injured, it can make it hard to move around and affect your everyday life.

Common causes of ACL injuries

ACL injuries are common in sports and physical activities that place stress on the knee joint. They typically occur due to one of the following factors:

1. Sudden stops or changes in direction

   • Sports like soccer, basketball, and football often require quick, sharp pivots or abrupt stops. These sudden movements can put excessive strain on the knee, increasing the likelihood of an ACL tear.

2. Landing from jumps

   • Improper landing techniques, such as landing with your knees unaligned or too straight, can put significant pressure on the ACL. This is a common cause of injury in activities that involve frequent jumping, like volleyball or basketball.

3. Direct contact or trauma

   • A direct hit to the knee, such as during a football tackle or a collision in sports, can force the knee to bend or twist unnaturally, leading to an ACL injury.

4. Overuse and wear

   • Overuse and wear refer to the repetitive movements or constant strain on the knee joint, often seen in high-intensity training or endurance sports, which can gradually weaken the ACL over time. This makes the ligament more prone to injuries, even during less intense activities.

Symptoms of ACL injuries

Recognizing an ACL injury can be challenging, but common symptoms like sudden pain, swelling, instability, limited knee movement, and a popping sensation are key indicators to watch for. The following are detailed explanations of the most common symptoms to help you understand what to look out for:

1. Sudden pain

   • An ACL injury often begins with a sharp, intense pain in the knee. This pain typically occurs immediately at the time of the injury and can be severe enough to stop any activity, such as running or playing sports. The pain may persist or subside slightly but often intensifies with movement.

2. Popping sensation

   • Many individuals with an ACL tear report hearing or feeling a distinct "pop" in the knee at the moment of injury. This sensation is often described as a sudden snapping or popping sound, which is a hallmark indication that the ligament has been damaged.

3. Swelling

   • Swelling in the knee joint is one of the earliest signs of an ACL injury. This swelling is caused by blood and fluid accumulating in the joint due to damage to the ligament and surrounding tissues. It can appear within a few hours after the injury and may cause the knee to feel tight, warm, and tender to the touch.

4. Instability

   • A torn ACL compromises the knee's ability to remain stable, as the ligament is a primary stabiliser. This can lead to a sensation of the knee "giving way" or feeling wobbly, especially when trying to walk, climb stairs, or bear weight on the injured leg. This instability often becomes more noticeable with sudden movements or changes in direction.

5. Limited range of motion

   • After an ACL injury, the knee joint often stiffens, making it difficult to fully extend or bend the knee. This restriction in movement can result from swelling, pain, or mechanical interference caused by the torn ligament or other associated injuries, such as damage to the meniscus.

Experiencing a combination of the above symptoms? Think that you might have torn your ACL? Request for an appointment with our specialists at Thomson Medical today for an accurate diagnosis and a personalised treatment plan.

How are ACL injuries diagnosed?

Diagnosing an ACL injury requires a combination of clinical evaluation and imaging tests:

1. Physical examination

   • Healthcare providers assess knee stability, swelling, and range of motion.

   • Tests like the Lachman test and pivot-shift test are performed to evaluate ligament integrity and knee instability.

2. Imaging tests

   • MRI: Used to confirm the extent of the ACL tear and check for related injuries, such as damage to the meniscus or cartilage.

   • X-rays: Performed to rule out fractures or other bone injuries that may occur with an ACL injury.

Treatment of ACL injuries

The treatment for an ACL injury depends on factors such as the severity of the tear, the patient’s age, activity level, and overall health. Treatment options generally fall into two categories: non-surgical and surgical. 

Non-surgical treatment

Non-surgical approaches may be suitable for partial tears or cases where the knee remains stable:

1. Rest and activity modification

   • Reducing or avoiding activities that stress the knee helps alleviate pain and prevent further damage.

2. RICE method

   • Rest: Refrain from activities that aggravate the knee.

   • Ice: Apply ice packs for 15–20 minutes every few hours to reduce swelling.

   • Compression: Use an elastic bandage or knee brace for support and to control swelling.

   • Elevation: Keep the knee elevated to minimise fluid buildup.

3. Physical therapy

   • A structured rehabilitation programme focusing on strengthening muscles, improving flexibility, and restoring balance is essential.

   • Exercises aim to regain range of motion and stabilise the knee, while a physical therapist may teach proper techniques to prevent re-injury.

4. Medication

   • Over-the-counter pain relievers such as ibuprofen or paracetamol can help reduce pain and inflammation.

Surgical treatment

Surgical reconstruction is often necessary for completely torn ACLs or unstable knees, especially in active individuals:

1. ACL reconstruction surgery

   • The damaged ligament is replaced with a graft, either from the patient’s own body (autograft) or a donor (allograft).

   • Common graft options include:

     • Hamstring tendon

     • Patellar tendon

     • Quadriceps tendon

2. Procedure and recovery

   • Surgery is typically performed arthroscopically, involving small incisions and a camera for precision.

   • Recovery time varies but typically includes several months of intensive rehabilitation to restore knee strength, mobility, and function.

At Thomson Medical, our orthopaedic specialists deliver comprehensive, tailored care designed to meet each patient's unique needs. Request for an appointment today to receive expert consultation and treatment for ACL injuries, with a focus on ensuring the best possible recovery and a smooth return to activity. 

Post-surgery rehabilitation: a step-by-step guide to ACL recovery

Recovering from ACL surgery requires a structured rehabilitation program designed to restore knee function, build strength, and gradually return to normal activities. Here’s an overview of the key stages in post-surgery rehabilitation:

1. Early rehabilitation

   • The initial phase focuses on reducing swelling and restoring range of motion in the knee. Gentle exercises, such as controlled stretches and mobility work, are introduced. Patients may need crutches to avoid putting too much weight on the knee during this stage.

2. Strengthening exercises

   • As healing progresses, targeted exercises are added to strengthen the quadriceps, hamstrings, and other supporting muscles. Building strength in these areas helps stabilise the knee and protect it from further injury.

3. Functional training

   • This phase involves sport-specific or activity-based exercises to prepare the knee for the demands of regular movement. These exercises mimic the motions required in sports or daily life, helping the patient regain confidence and functionality.

4. Return to activity

   • A gradual return to physical activities, including sports, is critical to avoid re-injury. With proper guidance from healthcare professionals, most individuals can resume pre-injury levels of activity within 6 to 12 months, depending on their progress and adherence to the rehabilitation plan.

FAQ

How common are ACL injuries?

ACL injuries are relatively common, especially among athletes participating in sports that involve jumping, sudden cutting movements, or rapid direction changes.

Is it possible for an ACL tear to heal on its own?

An ACL tear cannot fully heal on its own due to a lack of blood supply; partial tears may improve with therapy, but complete tears often require surgery for recovery.

Can ACL injuries be prevented?

Although not all ACL injuries can be avoided, engaging in conditioning programmes that focus on strengthening muscles, improving flexibility, and practising proper landing techniques can significantly reduce the risk.

What are the treatment options for a torn ACL?

Treatment depends on the severity of the tear and may include rest, physical therapy, or surgical reconstruction to restore ligament function in more severe cases.

How long does recovery take after ACL surgery?

Recovery typically takes 6 to 12 months, depending on the extent of the injury, the individual’s health, and their commitment to following a structured rehabilitation programme.

Will I be able to return to sports after an ACL injury?

With proper rehabilitation, most individuals can return to their pre-injury sports and activity levels, though some may need to modify their participation based on the injury and recovery progress.

What happens if an ACL injury is left untreated?

Without treatment, an injured ACL can lead to chronic instability, further damage to the knee (such as meniscus tears), and long-term joint issues like arthritis.

How soon should an ACL tear be repaired?

ACL repair is generally recommended within a few weeks of the injury, once the swelling has reduced and range of motion has been restored, to ensure optimal recovery. Delaying treatment could increase the risk of further damage to the knee. Request an appointment with Thomson Medical to consult with our specialists for a timely evaluation and a personalised treatment plan tailored to your needs.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice, please consult a specialist at Thomson Medical. Book an appointment with Thomson Medical today.