Anterior Cruciate Ligament (ACL) Reconstruction

Reconstructing the ACL to restore knee stability and support a return to movement and activity

Anterior cruciate ligament (ACL) reconstruction is a surgical procedure used to treat a torn ACL, one of the key ligaments that helps stabilise the knee joint. The ACL plays an important role in controlling forward movement and rotational stability of the knee. When it is injured, the knee may feel unstable, particularly during activities that involve pivoting, turning, or sudden changes in direction.

ACL injuries commonly occur during sport or high-demand activities, but can also result from falls or other trauma. Not all ACL injuries require surgery, and treatment depends on factors such as your symptoms, activity level, and overall knee function.

A thorough assessment is important to determine whether ACL reconstruction may be appropriate for your individual condition, goals, and lifestyle.

What is ACL reconstruction surgery?

ACL reconstruction surgery is a procedure used to treat a torn anterior cruciate ligament (ACL), one of the key ligaments that helps stabilise the knee. The ACL connects the thigh bone (femur) to the shin bone (tibia) and plays an important role in controlling forward movement and rotational stability of the knee. When the ACL is torn, the knee may feel unstable, particularly during activities that involve pivoting, turning, or sudden changes in direction. Because the ACL has a limited ability to heal on its own, reconstruction is often performed rather than repair.

The procedure involves:

Replacing the torn ligament with a graft, which may be taken from your own tendon (such as the hamstring or patellar tendon) or, in some cases, from a donor source
Positioning the graft within the knee to replicate the function of the original ligament

Over time, the graft integrates with the surrounding tissue and functions as a new stabilising ligament.

The aim of ACL reconstruction is to restore knee stability and support return to activity, although outcomes can vary depending on factors such as your activity level, associated injuries, and rehabilitation.

When ACL reconstruction may be recommended

ACL reconstruction surgery may be considered when a torn anterior cruciate ligament (ACL) is causing knee instability, reduced function, or difficulty returning to activity. Not all ACL injuries require surgery. In some cases, symptoms can be managed with physiotherapy and activity modification, particularly if the knee remains stable during everyday activities.

ACL reconstruction may be discussed when:

The knee feels unstable or gives way, especially during pivoting or change of direction
You wish to return to sport or higher-demand activities that place stress on the knee
There is persistent instability despite rehabilitation
You have associated injuries, such as meniscal tears or other ligament damage
Your knee symptoms are affecting daily activities or confidence in movement

The decision to proceed with surgery depends on a combination of your symptoms, activity goals, knee stability, and overall joint condition.

Preparing for ACL reconstruction surgery

Preparing for ACL reconstruction surgery involves a combination of clinical assessment, physical preparation, and practical planning to support a smooth procedure and recovery. Before surgery, Dr Scott Tulloch will undertake a comprehensive evaluation of your knee, which may include:

A detailed clinical examination
Imaging, such as MRI and X-rays, to assess the ACL and identify any associated injuries (for example, meniscal or cartilage damage)

You will also receive pre-operative instructions, which may include guidance on:

Fasting prior to surgery
Managing or temporarily stopping certain medications
Preparing for your hospital admission
Organising crutches or a knee brace for use after surgery

Prehabilitation (pre-surgery physiotherapy) is often recommended to help optimise your knee before surgery. This may focus on:

Improving range of motion, particularly achieving full extension
Reducing swelling
Strengthening the quadriceps and surrounding muscles

Optimising your general health may also support recovery. This can include maintaining a healthy weight, stopping smoking, and managing any underlying medical conditions. It is also important to prepare your home environment for your return after surgery, including arranging support if needed, ensuring a safe walking space, and planning for reduced mobility in the early stages.

What happens during ACL reconstruction surgical procedure?

ACL reconstruction surgery is performed to restore stability to the knee after a torn anterior cruciate ligament. The procedure is typically carried out under general anaesthesia or regional anaesthesia (such as a spinal anaesthetic), so you will be comfortable throughout.

Surgical technique
ACL reconstruction is usually performed using keyhole (arthroscopic) techniques, which involve small incisions and the use of a camera to visualise the inside of the knee.

During the operation:

Small incisions are made around the knee to insert a camera (arthroscope) and specialised instruments
The torn ACL is assessed, and any associated injuries (such as meniscal or cartilage damage) may be addressed
A graft is prepared, which may be taken from your own tendon (commonly the hamstring or patellar tendon) or, in some cases, from a donor source
Tunnels are carefully created in the femur and tibia to position the graft in the correct anatomical location
The graft is secured within the knee using fixation devices, allowing it to function as a new ligament

Once the graft is in place, the knee is assessed for stability and range of motion. The incisions are then closed and dressed, and you will be transferred to recovery for monitoring.

Duration
Surgery typically takes around 1 to 2 hours, depending on the complexity of the injury and whether additional procedures are required. Over time, the graft integrates with the surrounding tissue and functions as a new stabilising ligament. Dr Scott Tulloch will explain your individual surgical plan and graft options, helping you understand what to expect from your procedure.

Understanding the risks and considerations

All surgical procedures carry potential risks, and ACL reconstruction surgery is no exception. Understanding these risks and considerations can help you make an informed decision about your care.

General risks associated with surgery may include:

Infection
Bleeding
Blood clots (deep vein thrombosis or pulmonary embolism)
Reactions to anaesthesia

There are also considerations specific to ACL reconstruction. These may include:

Persistent knee pain or stiffness
Reduced range of motion, particularly difficulty fully straightening or bending the knee
Graft failure or re-injury, especially with return to high-demand activity
Instability, if the graft does not function as intended
Donor site symptoms, if a tendon graft is taken from your own body (such as discomfort at the hamstring or patellar tendon)
Nerve irritation or numbness around the incision sites, which is usually temporary

In some cases, additional procedures or revision surgery may be required if symptoms persist or further injury occurs. Recovery and outcomes can vary depending on factors such as your activity level, associated injuries, graft choice, and adherence to rehabilitation.

What to expect after ACL reconstruction surgery

Recovery after ACL reconstruction surgery is a structured and progressive process, focused on protecting the graft, restoring movement, and gradually returning to activity.

Hospital stay
ACL reconstruction is often performed as a day procedure, meaning many patients return home the same day. In some cases, an overnight stay may be recommended depending on your individual circumstances.

Pain management
It is common to experience pain, swelling, and stiffness in the early stages. These symptoms are managed with:

Medications prescribed by your care team
Cold therapy (ice) to reduce swelling
Elevation of the leg to support circulation

Assistive devices and mobility
You will usually begin mobilising soon after surgery, often on the same day with guidance from a physiotherapist.
Crutches are typically used in the early recovery period to support walking and reduce load on the knee. A knee brace may be recommended in some cases.

Discharge instructions
Before leaving hospital, you will receive guidance on:

Wound care and dressing management
Managing pain and swelling
Weight-bearing and activity restrictions
Recognising signs of complications

Early movement is encouraged, with exercises aimed at restoring range of motion and muscle activation, particularly in the quadriceps. Recovery progresses over time, with gradual improvement in mobility, strength, and confidence. The pace of recovery can vary depending on your injury, surgical approach, and response to rehabilitation.

Rehabilitation and recovery after ACL surgery

Rehabilitation following ACL reconstruction is a structured, staged process aimed at protecting the graft while restoring movement, strength, and knee stability.

Early phase (first few weeks)
The initial focus is on:

Reducing pain and swelling
Regaining full knee extension and improving gentle flexion
Activating the quadriceps muscles
Beginning walking with crutches, progressing as advised

A structured physiotherapy program begins soon after surgery, with close guidance to ensure safe progression.

Intermediate phase (weeks to months)
As healing progresses, rehabilitation focuses on:

Improving range of motion
Rebuilding strength, particularly in the quadriceps and hamstrings
Enhancing balance and movement control

Activity levels are gradually increased, with exercises tailored to your progress and functional goals.

Later phase (return to higher-level activity)
Rehabilitation continues with:

Advanced strength and conditioning
Sport-specific or activity-specific training, where appropriate
Gradual return to running, pivoting, and higher-demand movements under guidance

Recovery timeline
Recovery after ACL reconstruction typically progresses over several months. Many patients return to light activities within a few months, while return to higher-demand sport may take 9–12 months or longer, depending on individual progress.

It is important to follow a graduated rehabilitation program, as returning to activity too early may increase the risk of re-injury. Ongoing participation in physiotherapy and maintaining strength and conditioning are important for long-term knee function.

Long-term outcomes after ACL reconstruction

Long-term outcomes following ACL reconstruction are influenced by factors such as your activity level, associated knee injuries, graft type, and commitment to rehabilitation. Many patients experience improved knee stability and function, which may allow a return to daily activities and, in some cases, sport. The aim of the procedure is to restore confidence in the knee and support controlled movement, although outcomes can vary between individuals. Over time, the graft used to reconstruct the ACL undergoes a process of biological integration, functioning as a new stabilising ligament within the knee.

It is important to understand that:

Recovery and return to activity timelines can vary
There is a risk of re-injury, particularly with higher-demand sports
Some patients may experience ongoing symptoms, such as stiffness or occasional discomfort
There may be an increased risk of degenerative changes in the knee over time, especially if there are associated injuries

Maintaining strength, flexibility, and neuromuscular control through ongoing exercise and physiotherapy may help support long-term knee function.

Regular follow-up and appropriate rehabilitation are important to monitor progress and guide safe return to activity.

Dr Scott Tulloch will provide ongoing guidance to support your recovery and help you achieve the best possible long-term outcome based on your individual circumstances.