ACL Reconstruction
Learn about ACL injuries, ACL reconstruction surgery, recovery, and treatment options for adults, teenagers, and young athletes.
ACL Reconstruction
ACL injuries are among the most common knee injuries seen in active adults, teenagers, and young athletes. They often occur during sports involving twisting, pivoting, jumping, or sudden changes in direction, and can significantly affect knee stability, confidence, and return to activity.
Dr Alex Nicholls is an orthopaedic surgeon with a particular interest in ACL injuries, paediatric and adolescent sports knee injuries, and ACL reconstruction surgery.
What Is an ACL Injury?
The anterior cruciate ligament (ACL) is one of the major stabilising ligaments within the knee joint. It helps control rotational movement and prevents excessive forward movement of the shin bone relative to the thigh bone.
An ACL injury occurs when the ligament is stretched, partially torn, or completely ruptured.
ACL injuries commonly occur during:
Soccer
AFL
Basketball
Netball
Rugby
Skiing
In many cases, the injury occurs without direct contact.
Common Symptoms of an ACL Tear
Symptoms of an ACL injury may include:
A popping sensation at the time of injury
Rapid swelling within the first 24 hours
Pain and difficulty continuing sport or activity
A feeling that the knee is unstable or “giving way”
Reduced confidence during twisting or pivoting movements
Some patients may continue daily activities reasonably well but experience instability when returning to sport.
Diagnosing an ACL Injury
Diagnosis usually involves a combination of:
Clinical assessment
Physical examination
MRI imaging
An MRI scan helps confirm:
ACL tears
Meniscal injuries
Cartilage damage
Associated ligament injuries
Understanding the extent of the injury helps guide treatment planning.
Treatment Options for ACL Injuries
Treatment depends on several factors including:
Age
Activity level
Sporting goals
Knee stability
Associated injuries
Not every ACL injury requires surgery.
Non-Surgical Management
Some patients may initially be managed with:
Physiotherapy
Strengthening programs
Activity modification
Structured rehabilitation
This approach aims to improve:
Strength
Knee control
Stability
Function
Non-surgical management may be appropriate for some individuals depending on symptoms and activity demands.
ACL Reconstruction Surgery
ACL reconstruction surgery involves replacing the torn ligament using a graft to restore knee stability.
Surgery may be considered when:
The knee remains unstable
There are repeated “giving way” episodes
Returning to pivoting sport is a priority
Associated injuries are present
There are different surgical techniques and graft options depending on the individual patient.
ACL Reconstruction in Children and Teenagers
ACL injuries in younger athletes require additional consideration because growth plates may still be open.
Treatment planning takes into account:
Skeletal maturity
Remaining growth
Sporting demands
Knee stability
Dr Alex Nicholls has a particular interest in paediatric and adolescent ACL injuries and has contributed to research in paediatric ACL reconstruction and return-to-sport outcomes.
Recovery After ACL Surgery
Recovery after ACL reconstruction is gradual and structured.
Early Recovery
The initial phase focuses on:
Swelling management
Restoring movement
Walking mechanics
Protecting the knee
Rehabilitation Phase
As recovery progresses, rehabilitation focuses on:
Strength rebuilding
Balance and control
Movement quality
Functional rehabilitation
Physiotherapy is an important part of the recovery process.
Return to Sport After ACL Reconstruction
Return to sport is based on:
Strength recovery
Knee stability
Functional testing
Movement quality
Overall recovery progression
Rather than relying on a fixed timeline alone, return-to-sport decisions are guided by clinical assessment and rehabilitation progress.
Research continues to examine how young athletes recover after ACL reconstruction and how strength and movement influence safe return to activity.
Why Early Assessment Matters
An unstable ACL-deficient knee may place other structures within the knee at risk over time, including:
Meniscus cartilage
Joint cartilage
Other stabilising ligaments
Early assessment helps determine:
The extent of the injury
Whether surgery should be considered
Appropriate rehabilitation pathways
Frequently Asked Questions
Does every ACL tear require surgery?
No. Some ACL injuries can be managed with structured rehabilitation alone, depending on symptoms, stability, activity level, and sporting goals.
How long does recovery after ACL reconstruction take?
Recovery timelines vary between individuals. Rehabilitation is gradual and progression is based on strength, movement, and functional recovery rather than a single fixed timeframe.
Can children and teenagers have ACL reconstruction surgery?
Yes. ACL reconstruction can be performed in younger patients, although treatment planning differs from adults because growth plates may still be open.
When can I return to sport after ACL surgery?
Return to sport depends on several factors including strength, stability, rehabilitation progress, and functional testing.
What happens if an ACL injury is left untreated?
Some patients function well without surgery, while others experience ongoing instability that may increase the risk of further injury within the knee.
Do I need an MRI for an ACL injury?
MRI imaging is commonly used to confirm ACL tears and assess for associated injuries such as meniscal or cartilage damage.
Research & Evidence-Based Care
Dr Alex Nicholls maintains an active involvement in research relating to ACL injuries, paediatric knee surgery, return-to-sport outcomes, and sports knee surgery. His work has contributed to current understanding of ACL reconstruction and rehabilitation in younger athletes.