ACL injuries are becoming increasingly common in children and teenagers participating in organised sport. Sports involving pivoting, jumping, twisting, or sudden changes in direction — such as soccer, netball, basketball, rugby, and AFL — place significant stress on the knee and can increase the risk of ACL injury in younger athletes.

Managing ACL injuries in children and adolescents differs from managing the same injury in adults. One of the key considerations is skeletal maturity, which refers to whether a child’s growth plates are still open.

Dr Alex Nicholls has contributed to research examining skeletal maturity assessment in paediatric ACL reconstruction and the factors that influence treatment planning in younger patients.

What Is an ACL Injury?

The anterior cruciate ligament (ACL) is one of the main stabilising ligaments in the knee. It helps control rotational movement and stability during activities such as running, jumping, and changing direction.

When the ACL is torn, the knee can become unstable, particularly during sport or high-level activity.

Why Are ACL Injuries Different in Children and Teenagers?

Children and adolescents are still growing, which means their bones contain growth plates (physes). These growth plates are areas of developing tissue near the ends of bones.

When planning ACL reconstruction surgery in younger patients, surgeons must consider:

• Remaining growth

• Skeletal maturity

• Risk to growth plates

• Long-term knee stability

• Future sporting goals

This makes treatment planning more complex than in fully grown adults.

Common Symptoms of a Teenage ACL Injury

Symptoms of an ACL injury in children or teenagers can include:

• A popping sensation at the time of injury

• Rapid swelling of the knee

• Difficulty continuing sport or activity

• Instability or “giving way” episodes

• Reduced confidence in the knee

Some younger athletes may initially continue participating in sport before ongoing instability becomes more obvious.

How Is an ACL Injury Diagnosed?

Diagnosis generally involves:

• Clinical assessment

• Physical examination

• MRI imaging

MRI scans are particularly useful for confirming:

• ACL tears

• Meniscal injuries

• Cartilage damage

• Bone bruising

Assessment also helps determine skeletal maturity and guide treatment planning.

What Is Skeletal Maturity?

Skeletal maturity refers to how much growth a child or teenager has remaining.

This is important because:

• Growth plates remain open in younger patients

• Surgical techniques may need modification

• Treatment decisions may differ depending on maturity level

Assessing skeletal maturity helps determine the safest and most appropriate surgical approach.

Does Every Teenage ACL Injury Need Surgery?

Not always.

Some patients may initially be managed with:

• Physiotherapy

• Strengthening programs

• Activity modification

• Structured rehabilitation

However, recurrent instability can increase the risk of additional damage to:

• Meniscus cartilage

• Joint cartilage

• Other stabilising structures of the knee

Treatment decisions are individual and depend on:

• Age

• Activity level

• Sporting goals

• Degree of instability

• Associated injuries

What Is Paediatric ACL Reconstruction?

Paediatric ACL reconstruction is surgery performed to restore knee stability while taking growth plates into consideration.

The procedure involves replacing the torn ACL using a graft.

Different surgical techniques may be used depending on:

• Skeletal maturity

• Remaining growth

• Anatomy

• Activity demands

The aim is to restore stability while minimising risk to growth areas.

Recovery After ACL Reconstruction in Teenagers

Recovery after paediatric ACL surgery is gradual and structured.

Early Recovery

The initial focus is on:

• Swelling management

• Restoring movement

• Protecting the knee

Rehabilitation Phase

Rehabilitation progresses toward:

• Strength rebuilding

• Balance and control

• Movement quality

• Sport-specific training

Return to Sport

Return to sport is guided by:

• Strength testing

• Functional movement assessment

• Knee stability

• Overall recovery progress

Recovery timelines vary between individuals.

Why Early Assessment Matters

ACL injuries in children and teenagers should be assessed carefully, particularly in active young athletes.

Ongoing instability can sometimes lead to additional injury within the knee over time. Early assessment helps determine:

• The extent of the injury

• Whether growth plates are involved

• Appropriate management options

• Whether surgery should be considered

Current Research in Paediatric ACL Surgery

Research in paediatric ACL reconstruction continues to evolve, particularly around:

• Skeletal maturity assessment

• Growth plate-safe surgical techniques

• Return-to-sport outcomes

• Long-term knee health in younger athletes

Dr Alex Nicholls has contributed to published research examining skeletal maturity assessment in paediatric ACL reconstruction.

Summary

ACL injuries in children and teenagers require careful assessment and individualised treatment planning. Because younger athletes are still growing, factors such as skeletal maturity and growth plates play an important role in decision-making.

Management may involve structured rehabilitation alone or ACL reconstruction surgery depending on the degree of instability, sporting demands, and associated injuries.

This article is based in part on Dr Alex Nicholls’ published research in paediatric ACL reconstruction and skeletal maturity assessment.

Read the full publication:
Skeletal Maturity Assessment in Pediatric ACL-Reconstruction