Courtesy: Nirav Pandya MD, Associate Professor, Chief of Paediatric Orthopaedics, University of California at San Francisco(UCSF), USA

Pediatric Anterior Cruciate Ligament Injury

Introduction

Previously considered rare in children
- Reason:
  - Ligaments stronger than bone — injuries occurred at physis or tibial spine

Current Trend

Rapidly increasing incidence

Why Increasing?

Early sports specialization (age 6–10)
High training load (20–30 hrs/week)
Seen even in 7–9-year-olds

ACL Function

Prevents:
- Anterior tibial translation (especially at ~30° flexion)
- Hyperextension
- Internal rotation

Provides:
- Rotational + sagittal stability

Bundles

Anteromedial bundle
Posterolateral bundle

Current practice:

Single bundle reconstruction

Unique Pediatric Considerations

Growth Plate (Physis)

Major growth contributor:
- Distal femur

Surgical Risks

Growth disturbance:
- Valgus deformity
- Recurvatum
- Limb length discrepancy (rare)

Natural History (Non-operative)

Earlier approach:

Delay surgery

Problems with Non-operative Treatment

Persistent instability
Meniscus tears
Early osteoarthritis (by early 20s)

Conclusion

Non-operative treatment – poor outcomes

Failure Rates

Pediatric ACL reconstruction:
- 10–25% failure
Adults:
- 3–4%

High-Risk Group

Age 12–14 years
- Most active
- Poor compliance
- Re-tear rate ~20%

Why Higher Failure in Children?

High activity level
Early return to sports
Poor rehab compliance

Growth Disturbance Risk

Overall risk:
- ~4%

Key insight:

Preventing re-tear is more important than fear of physis injury

Clinical Features

History

Acute:
- Pain + swelling
Chronic:
- “Knee instability”

Acute Hemarthrosis Causes

Age 7–12

ACL injury
Meniscus tear
Osteochondral fracture
Patellar instability (commonest non-surgical)

Adolescents

ACL injury > meniscus

Examination

Difficult due to guarding

Key Tests

Lachman test – Best to rule out
Pivot shift – Best to confirm
Anterior drawer – Less useful

Assessment of Skeletal Maturity

Do NOT rely only on age

Use

X-ray (open/closed physis)
Tanner staging
Menarche (girls)
Growth spurt history
Height vs parents

Investigations

1. X-ray (First Step)

Rule out:
- Tibial spine fracture
- Distal femur fracture

2. MRI

Confirms:
- ACL tear
- Meniscus injury
- Cartilage damage

? Tibial Spine Fracture

Classification: Meyers & McKeever

Type I – Conservative
Type II – Trial reduction
Type III – Surgery

Treatment Principles

Key Factors

Skeletal maturity
Activity level
Compliance
Growth remaining

Treatment Options

1. Non-operative

Not preferred

Leads to instability + arthritis

2. Surgical Options

Extra-articular
Physeal-sparing
Partial transphyseal
Transphyseal

Graft Choice

Preferred

Autograft

Options

Hamstring
Quadriceps tendon
BTB (only skeletally mature)

Avoid

Allograft
- 4× higher failure rate

Surgical Techniques (By Age)

Stage	Technique
Tanner 1–2	Physeal-sparing
Tanner 3–4	Transphyseal
Tanner 5	Adult reconstruction

Technical Pearls

Drill minimal physis (<7%)
Use soft tissue graft
Avoid bone plugs

Vertical tunnels:

Protect physis
BUT reduce rotational stability

Revision ACL

Re-failure rate ~20%
Poor outcomes

Golden Rule

Avoid first failure

Risk Factors for ACL Injury

Modifiable

Quadriceps dominance
Weak core
Poor neuromuscular control
Dynamic valgus

Non-modifiable

Female sex
Narrow intercondylar notch
Increased Q angle

Prevention

Neuromuscular training programs

Example

FIFA program:
- Reduces ACL injuries by ~75%

Exam Pearls (? High Yield)

Pediatric ACL injuries – increasing incidence
Non-operative – poor outcomes
Early surgery – prevents arthritis
Re-tear risk – 10–25%
Most vulnerable – 12–14 years
Growth disturbance – low (~4%)
Autograft > allograft
Prevention is critical

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