Pediatric Tibial Spine Avulsions

Dr. Garcia’s newest technique to fix ACL tibial spine using the new ACL tightrope system

Overview

• a tibial eminence fracture, also known as a tibial spine fracture, is an intra-articular fracture of the bony attachment of the ACL on the tibia that is most commonly seen in children from age 8 to 14 years during athletic activity
  • treatment is closed reduction and casting or open reduction and fixation depending on the degree of displacement and whether it can be reduced

Epidemiology

• incidence
  • 2-5% of knee injuries with effusion in the pediatric population
• demographics
  • most common in ages 8-14

Pathophysiology

• traumatic mechanism
  • rapid deceleration or hyperextension/rotation of the knee, as in sports
  • same mechanism that would cause ACL tear in adult
  • fall from bike or motorcycle (typically resulting in hyperextension)

Associated conditions

• occur in 40% of eminence fractures
  • meniscal injury
  • collateral ligament injury
  • capsular damage
  • osteochondral fracture

Prognosis

• overall prognosis is good with 85% returning to prior level of sport

Anatomy

Osteology

• tibial eminence
  • non-articular portion of the tibia between the medial and lateral tibial plateau
  • Consists of two spines: ACL attaches to medial spine
  • ACL insertion is 9mm posterior to the intermeniscal ligament and adjacent to anterior horns of meniscus
  • PCL does not attach to tibia spines

• Pediatric specific
  • Intercondylar eminence in incompletely ossified and is more prone to failure than ligamentous structures
  • Failure occurs through deep cancellous bone
  • Fracture usually confined to intercondylar eminence, but it may propagate to tibial plateau, medial is most common

Ligaments

• anterior cruciate ligament inserts 10-14 mm behind anterior border of tibia and extends to medial and lateral tibial eminence

Presentations

Symptoms

• severe swelling and pain in the knee
• inability to bear weight

Physical exam

• inspection
  • immediate knee effusion due to hemarthrosis
  • Knee usually in flexed position
• ROM
  • often limited secondary to pain
  • once pain is controlled, lack of motion may indicate
    • meniscal pathology
    • displaced/entrapped fracture fragment positive anterior drawer

Imaging

Radiographs

• recommended views
  • AP
  • lateral
    • most useful for determining fracture displacement
  • intercondylar
  • oblique
    • helpful in determining the extent of tibial plateau involvement

CT

• useful for pre-operative planning
• used when fracture displacement cannot be determined by plain radiographs

MRI

• better at determining associated ligamentous/meniscal damage than CT or radiographs
• Majority of fractures show no additional internal derangement (meniscus injuries)
  • 15-37% of cases have associated intra-articular pathology

Treatment

Non-operative

Dr. Garcia demonstrates his all suture technique for ACL repair and ACL tibial spine repair.

• closed reduction, aspiration of hemarthrosis, immobilization in full extension
  • indications
    • non-displaced type I and reducible type II fractures
  • reduction technique
    • see techniques below
  • immobilization
    • cast in extension for 3-4 weeks
      • patients get extremely stiff with prolonged immobilization
      • allows for gradual rehab program

Operative

• ORIF vs. all-arthroscopic fixation
  • indications
    • Type III or Type II fractures that cannot be reduced
      • type II fractures may fail to reduce due to the entrapped medial meniscus, entrapped intermeniscal ligament, or the pull of the lateral meniscus attachment block to extension