Executive Editor: Chris Colton

Authors: Florian Gebhard, Phil Kregor, Chris Oliver

Patella Extraarticular avulsion fracture

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Glossary

General considerations

Lower pole avulsion fractures-nonarticular. These generally occur in adolescents, or young adults. Occasionally, a thin shell of bone may be avulsed from the distal patella together with the patellar tendon (“sleeve” fracture). This may be subtle on the radiographs. A clue to the injury may be found by detection of a high-riding patella (patella alta).

Displaced fractures, especially with patella alta, require surgical fixation.

Salvage techniques
Indication summary Skill Equipment
Distal fragment too fragmented to repair Highly experienced and skilled surgeon Simple surgical and imaging resources

Avulsion patellar fractures should be considered for open operative reduction and internal fixation. However, some comminuted patellar fractures cannot be reduced openly and can only be treated with some form of salvage technique.

Indications

  • Displaced fractures which are associated with inability to actively extend the knee
  • Patella alta

Contraindications

  • Polytrauma patient in extremis
  • Medically unfit for surgery
  • Local soft-tissue compromise

Advantages

  • Restoration of extensor function
  • Early mobilization of knee joint

Disadvantages

  • Prominent metalwork after fixation
  • May need later revision of partial patellectomy to total patellectomy
  • Risk of nonunion
  • Risks of open operation
Sleeve fracture fixation
Indication summary Skill Equipment
Sleeve fracture with impaired extensor function Some specialized surgical experience Simple surgical and imaging resources

Avulsion patellar fractures should be considered for open operative reduction and internal fixation.

These fracture types occur when a shell of bone is avulsed from the distal patella. The age group comprises adolescents or young adults. This fracture type is biomechanically equivalent to patellar tendon rupture.

Indications

  • Displaced fractures which are associated with inability to actively extend the knee
  • Patella alta

Contraindications

  • Polytrauma patient in extremis
  • Medically unfit for surgery
  • Local soft-tissue compromise
  • Severe osteoporosis

Advantages

  • Restoration of extensor function
  • Early mobilization of knee joint
  • No plaster, or prolonged splintage

Disadvantages

  • Implant prominence and irritation
  • Cerclage wire to secure sleeve fractures will frequently break once knee has been fully mobilized
  • Risks of open operation

Suture repair
Indication summary Skill Equipment
Distraction with impaired extensor function Some specialized surgical experience Simple surgical and imaging resources

Avulsion patellar fractures should be considered for open operative reduction and internal fixation.

These fracture types occur when a shell of bone is avulsed from the distal patella. The age group comprises adolescents or young adults. This fracture type is biomechanically equivalent to patellar tendon rupture.

Indications

  • Displaced fractures which are associated with inability to actively extend the knee
  • Patella alta

Contraindications

  • Polytrauma patient in extremis
  • Medically unfit for surgery
  • Local soft-tissue compromis

Advantages

  • Restoration of extensor function
  • Early mobilization of knee joint
  • No plaster, or prolonged splintage

Disadvantages

  • Risks of open operation
*Skill
Basic surgical experience, no specialized skills Basic surgical experience, no specialized skills
Some specialized surgical experience Some specialized surgical experience
Highly experienced and skilled surgeon Highly experienced and skilled surgeon
*Equipment
Basic equipment only Basic equipment only
Simple surgical and imaging resources Simple surgical and imaging resources
Full specialized surgical and imaging resources Full specialized surgical and imaging resources

v1.0 2008-12-03