Patella Fractures

Patella Fractures

 

The Patella is the largest Sesamoid bone in the body.  The quadricep attaches to the superior portion of the patella, and at the inferior pole the patella tendon attached to the tibia at the tibial tuberosity.  Some would suggest that the patella is embedded into the quadricep tendon.  The patella transmits tensile forces from the quadricep to the tibia.  The pressure at the patella is at its greatest at 45 degrees and creates between 2 to 10 newton's per millimeter squared. 

 

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Fractures account for 1% of skeletal injuries. Fractures occur secondary to high level forces applied to the patella.  This can be from direct or indirect forces.

Direct Fractures occur from a blunt force or trauma.

  -Transverse: horizontally across the patella
  -Vertical: run from superior to inferior poles
  -Marginal: occurs at the perimeter of the patella
 -Osteochondral: cracks or discontinuities

Indirect fractures usually occur as a result of the individual being osteoporotic.  Much lower forces are required for fractures to occur when the bone is osteoporotic.  These can be twisting or violent contractions of muscle surrounding the knee

Non-operative: Fractures that have less 2 mm separation.  Non-operative treatment requires 2-6 weeks of immobilization and may be weight bearing as tolerated as early as 1 week following immobilization. In more conservative cases non-weight bearing or partial weight bearing may be necessary up to 8 weeks. 

Surgical treatment:  Patella fracture greater than 2 mm, commuted fractures, or severely osteoporotic bone.  Surgery includes wires and screws being placed along the fracture line/site.  Wires and screws are not removed post operatively unless complications occur.

X-rays are the best way to diagnose a patella fracture, but MRI or CT scan should be done if other injuries are suspected