Radiographic evaluation of anterior cruciate ligament reconstruction

Radiographic evaluation of anterior cruciate ligament (ACL) reconstruction involves:

• femoral component
  • a line is drawn along the posterior cortex of the femur
  • a second line is drawn along the roof of the intercondylar notch of the femur (Blumensaat line)
  • the point of intersection of these two lines should be at the inferior portion of the femoral component of the graft
  • the angle measured between a line drawn along the femur diaphysis and the femoral tunnel angle must be approximately 39°. Angles of approximately ≤17° are associated with rotational instability
• tibial component
  • the tibial component should be entirely posterior to and parallel or more steep to and the line drawn along the roof of the intercondylar notch (Blumensaat line)
  • when the femoral tunnel is drilled through the tibial tunnel, it is recommended to drill the tibial tunnel at an angle of 65 degrees to 70 degrees in the coronal plane, tibial tunnel angle of ≥72° is associated with greater loss of flexion and anterior laxity
• tibial or femoral canal widening
  • loss of parallel walls and increase in diameter more than 2 mm from reconstruction time
• hardware complications
  • migration of Endobutton into the femoral canal
  • interposing soft tissue between Endobutton and femoral shaft 
  • migrated/displaced interference screw from the tibial or femoral canal
• proud/intramuscular screw tip 

See also

• anterior cruciate ligament
• anterior cruciate ligament tear
• cyclops lesion