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 ~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 than 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° to 70° 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 >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