Radiographic evaluation of anterior cruciate ligament reconstruction

Last revised by Dr Henry Knipe on 09 Nov 2021

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 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° 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

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Cases and figures

  •  Case 1 : showing assessment of femoral component
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  • Case 2: normal post ACL reconstruction AP
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  • Case 2: normal post ACL reconstruction lateral
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  • Case 3: migration of ACL graft fixation screws
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