The pattern of bone bruise in knee injuries (a.k.a. bone contusion) can give clues for the mechanism and associated injuries.
Radiographic features
Five classic bone contusion patterns have been described 1-4:
-
pivot-shift injury
- valgus stress to flexed and externally rotated knee
- contusion pattern: posterolateral tibial plateau and mid part of lateral femoral condyle
- associated with anterior cruciate ligament (ACL) tears
- see also: contrecoup injury of the knee, O'Donoghue unhappy triad
-
dashboard injury
- anterior force to tibia in a flexed knee (e.g. knees against dashboard in motor vehicle collision, or fall onto flexed knee)
- contusion pattern: anterior tibia +/- posterior patella
- associated with posterior cruciate ligament (PCL) tear
-
clip injury
- valgus stress to flexed knee
- contusion pattern: lateral femoral condyle and lateral tibial plateau +/- medial femoral condyle from medial collateral ligament (MCL) avulsive stress
- associated with MCL injuries
-
hyperextension injury
- direct force to anterior tibia with foot planted
- contusion pattern: "kissing contusions" of anterior tibial plateau and anterior femoral condyle
- associated with ACL, PCL, meniscal injuries, and in severe cases knee dislocation
-
lateral patellar dislocation
- twisting injury to flexed knee
- contusion pattern: anterolateral lateral femoral condyle and inferomedial patella
- associated with medial patellar retinaculum +/- medial patellofemoral ligament injury +/- medial patellotibial ligament injuries