Review Question - QID 2970

The rugby player has sustained an injury to his anterior cruciate ligament (ACL), as demonstrated by the Segond fracture on radiograph and bone-bruising pattern on magnetic resonance imaging (MRI).

The ACL is the most commonly injured knee ligament requiring surgery, with an incidence of between 100,000 and 200,000 ruptures per year in the United States. The majority of ACL tears occur from non-contact athletic injuries. Acute ACL tears are associated with lateral meniscal tears. Physical examination findings include positive Lachman and Pivot shift tests. Imaging includes radiographs which are usually normal; however, the presence of a Segond fracture (avulsion fracture of the proximal lateral tibia) is pathognomonic for an ACL rupture and represents bony avulsion by the anterolateral ligament (ALL). MRI demonstrates bone bruising of the middle third of the lateral femoral condyle (sulcus terminalis) and posterior third of the lateral tibial plateau in more than 50% of acute ACL tears.. Bone bruise patterns correlate with the direction of the abnormal anterior translation and abutment of the posterolateral tibia against the middle third of the lateral femur during the injury. Treatment options include nonoperative management with physical therapy and lifestyle modification or operative intervention if failure of conservative measures.

Bathala et al present a radiologic case study of a Segond fracture visualized on AP radiograph of the knee of a patient who sustained an ACL rupture. They discuss the critical nature of this finding and the need for further imaging, as it is associated with ACL tears, meniscal tears, and damage to structures in the posterolateral corner.

Viskontas et al discuss different patterns of bone bruising demonstrated on MRI in acute anterior cruciate ligament ruptures of 100 patients, 86 with non-contact and 14 with contact injuries. They found that the non-contact mechanism correlates with more severe bone bruising in both the medial and lateral compartments as demonstrated on MRI.

Figures:
Figure A - AP radiograph of the knee that demonstrates a Segond fracture
Figures B and C - coronal T1 and T2 MRI slices that demonstrate bone bruising of the middle third of the lateral femoral condyle and posterior third of the lateral tibial plateau

INCORRECT ANSWERS:
Answers 1, 3, 4, 5 - Segond fracture as well as bone bruising of the middle third of the lateral femoral condyle and posterior third of the lateral tibial plateau are not associated with injuries to the PCL, popliteus, LCL, or MCL.