54-year-old male with unknown mechanism of injury now has knee swelling

Case
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54-year-old male with anterior pain swelling and decreased range of motion. Injured 5 days ago. No prior surgery.

Long- and short-axis fat- and water-weighted images were performed. 1.5 Tesla.

  • The extensor tendons are intact. 
  • Functional full thickness PCL tear and sprain. 
  • Pivot shift injury. ACL injury with comminuted avulsion fracture at its insertion. There are at least three major fragments which are displaced mildly rotated and distracted up to 5mm. The largest fragment measures 11 x 13mm. Grade 1 to 2 sprain of the ACL ligament itself. Comminuted minimally depressed fracture of the posterolateral tibial plateau. Small minimally depressed fracture of the lateral femoral condyle. Chondral thinning and chondral contusions noted in the lateral compartment. Small flap tears noted in the anterior and posterior horns of the lateral meniscus (series 5 images 17 and 18). 
  • Grade 2 sprain of the tibial collateral ligament with partial thickness tear of the ligament itself proximally. Deep fibers of the medial collateral complex are torn with avulsion of the meniscofemoral ligaments and mild anteromedial displacement of the anterior horn and 4cm flap tear in the posterior horn. Likely partial tear of the anterior root. 
  • Nondisplaced fracture of the posteromedial tibial plateau and grade 1 sprain of the fibular collateral and biceps femoris tendons.
  • Popliteus myotendinous junction sprain with microtears with large hematoma likely arcuate ligament injury. 
  • Capsular swelling with large hemarthrosis. 
  • No substantive patellofemoral arthrosis. 
  • Comminuted avulsion fracture of ACL full thickness tear of PCL large flap type tear of the medial meniscus (check for bucket fragment). Possible knee subluxation.
  • Pivot shift injury. Comminuted avulsion fracture at the ACL insertion. There are at least three major fragments which are displaced mildly rotated and distracted up to 5mm. Grade 1 to 2 sprain of the ACL ligament itself. Typical fractures in lateral compartment. Chondral thinning and chondral contusions noted and small flap tears noted in the anterior and posterior horns of the lateral meniscus. 
  • Grade 2 sprain of the tibial collateral ligament with partial thickness tear. Tears of the meniscofemoral ligaments and with anteromedial displacement of the anterior horn and 4cm flap tear in the medial meniscus posterior horn. Likely partial tear of the anterior root. Nondisplaced fracture of the posteromedial tibial plateau and grade 1 sprains of the fibular collateral and biceps femoris tendons consistent with contrecoup injury. 
  • Popliteus myotendinous junction sprain with microtears with large hematoma likely arcuate ligament injury. 
  • Capsular sprain and large hemarthrosis. 
  • Functional full thickness PCL tear and sprain.

Related Diagnoses

Diagnosis Definitions

ACL avulsion fracture, Medial meniscus large flap tear, Knee, MSK, PCL tear,