Knee series

Last revised by Andrew Murphy on 23 Mar 2023

The knee series is a set of radiographs taken to investigate knee joint pathology, often in the context of trauma. It usually comprises an AP and lateral projection, although other non-standard, modified projections can be used for specific indications.

See also knee radiograph (an approach).


Knee radiographs are indicated for a variety of settings including 1,2:


Standard projections
  • AP view

    • demonstrates the distal femur, proximal tibia/fibula and the patella in the AP position

    • ideal projection to assess the tibial plateau and tibiofemoral alignment  

  • horizontal beam lateral view

    • orthogonal projection to the AP, routinely done in trauma horizontal beam to better demonstrate any joint effusions

    • ideal projection to assess lipohemarthrosis

    • used to examine the location of the patella and the patency of the patella tendon

Additional projections
  • rolled lateral view

    • often performed on bed-bound patients with suspected arthritis

    • orthogonal view of the AP projection

    • demonstrate the joint space, yet sacrifices any assessment of fluid levels

  • skyline (Merchant view)

    • superior-inferior projection of the patella; this is an ideal projection for patients that are better suited in the supine position

  • skyline (Laurine view)

    • inferior-superior projection of the patella; this projection is best suited to patients able to maintain a semi-recumbent position on the examination table

  • knee AP weight-bearing view

    • often used in the context of orthopedic appointments to obtain images of the knees in their natural anatomical position

  • knee intercondylar view

    • view utilized to demonstrate intercondylar space, often used for OA and suspected tibial plateau fractures 

  • Rosenberg's view

    • weight-bearing projection used to assess joint space-related pathology such as osteoarthritis 

  • oblique view

    • two views (internal and external) better demonstrating the knee joint in the absence of CT 

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