Pediatric knee (lateral view)

The lateral knee view for pediatrics is one of two views in order to examine the knee joint, patella, distal femur and proximal tibia and fibula. Depending on the child's age and the departmental protocol, additional views such as the skyline and intercondyler views may also be performed. In trauma situations, the horizontal beam lateral knee view is ideal for assessing joint effusions.

Indications

This projection demonstrates the knee orthogonal to the AP knee view. It is useful in diagnosing fractures, soft tissue effusions and joint space abnormalities in pediatric patients.

Patient position

• the patient is positioned in a lateral recumbent position with the unaffected leg rolled anteriorly

• lateral aspected of the affected knee in contact with the detector

• affected knee is flexed slightly ≈ 30°

Technical factors

• mediolateral projection

• centering point

  • 1.5 cm distal to the apex of the patella

• collimation

  • anteroposteriorly to the skin margins

  • superior to include the distal femur

  • inferior to include the proximal tibia/fibula

• orientation

  • landscape

• detector size

  • 18 cm x 24 cm

• exposure ¹

  • 50-60 kVp

  • 1-2 mAs

• SID

  • 100 cm

• grid

  • no

Image technical evaluation

The medial and lateral condyles of the distal femur are superimposed to indicate no rotation. There should be slight imposition of the fibular head with the tibia and an open patellofemoral joint space ². A physical metal marker is ideal for pediatric imaging. 

Practical points

Preparing the room beforehand (setting up the detector, exposure and preparing lead gowns) is important as pediatric patients may not remain still when their affected knee is moved onto the detector. 

Immobilization techniques

It is important for the radiograph to be free from motion artifact and rotation to avoid repeated x-rays.

• it may be necessary for the parent or radiographer to hold the patient in position

• ideally the parent should be in the child's direct line of sight

• techniques will vary based on the department

• distraction techniques can be utilized to avoid scattered radiation to parents and staff ³