Ankle (weight-bearing AP view)

Last revised by Weiling Tan on 4 Apr 2023

The weight-bearing AP view of the ankle is a specialized projection that places the joint under normal weight-bearing conditions.  The projection is utilized to assess the joint under stress and better demonstrate structural and functional deformities. 

This projection is utilized to assess the structural integrity of the ankle joint. If the patient is able, weight-bearing views should be performed in acute and follow up settings 1

Other indications include:

In addition, this view can show bony diseases or lesions of the distal lower leg, talus and proximal fifth metatarsal.

Ultimately the radiographer will determine if the projection is safe to perform.

  • the patient is standing on an upright stand with the ankle in question central and perpendicular to the detector (toes facing the x-ray tube)
  • there is no rotation, the foot is in a neutral rotation 
  • the patient is distributing weight evenly 
    • have something for the patient to hold onto, especially if they unsteady on their feet
  • anteroposterior projection
  • centering point
    • the midpoint of the lateral and medial malleoli
  • collimation
    • laterally to the skin margins
    • superior to examine the distal third of the tibia and fibula
    • inferior to the proximal aspect of the metatarsals
  • orientation  
    • portrait
  • detector size
    • 24 cm x 30 cm
  • exposure
    • 50-60 kVp
    • 3-5 mAs
  • SID
    • 100 cm
  • grid
    • no
  • grid
    • no
  • the distal fibula should be slightly superimposed the distal tibia (>10mm)
  • the lateral and medial malleoli of the distal fibula and tibia are in profile
  • the tibiotalar joint space should be open, yet the full mortise joint should not be visualized on the AP

Although this projection is helpful to assess lower limb injuries better, it must be performed safely. Explain and demonstrate to the patient how it is performed. Give them something to hold on to. If the exam does not feel safe, explore alternative methods such as a standard, supine projection.

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