Paediatric femur (lateral view)

The lateral femur view for paediatrics is part of a standard series examining the femur in its entirety, including the hip and knee joint.

Indications

This view demonstrates the femur in an orthogonal position to the AP view. This allows assessment of suspected dislocations, fractures, localising foreign bodies and osteomyelitis within the long bone. Depending on departments, this view can be crucial for orthopaedic surgeons to determine the length of the femur for prosthetic purposes.

Patient position

• patient is rolled at least 45° onto the side of interest

• the unaffected leg is bent to stabilise the patient's position i.e. foot firm on the bed to ensure stability 

• to acquire the entire femur in one image, it may be necessary to place the detector in a diagonal position parallel to the femur

Technical factors

• anteroposterior projection

• centring point

  • mid femur region

• collimation

  • laterally to the skin margins

  • superior to ASIS

  • inferior to proximal third of tibia/fibula

• orientation  

  • portrait

• detector size

  • 30 cm x 43 cm

• exposure ¹

  • 63-70 kVp

  • 1.6-2.5 mAs

• SID

  • 100 cm

• grid

  • no

Image technical evaluation

• greater and lesser trochanters should be superimposed by the femoral neck

• a small part of the lesser trochanter is visible medially

• anterior and posterior margins of the femoral condyles should be superimposed

Practical points

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

Immobilisation 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 or use sandbags to keep the leg 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 utilised to avoid scattered radiation to parents and staff ³