Approach to orthopaedic X-rays

by Maritz Laubscher, Michael Held & Graham McCollum

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Basics

You can remember a simple approach an XRs through the acronym ABCS (Adequacy, Bone, Cartilage, Soft tissue).

Specific views need to be requested depending on the suspected injured joint.

Joint	Views
C-spine	AP, lateral, open mouth (dens injuries)
Shoulder	AP, Y-view, axillary view
Elbow	AP, lateral, Greenspan (radial head and neck #)
Wrist	Scaphoid views
Pelvis	AP, inlet view, outlet view
Acetabulum	AP, judet views - objurator oblique, iliac oblique
Ankle	AP, lateral, Mortise views (talar shift and syndesmotic injuries)
Foot	AP, lateral, oblique
Markers for GSWs	help understand bullet tracts
Stress views	Done by orthopod

A. Adequacy

Is this an adequate X-ray regarding demographic information of the patient, date, time, and site/side, view or projection? (e.g. AP X-ray of the right shoulder showing distal to the midshaft of the humerus and medial to past the mid clavicle but not including the sternoclavicular joint), Rule of Twos.

The Rule of Twos:

When requesting and evaluating orthopaedic X-rays, it is important to always apply the Rule of Twos:

• 2 views: Usually AP and lateral.
• 2 joints: Include the joint above and below the bone with the pathology.
• 2 limbs: Useful for comparison, particularly in children with growth plates provided the other side is normal.
• 2 opinions
• 2 occasions: PaPrticularly in fractures before and after reduction or application of splints/casts.

B. Bone

Assess from outside (cortex) to inside (medullary cavity) and trace the outline of the bone.

• Density; ‘Darker’, less distinct bone projection with thin cortices is described as osteopaenic. Lesions are described compared to the surrounding bone: Lytic = density is
• lower, sclerotic = density is higher, or a combination described as mixed.



• Fracture: Any disruption or break in the cortex should be described according to its location (diaphysis, metaphysis, epiphysis, intra or extra articular), pattern (simple or complex/ comminuted) and displacement.
• Displacement describes how the distal part of the bone has moved relative to the proximal part of the bone. The displacement should be described in at least 2 planes, the coronal plane as seen on an AP X-ray and the sagittal plane as seen on a lateral X-ray. The axial plane displacement is rotation and often needs to be assessed clinically as it is not obvious on AP and lateral X-ray. Displacement can be described as LARA (length, apposition, rotation and angulation).

  Example: The midshaft transverse tibia fracture is shifted 25% medial and 25% posterior with 10° of varus tilt and 30° of anterior tilt, there is a 5mm of impaction.

C. Cartilage/joint

Assess for joint congruency; subluxation is when the joint is partially in tact and dislocation is when there is no contact between the articular surfaces.

Assess for signs of cartilage degeneration or osteoarthritis; joint space narrowing, osteophytes, subchondral sclerosis and subchondral cysts.

S. Soft tissue

• Swelling or signs of joint effusion or haemarthrosis.
• Gas suggesting an open wound or infection.
• Foreign body, e.g. glass.
• Discontinuity of the soft tissue line or dressings, indicating a wound.