Radiography

Sequential conventional radiography is the most common, cost effective and reliable imaging modality for patients with total knee arthroplasty. Initial baseline studies are obtained either portably in the recovery room or non portably in the radiology department before discharge. Baseline radiographs serve as reference radiographs for comparisons of all future studies. Follow-up studies are usually obtained at yearly intervals or when symptoms warrant.

Standard views include:

  • Immediate postoperative portable exam
    • AP
    • Lateral
  • Follow-up study
    • AP both knees weight bearing
    • Lateral of post-surgical knee, weight bearing and cross table supine

All serial follow-up radiographs are obtained with the same positioning method to facilitate accurate comparison.

Fluoroscopy can be used when interfaces are not adequately visualized. Although standard positioning and technique are performed during conventional radiography, the central x-ray beam may not be perfectly perpendicular to components. Beam angulation that is only 15 degrees off the perpendicular axis of the component may obscure interfaces as large as 5 mm due to overlap of the prosthesis.6 Under fluoroscopic guidance, the knee is rotated to optimal position and spot films are obtained.

Lateral radiograph and fluoroscopic spot films with improved visualization of the interfaces about the femoral component.

 

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