Authors of section

Executive editor

Michael Baumgaertner


Michael Huo, Michael Leslie, Iain McFadyen

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Supine position with knee flexed 90°

1. Introduction

This position is useful for revision knee replacement surgery.

Supine position knee flexed 90 degrees

2. Preoperative preparation

  • Verify site and side of fracture with the patient along with the type of operation planned
  • Ensure that the operative site has been marked by the surgeon
  • Condition of the soft tissues (fracture open or closed)
  • Implant to be used (note: plate comes in right and left versions)
  • Patient positioning
  • Details of the patient (including a signed consent form and appropriate antibiotic and thromboprophylaxis)
  • Comorbidities, including allergies

3. Anesthesia

This procedure is performed with the patient under general or regional anesthesia.

If a spinal anesthetic is used, the surgeon and anesthetist need to be confident that the procedure will not last more than 1.5 hours.

4. Prophylactic antibiotics

Antibiotics are administered according to local antibiotic policy and specific patient requirements.

5. Patient and x-ray positioning

  • Place the patient supine on a radiolucent operating table.
  • Place the opposite leg supine on the operating table to allow easier access for the image intensifier.
  • Ensure that soft tissues, skin pressure points, and the subcutaneous nerves (ulnar nerve at the elbows and peroneal nerve of the opposite knee) are well protected.
  • Adjust the operating table to the appropriate height and place the image intensifier on the opposite side of the injury, approaching the knee from the medial aspect.
  • Before preparing and draping, ensure adequate imaging of the femur from the hip joint to the knee in the AP and lateral views.
  • If the fracture extends proximally the use of a tourniquet may not be possible.
Supine position knee flexed 90 degrees

6. Skin disinfecting and draping

Maintain light manual traction (the assistant may need to stand on a stool) on the limb during preparation to avoid excessive deformity at the fracture site.

Disinfect the whole leg from the hip including the foot with the appropriate antiseptic.

Skin disinfecting
  • Drape the limb with a single-use U-drape. A stockinette covers the lower leg and is fixed with tape.
  • Drape the leg to allow it to be freely moved.
  • Flex the knee to 90° over a bolster.
  • Drape the image intensifier.

7. Operating room set-up

The surgeon and ORP stand on the side of the affected limb. The assistant usually stands on the opposite side to the surgeon and moves out of the way when the image intensifier is positioned.

When needed, the image intensifier is placed on the opposite side of the injury and the display screen in full view of the surgical team and the radiographer.

Operating room set-up
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