Authors of chapter

Authors

Daniel Rikli, Michael Blauth, Samir Mehta, Franz Seibert

Editors

Michael Baumgaertner, Markku T Nousiainen

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Intraoperative imaging of the proximal femur

1. Introduction

Fluoroscopic visualization of anatomical fracture reduction and correct implant placement for the proximal femur can be significantly facilitated using the following views:

  • AP view of the proximal femur
  • Axial view of the proximal femur
  • Lateral view of the proximal femur

The lateral view does not correctly reflect the implant position in the head-neck fragment. An axial view is therefore necessary.

AO teaching video

Intraoperative Imaging of the Proximal Femur

Daniel Rikli provides insight on tips and tricks in intraoperative imaging of the proximal femur. (21 minutes)

2. AP view of the proximal femur

Positioning for optimal view

  • The beam is placed perpendicular to the femoral shaft and the coronal plane
  • The leg is internally rotated with the patella facing upward
Patient and C-arm position to obtain an AP view of the proximal femur

Verification of optimal view

The optimal view is obtained when:

  • Trochanteric area is in the center of the screen
  • Both the femoral head (including the hip joint) and shaft are visible
AP view of a trochanteric fracture

Anatomical landmarks and lines

In the AP view of the proximal femur (here with a trochanteric fracture), the following landmarks and lines can be observed:

  1. Femoral head
  2. Femoral neck
  3. Medial line
  4. Lesser trochanter
  5. Greater trochanter
  6. Femoral shaft
  7. Intertrochanteric line (anterior) superimposed with the intertrochanteric crest (posterior)
Anatomical landmarks and radiological lines in the AP view of the proximal femur and hip joint

What can be observed

  • Varus or valgus malalignment
  • Rotational malalignment
  • Translational displacement
  • Correct guide-wire insertion
AP view of the proximal femur to confirm correct guide-wire insertion in the femoral neck and head for intramedullary nailing
  • Correct implant positioning
AP view of the proximal femur to confirm correct position of a short intramedullary nail

3. Axial view of the proximal femur

Positioning for optimal view

  • The beam track should avoid the contralateral hip
  • A hemilithotomy position of the patient, scissoring, or abduction of the contralateral leg may be helpful to optimally place the C-arm
  • The beam is rotated externally by approximately 15° off the coronal plane
Patient and C-arm position to obtain an axial view of the proximal femur
  • The beam is positioned 30°–45° to the longitudinal axis of the injured leg
Patient and C-arm position to obtain an axial or lateral view of the proximal femur

Verification of optimal view

The optimal view is obtained when:

  • Centered image showing head, neck, and proximal end of shaft
  • Head-neck axis is in line with the femoral shaft (within the range of 170° and 190°)
  • Contralateral hip is not obstructing the view
In an optimal axial view, the head-neck and femoral shaft axis are aligned

Anatomical landmarks and lines

In the axial view of the proximal femur, the following landmarks and lines can be observed:

  1. Lesser trochanter
  2. Greater trochanter
  3. Femoral head
  4. Posterior line
  5. Anterior line
  6. Capsule insertion (intertrochanteric line)
Anatomical landmarks and radiological lines on an axial view of the proximal femur

What can be observed

  • Quality of reduction
  • Head-neck and shaft axis alignment
  • Correct guide-wire insertion
Axial view of the proximal femur with a guide wire positioned for nail insertion
  • Acceptable implant positioning (center-center)
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4. Lateral view of the proximal femur

The lateral view shows the anteversion of the head and neck.

Positioning for optimal view

  • The beam track should avoid the contralateral hip
  • A hemilithotomy position of the patient, scissoring, or abduction of the contralateral leg may be helpful to optimally place the C-arm
Patient and C-arm position to obtain a lateral view of the proximal femur
  • The beam is positioned horizontally, 30°–45° to the longitudinal axis of the leg and in the coronal plane
Patient and C-arm position to obtain an axial or lateral view of the proximal femur

Verification of optimal view

The optimal view is obtained when:

  • Centered image showing head, neck, and proximal end of shaft
  • Normal anteversion between head-neck axis and femoral shaft is visible
  • Trochanteric area is centered in image
  • Contralateral hip is not obstructing the view
AP view of the proximal femur

Anatomical landmarks and lines

In the lateral view of the proximal femur (here with a trochanteric fracture), the following landmarks and lines can be observed:

  1. Greater trochanter
  2. Femoral head
  3. Posterior line
  4. Anterior line
  5. Capsule insertion (part of the intertrochanteric line)
Anatomical landmarks and radiological lines in the lateral view of the proximal femur

What can be observed

  • Quality of reduction
  • Anteversion

The lateral view is not optimal to confirm implant position (eg, center-center of neck screw/blade).

Lateral view of the proximal femur with an intramedullary nail

5. Cases

Case 1

AP and lateral views showing the neck-shaft angle and the anteversion

AP and lateral views showing the neck-shaft angle and the anteversion

External rotation of the C-arm of approximately 15° from the horizontal (coronal plane) towards the AP view results in an axial view.

Patient and C-arm position and axial view of the proximal femur

AP and axial views are used to confirm center-center position of the blade in the femoral head-neck axis after nail fixation.

Note that these correct views can only be obtained with acceptable reduction of the fracture.

AP and axial views to confirm center-center position of the blade in the femoral head-neck axis after nail fixation

Case 2

This case of a pertrochanteric fracture is fixed with intramedullary nailing.

The AP and lateral views are used to confirm reduction.

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Correct guide-wire insertion through the tip of the greater trochanter is confirmed on the AP view.

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The axial view confirms correct placement of the guide wire through the greater trochanter into the medullary canal of the femoral shaft.

The axial view confirms correct placement of the guide wire for intramedullary nailing through the greater trochanter into the medullary canal of the femoral shaft.

This AP view confirms correct guide-wire insertion for the helical blade (center of the head).

AP view of the proximal femur to confirm correct guide-wire insertion for the helical blade (center of the head) of an intramedullary nail

Only the axial view (right image) gives reliable information of the guide-wire position in the head-neck fragment (center of the head).

Axial and lateral view of the proximal femur with guide-wire inserted for the helical blade of an intramedullary nail

AP view to confirm correct implant position

AP view of the proximal femur confirming correct nail position

Lateral and axial view of the same case

Lateral and axial view of a pertrochanteric fracture stabilized with an intramedullary nail
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