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Acetabular Component Position

DiscussionTHRV1A

  • restoration of normal hip center in acetabular reconstruction encourages restoration of normal biomechanics;
  • placing the socket laterally creates increased joint reactive force, and placing it directly superior requires the use of a long neck prosthesis to restore abductor moment arm;
  • long neck prosthesis will develop increased lateral bending stresses, adapting to the activities of daily living;
  • acetabular component must be positioned in anatomic position at level of true notch to reduce stresses and increase longevity;

acetabular component abduction / inclination »

acetabular component anteversion »

component dislocation »

ROM

Surgeon Related Error

References

Case Example

  • 35-year-old male w/ near anklyosed hip following a GSW to the hip;
  • preoperative films appeared to indicate that little or no medialization was necessary;
  • postoperative films, however, indicate that the cup was lateralized (hence, reaming was inadequate);
  • in retrospect, the radiographs which are rotated externally (like an iliac oblique) tend to falsely minimize the necessary amount of medialization where as X-rays which are rotated internally (like an obturator oblique), tend to over-estimate the necessary amount of medialization

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