- Acetabular Component Anteversion:
- see
native acetabular anteversion and
femoral anteversion
- note that it can be difficult to judge component flexion on the OR table due to patient position;
- if the patient is tilted posteriorly, there will be a tendency to ream the component in retroversion;
- in the lateral position, if the patient's pelvis is flexed relative to the torso, the surgeon the ream the
component in a retroverted position (if degree of anteversion is calculated off of patient's torso);
-
McCollum's line extends from anterosuperior iliac spine to the sciatic notch;
- this gives a reproducible landmark to help the surgeon gage the proper angle of reaming;
- generally the line of reaming and cup insertion is either perpendicular to McCollum's line or is slightly anterior to the line;
- safe rande for flexion was 20 degrees to 40 degrees;
- when cup was positioned in 20 deg flexion impingement was occasionally noticed w/ hip flexed to 90 deg & IR to 90 deg;
- to eliminate impingement of prosthetic neck against the prosthetic cup, flexion was increased to 30 degrees;
- references:
-
Anteversion of the acetabular cup. Measurement of angle after total hip replacement.
-
Influence of component positions on dislocation computed tomographic evaluations in a consecutive series of total hip arthroplasty
-
Dislocation After Total Hip Arthroplasty: Causes and Prevention.
-
Factors predisposing to dislocation after primary total hip arthroplasty.
A multivariate analysis.
-
A simplified method to determine acetabular cup anteversion from plain radiographs.
-
Accuracy of intraoperative assessment of acetabular prosthesis placement.
-
Acetabular revision for recurrent dislocations: results in 14 cases after 3 years of follow-up.
-
Dislocation After Total Hip Arthroplasty: Causes and Prevention.
