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Can we trust combined anteversion and Lewinnek safe zone to avoid hip prosthesis dislocation?
Alejandro Hernández1,2, Kushal Lakhani1,2, Jorge H Núñez1,2
1Hip Unit, Department of Orthopedic Surgery, University Hospital of Vall d'Hebron, Universitat Autónoma de Barcelona, Passeig de la Vall d'Hebron, 119-129, 08035, Barcelona, Spain.
Journal of Clinical Orthopaedics and Trauma
|August 26, 2021
Summary
Dislocation after total hip arthroplasty (THA) can occur even with correct combined anteversion (CA) and within the Lewinnek safe zone. Further research is needed to understand why these dislocations happen.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Radiology
Background:
- Total hip arthroplasty (THA) is a common procedure to address hip joint issues.
- Dislocation remains a significant complication following primary THA.
- Combined anteversion (CA) is a critical parameter for assessing THA stability.
Purpose of the Study:
- To investigate the association between correct combined anteversion (CA) and the incidence of hip prosthesis dislocation after THA.
- To evaluate the reliability of the Lewinnek safe zone in predicting THA stability and preventing dislocation.
Main Methods:
- A retrospective, non-interventional study analyzing 2489 primary THA cases.
- Radiographic and clinical data were reviewed for patients who experienced hip prosthesis dislocation.
- Acetabular and femoral anteversion, along with combined anteversion (CA), were assessed.
Main Results:
- In dislocated hips, acetabular anteversion was correct in 73.5% and femoral anteversion in 38.2%.
- Only 47.0% of dislocated THA had correct combined anteversion (CA).
- 32.3% of dislocations occurred despite components being within the Lewinnek safe zone and having correct CA.
Conclusions:
- Correct combined anteversion (CA) and placement within the Lewinnek safe zone do not entirely prevent THA dislocation.
- A significant percentage of dislocations occur even with optimal component positioning.
- Further investigation is required to identify additional factors contributing to THA dislocation.
