A method to calculate the acetabular cup anteversion after total hip replacement based on 3D coordinate system
- 1 Department of Orthopedics, Huxi Hospital (Shanxian Central Hospital), Jining Medical University, Jining, China
- 2 Department of Orthopedics, Huxi Hospital (Shanxian Central Hospital), Jining Medical University, Jining, China
- 3 Department of Orthopedics, Huxi Hospital (Shanxian Central Hospital), Jining Medical University, Jining, China
- 4 Department of Orthopedics, Huxi Hospital (Shanxian Central Hospital), Jining Medical University, Jining, China
- 5 Department of Orthopedics, Huxi Hospital (Shanxian Central Hospital), Jining Medical University, Jining, China
- 6 Department of Orthopedics, Huxi Hospital (Shanxian Central Hospital), Jining Medical University, Jining, China
Abstract
Aim: To explore an accurate method to calculate acetabular cup anteversion after total hip arthroplasty. Method: 1) A 3D coordinate system was established with the center of the hip joint rotation center base as coordinate center. The acetabular exit plane and Pettersson formula acetabular anteversion and Riten Pradhan formula acetabular anteversion and acetabular true anteversion were drawn; 2) Determine the mathematical expression of Pettersson formula acetabular anteversion α and Riten Pradhan formula acetabular anteversion β in the coordinate system. The true acetabular anteversion is projection angle of Pettersson formula acetabular anteversion α on cross-section in the presence of acetabular abduction δ , determining mathematical expression of the acetabular anteversion θ by trigonometric functions. Results: Real acetabular cup anteversion θ = arctg (tg β /cos δ ). Conclusion: The true acetabular cup anteversion and Pettersson formula anteversion and Riten Pradhan for mula anteversion were quite different. The difference was increased with the acetabular cup abduction angle increased. The formula was simple and accurate and worthy of clinical reference.
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