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Updated: Aug 26, 2026
Individualized Stem-positioning in Calcar-guided Short-stem Total Hip Arthroplasty
Published on: February 27, 2018
Influence of component positions on dislocation: computed tomographic evaluations in a consecutive series of total
Takashi Nishii1, Nobuhiko Sugano, Hidenobu Miki
1Department of Orthopaedic Surgery, Osaka University Medical School, Suita, Japan.
Insights
Low cup anteversion in total hip arthroplasty is linked to posterior dislocation. Surgeons should carefully consider cup anteversion to reduce the risk of hip dislocation after surgery.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Radiology
Background:
- Total hip arthroplasty (THA) is a common procedure to address hip joint degeneration.
- Postoperative dislocation remains a significant complication following THA.
- Optimizing component positioning is crucial for hip stability.
Purpose of the Study:
- To investigate the correlation between component positions and the occurrence of postoperative dislocation in THA.
- To identify specific component parameters, particularly cup anteversion, associated with posterior dislocation.
Main Methods:
- Computed tomography (CT) was used to evaluate component positions in a series of THA patients.
- A consecutive series of THA cases using a posterolateral approach without capsular repair were analyzed.
- Correlation between cup and stem anteversion and postoperative dislocation was assessed.
Main Results:
- Hips with posterior dislocation demonstrated significantly lower cup anteversion compared to those without dislocation.
- A high percentage (78%) of dislocated hips had cup anteversion below 20 degrees.
- This association was observed irrespective of stem anteversion.
Conclusions:
- Cup anteversion is a critical factor influencing the risk of posterior dislocation after THA.
- Compensating for high femoral neck anteversion by intentionally positioning the cup at low anteversion may increase dislocation risk.
- Careful consideration of cup anteversion is essential for improving THA outcomes and reducing dislocation rates.
Abstract:
Component positions in a consecutive series of total hip arthroplasty through a posterolateral approach without capsular and external rotator repair, using the same prosthesis type, head size, and liner, were evaluated using computed tomography, and correlation with occurrence of postoperative dislocation was assessed. The 9 hips with posterior dislocation had significantly lower cup anteversion than the 181 hips without dislocation. Seven (78%) of the 9 hips with posterior dislocation had cup anteversion <20 degrees, irrespective of stem anteversion. These findings suggest that among variables of component positions, cup anteversion is one of the important factors for risk of dislocation, and that intentionally placing the cup at low anteversion to compensate for high femoral neck anteversion may predisposes the hip to postoperative dislocation.
