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Cheating the Acetabular Component Horizontally in Total Hip Arthroplasty
Insights
Cheating acetabular component placement during total hip arthroplasty (THA) to achieve less than 30° abduction avoids vertical positioning and yields equivalent clinical outcomes compared to 30°-50° abduction. This technique prevents complications like dislocations and loosening.
Area of Science:
- Orthopedic Surgery
- Arthroplasty
- Biomechanical Engineering
Background:
- Inadvertent vertical positioning of acetabular components during total hip arthroplasty (THA) can occur.
- A common surgical technique involves
- cheating
- component abduction an additional 10° horizontal (goal=30°) to avoid vertical placement.
- The clinical implications of acetabular components placed in less than 30° abduction are not well-documented.
Purpose of the Study:
- To evaluate the clinical and radiographic outcomes of THA with acetabular components positioned in less than 30° of abduction.
- To compare these outcomes with components positioned between 30° and 50° of abduction.
Main Methods:
- Retrospective review of consecutive primary THA procedures performed by a single surgeon.
- Patients were grouped into cohorts based on acetabular component abduction: <30° or 30°-50°.
- Collected demographic and operative data, complications, Harris Hip Scores (HHS), and radiographic analysis.
Main Results:
- 149 hips had component abduction <30° (mean 25.8°). No components exceeded 50° abduction.
- At an average 37-month follow-up, no significant difference in HHS was observed between the two cohorts (P=.137).
- The <30° abduction cohort experienced no dislocations, component loosening, or osteolysis.
Conclusions:
- Cheating
- the acetabular component to a more horizontal position effectively prevents excessively vertical placement.
- Acetabular component abduction less than 30° demonstrates equivalent clinical outcomes to abduction between 30° and 50°.
- This technique is safe and effective in primary THA.
Abstract:
To avoid inadvertent vertical positioning of the acetabular component during total hip arthroplasty (THA), the authors routinely "cheat" component abduction an additional 10° horizontal (goal=30°). This likely increases the incidence of components placed into abduction of less than 30°, the clinical consequences of which are not well studied. The purpose of this study was to determine the clinical and radiographic outcomes in patients undergoing THA with acetabular components positioned in less than 30° of abduction as compared with those with components positioned between 30° and 50°. A retrospective review was performed of consecutive patients undergoing primary THA with horizontally cheated acetabular component position performed by a single surgeon. Patients were grouped into cohorts with either component abduction less than 30° or between 30° and 50°. Demographic data, operative data, and complications were recorded. Harris Hip Scores (HHS) and radiographic analysis were obtained from preoperative and most recent clinic visits. Between September 2004 and September 2010, 320 consecutive THA procedures were performed. A total of 149 hips had component abduction less than 30° (mean, 25.8°; range, 15.7°-29.4°). No components had greater than 50° of abduction. At an average 37-month follow-up, no significant difference in HHS was found between the 2 cohorts (P=.137). The horizontal cohort had no dislocations, component loosening, or osteolysis. By cheating the acetabular component more horizontal, an excessively vertical position was avoided. Component abduction less than 30° yielded equivalent clinical outcomes to component abduction between 30° and 50°. [Orthopedics. 2016; 39(6):e1092-e1096.].
