Cheating the Acetabular Component Horizontally in Total Hip Arthroplasty

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.