Vertical acetabular positioning with an inclinometer in total hip arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Surgical Technology

Background:

• Accurate vertical acetabular implant positioning is critical in total hip arthroplasty (THA).
• Current methods relying on visuospatial perception may lead to suboptimal implant placement.
• Variability in acetabular cup angles can impact surgical outcomes and implant longevity.

Purpose of the Study:

• To evaluate the efficacy of an inclinometer in achieving precise vertical acetabular implant positioning.
• To compare the accuracy and variability of acetabular cup placement using an inclinometer versus visuospatial perception.
• To determine if an inclinometer can increase the probability of placing the acetabular cup within a safe vertical angle range.

Main Methods:

• Fifty acetabular cup insertions were performed on a cadaver pelvis model.
• Cup vertical angles were measured using both visuospatial perception and an inclinometer.
• Variability and adherence to a safe angle range (40-49 degrees) were analyzed.

Main Results:

• Acetabular cup vertical angles averaged 44.4° ± 11.4° with visuospatial perception and 42.2° ± 3.8° with the inclinometer.
• 100% of cups achieved the safe angle range with the inclinometer, compared to 64% with visuospatial perception.
• The inclinometer reduced variability in cup positioning by a factor of 2.0 to 4.5.

Conclusions:

• The use of an inclinometer significantly improves the accuracy and consistency of vertical acetabular cup positioning in THA.
• An inclinometer increases the probability of achieving the desired safe vertical angle range, potentially improving surgical outcomes.
• The inclinometer is a valuable adjunct for enhancing acetabular cup insertion technique in clinical practice.