Acetabular cup appropriate placement is important to determinate the implant stability and longevity. The malposition of acetabular cups negatively influences prosthesis survival and it will only lead to an increasing dislocation rate.
A study published by healio tried to determine the role played by the 3D templating in obtaining accurate acetabular component placement in total hip arthroplasty.
In this computed tomography-based study, the authors identified 93 patients who underwent primary total hip arthroplasty with computer-assisted navigation. Using the 3D templating the acetabular component at an inclination of 40° and anteversion of 20°.
The classification of the acetabular cup coverage by bone, was used as a clock face with the center of the transverse acetabular ligament and the analysis revealed that 72% of cups were uncovered between 9 to 1 o’clock for the right hips and 88% of the cups were uncovered between 11-to 3 o’clock for the left side. 74% of cups had a 1-o’clock position at the most lateral aspect. Further analysis revealed that 46% of acetabular cups had a teardrop at the same level of the most inferior aspect of the cup. 37% of cups had a teardrop above the inferior aspect of the cup. The acetabular component was aligned with the TAL in 76% of hips, retroverted to the TAL in 16% and anteverted to the TAL in 8%.
On this study, the researchers used 93 patients who underwent primary Total Hip Arthroplasty from May 2014 to May 2015. All THA procedures were performed using a posterior approach. The software uses 3D modeling of the patient’s hip, reconstructed from computed tomography (CT), which allows for pre-operative planning, optimization of component and real-time adjustments intraoperatively. The measuring parameters for THA has been validated in several studies.
Electronic medical records were used to obtain patient’s baseline characteristics including: gender, laterality, preoperative diagnosis and surgical procedures.
The study conclude that acetabular cup positioning is a critical component in THA that affects long-term THA survivorship. New robotic and computer navigation technology have helped improve the accuracy and consistency for implantation of the acetabular component.