Acetabular cup placement is important for 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 cup 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.