When Accuracy and Certainty Are Not Enough on Their Own

How 3D Planning Took a PAO from Planned to Executed - Dr. Alejandro Marquez-Lara, North Carolina, USA

Periacetabular osteotomy is one of the most demanding procedures in hip preservation surgery. The acetabulum must be freed through a series of precise cuts, repositioned to an exact correction, and fixed in that position. Each step conditions the next. A drift at repositioning carries through to fixation. There is no good place to recover it.

Dr. Marquez-Lara has worked with us on PAO before. This was not a first attempt. It was a case where the workflow was pushed further, each component designed to close the gap between what is planned and what actually happens in the operating room.

Encoding the correction into the guide

The resection guide was designed so its geometry carries the planned correction. The aligning K-wires only become parallel when the mobile fragment reaches its exact planned position. Not approximately. Exactly.

Before validation, Dr. Marquez-Lara asked to visualize the correction on the full pelvis and femur model. The screw trajectories had to work for him anatomically. They did. That review step is not a formality. It is the moment where the surgeon takes ownership of the plan before the first incision.

Holding position. Fixing without improvising.

Once the fragment is repositioned, the aligner holds it. No manual pressure, no position maintained by feel. The screw guide, connected directly to the aligner, then pre-drills each fixation trajectory at depths engraved on the instrument. No approximation possible at either step. That is the design intent.

What happened after surgery

Dr. Marquez-Lara reported a significant reduction in radiation exposure during fixation. When trajectories are pre-drilled with a dedicated guide, the need for repeated fluoroscopic checks decreases considerably.

He also identified improvements for the next case. That is exactly the kind of feedback that refines the workflow over time. A collaboration that progresses case by case, not one that resets each time.

What was decided before surgery is what happened in the operating room.

3D-Side designs patient-specific surgical guides for complex orthopedic cases. Case performed by Dr. Alejandro Marquez-Lara, hip preservation surgeon, North Carolina, USA.