Patient-Specific Instrumentation

Patient-Specific Instrumentation - Tailored Tools

• Custom-made surgical guides/jigs derived from patient's preoperative CT/MRI scans.
• Aims: Enhance accuracy of implant placement, alignment, and surgical workflow.
• Workflow: Imaging → 3D reconstruction → PSI design (CAD) → 3D printing → Sterilization → Intraoperative use.
• Advantages: Precise bone cuts, potentially ↓ OR time, simplified instrumentation.
• Applications: Total Knee Arthroplasty (TKA), Total Hip Arthroplasty (THA), complex osteotomies.

⭐ PSI aims to accurately replicate the preoperatively planned component position and mechanical axis alignment.

PSI Workflow - Scan to Plan

• Goal: Create patient-matched surgical guides for precise bone cuts & implant placement.

• Sequence:

• Key Advantage: Aims for ↑ accuracy & efficiency in surgery.

⭐ PSI demonstrates improved accuracy in achieving planned component alignment in arthroplasty (e.g., TKA).

PSI Applications - Joint-Specific Solutions

• Knee Arthroplasty (TKA/UKA):
  • Patient-specific femoral & tibial cutting jigs.
  • Goal: Accurate bone resections, optimal implant alignment (mechanical axis, rotation).
  • Potential for reduced surgical time & blood loss.
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• Hip Arthroplasty (THA):
  • Custom guides for acetabular cup placement (target inclination & anteversion).
  • Assistance with femoral neck cut, stem sizing, and version.
  • Aims for accurate leg length & offset restoration.
• Shoulder Arthroplasty (TSA/RSA):
  • Glenoid-specific guides for precise component version & inclination.
  • Humeral osteotomy guides for accurate resection.
  • Enhanced baseplate screw trajectory in RSA.

⭐ PSI significantly improves the accuracy of achieving the planned component position in TKA, especially for femoral rotation and tibial slope.

PSI Pros & Cons - Gains vs. Gotchas

PSI Evidence - Proof & Potential

• Efficacy: Mixed. Some studies show ↑ alignment accuracy (TKA/THA); others find no significant clinical outcome difference vs. conventional.
• Outcomes vs. Conventional:
  • Alignment: Potential for ↑ accuracy (e.g., tibial slope, femoral rotation).
  • Operative Time: Variable; may ↓ with experience.
  • Blood Loss: Often ↓.
  • Functional Scores: Largely comparable long-term.
• Future Potential:
  • Enhanced precision in complex cases (e.g., deformities).
  • Integration with robotics & AI.
  • Cost reduction needed for wider adoption.

⭐ PSI aims to reduce outliers in component placement, potentially enhancing implant survivorship.

High‑Yield Points - ⚡ Biggest Takeaways

• Patient-Specific Instrumentation (PSI) uses custom-made surgical guides based on preoperative imaging (CT/MRI).
• Aims to enhance accuracy of bone cuts and implant placement, especially in TKA and THA.
• Facilitates precise execution of the preoperative surgical plan intraoperatively.
• Potential benefits: improved limb alignment, reduced outliers, and potentially shorter OR time.
• Reduces reliance on conventional jigs and manual referencing of anatomical landmarks.
• 3D-printed guides are a common form of PSI, translating virtual plans to reality.