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.
- 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
| Feature | Gains (Pros) | Gotchas (Cons) |
|---|---|---|
| Accuracy | ↑ Implant precision, alignment; custom fit | Potential registration errors; imaging quality dependent |
| Efficiency | Potentially ↓ OR time, ↓ blood loss, fewer instruments | Learning curve; extensive pre-op planning time |
| Cost | ↑ Initial cost (guides, software, imaging); accessibility | |
| Radiation | ↑ CT exposure for pre-operative planning | |
| Complexity | Aids severe deformities, revision arthroplasty | Manufacturing lead time; not universally applicable |
| Outcomes | Improved kinematics; potentially ↑ implant longevity | Mixed evidence on clear long-term superiority vs. standard |
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.
Unlock the full lesson and continue reading
Signup to continue reading this lesson and unlimited access questions, flashcards, AI notes, and more
