An additively manufactured locking fixation system for potential application in patient-specific implants

Area of Science:

• Biomaterials Engineering
• Additive Manufacturing
• Orthopedic Implants

Background:

• Patient-specific implants offer tailored solutions for complex orthopedic cases.
• Current manufacturing processes for implants with integrated features can be time-consuming and costly.
• There is a need for efficient methods to incorporate functional systems like locking holes directly into implants.

Purpose of the Study:

• To introduce a novel technique for integrating a locking hole system into additive manufactured (AM) patient-specific implants.
• To eliminate the need for post-processing steps like mechanical machining.
• To assess the feasibility and performance of AM-integrated locking systems.

Main Methods:

• A commercial locking system was digitally replicated using high-resolution X-ray computed tomography (CT).
• 316L stainless steel specimens were additively manufactured using laser powder bed fusion (L-PBF) in various orientations.
• Specimens underwent heat treatment to optimize mechanical properties for the locking system's function.
• Accuracy was verified through nominal/actual comparisons of printed holes.
• System strength was evaluated by measuring screw-out force.

Main Results:

• The accuracy of the additively manufactured holes was confirmed.
• Heat-treated 316L stainless steel samples demonstrated performance comparable to commercial locking systems.
• Successful integration was achieved across different build orientations, indicating robustness.
• The developed method avoids additional post-processing steps.

Conclusions:

• A novel technique enables direct integration of locking hole systems into AM implants.
• This method reduces manufacturing time and cost, enhancing implant accessibility.
• The integrated system demonstrates comparable strength to commercial counterparts, suitable for compromised bone conditions.