Exploring Applications of 3D Implants in Foot and Ankle Surgery

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3D implants are an exciting prospect for foot and ankle surgery. Years ago, when the talus in a Charcot patient had dissolved, crumbled, or displaced, I would use a femoral head allograft. And that worked out well. It helped me restore the length to the leg, but there are times when that graft would resorb and collapse. Now with the 3D implants that no longer happens. We can get our measurements from the CT scan, the engineers can design that implant that takes the place of the body of the talus. Now this implant is made, usually made out of titanium, and it can be just a round sphere to replace the body of the talus, or it can have a navicular component to it. But either way, this does not resorb with appropriate fixation. And usually this is an IM nail right through the implant.

This results in very good stability to the implant. Now a variation of this has been the ability to replace a navicular that is damaged and from previous injury and it has avascular necrosis and it cannot be salvaged. In the past I would use usually allogenic bone graft, and we had the same problem with that. It can dissolve, but now we can have a custom-made 3D titanium implant that we insert into the area of the navicular. I've used this type of technology on both a distal tibial, non-union. And we had one case,  last year, where orthopedics had tried twice to repair this non-union in the distal tibial metaphysis. And I thought, what could I do different? Certainly if I did conventional surgery, I had no better chance of getting that non-union to heal than they had.

But, we had a custom 3D implant made. I resected the non-union site and put the implant in and fused his ankle and he's done well. And I've done the same thing for non-union of the fibula as well. Also, we've been using him for brachymetatarsia in the past. I've used both allogenic bone and autogenous bone, and I've seen both of them at times resorb. I've used distraction techniques. Maybe it's, it's worked here and there, but not consistently in my hands. But this, uh, metallic 3D printed implant, uh, lengthens the metatarsal, it does not collapse, and it's done very well.

I think the most important thing would be looking at the Charcot deformities, the loss of bone in particular. When a section of bone or one bone is completely resorbed or damaged or collapsed, consider using a titanium 3D printed implant to replace that bone rather than autogenous or allogenic bone graft. And you can use an external fixator. You can use an IM nail to fuse the subtalar joint in the ankle, but the end result is that these implants seem to work very well. I've even used them on occasion on total ankle replacements that have failed, because of patient activity, falling, breaking the tibia and I've put the 3D implant in to fuse the ankle when nothing else would be able to salvage the procedure and a below-knee amputation was in the future.

But these are all custom 3D implants. Each implant is made specifically to that patient. So if we're putting in a total talus, because the talus is collapsed, we'll get a CT of the opposite extremity and then they can get measurements off of that extremity and they know what height and width to make this titanium implant in.