Foot and ankle surgeon Dr. Canon Cornelius discusses his experience using DynaNail with minimally invasive techniques—and what other surgeons should know before trying it themselves.

Before this case, what was your experience with DynaNail and MIS, and what gave you the confidence to bring them together?

I was fortunate to receive training that emphasized both complex reconstruction and minimally invasive techniques. My experience with TTC nailing was shaped early on, while most of my MIS experience developed during fellowship, where we routinely applied MIS principles beyond straightforward forefoot cases.

Ultimately, there’s an element of taking the leap. In my experience, the best way to build comfort with minimally invasive techniques is to start applying them, then open the joint when needed to assess and refine the approach. That process reinforces learning and builds confidence over time.

A systematic method is essential—especially for joint preparation. Whether the case is open or minimally invasive, I approach each joint surface in defined quadrants and work through them deliberately to ensure thorough, balanced preparation.

In trauma cases, the inherent instability of the ankle—often evident on imaging—can make joint access easier. When working with native joints, particularly the subtalar joint, I find it helpful to first open the joint gently with a freer to understand the natural motion and anatomy. Using a low-risk instrument allows you to feel the joint’s path. From there, the burr can simply follow the same trajectory.

That progression—understanding the anatomy first, then applying the technique—was key for taking this case on.

What stood out most to you about the patient’s recovery?

The recovery was evident very quickly. This patient had been bedbound for weeks, yet she stood with physical therapy the day after surgery. At her two-week follow-up, her primary concern was that she had very little pain—which may sound surprising, but is telling. Fractures and instability are painful, and in her case, the ankle had been hurting even at rest. Stabilizing the joint eliminated that instability-related pain.

A systematic method is essential—especially for joint preparation.

Traditionally, we trade instability pain for incisional and approach-related pain, which can be significant in large reconstructions. By using a minimally invasive approach, we reduced that tradeoff—minimizing soft-tissue pain while addressing the underlying instability.

Functionally, she was able to stand early, though she initially couldn’t step up onto a curb, which is why we don’t yet have weight-bearing films. When I went in expecting to encourage her, she pointed out that she couldn’t step up onto a curb even before the injury. In that sense, we’d already returned her to baseline. While she’s still rebuilding strength after a period of prolonged bed rest, she’s progressing well with therapy and has been very pleased with the overall outcome.

Were there any differences in healing alignment or patient mobility compared to an open approach?

The biggest difference is in soft-tissue healing. From a bony standpoint, the biology doesn’t change—you’re still waiting for fusion—but I have more confidence in the skin and wound environment with a minimally invasive approach. Much of the immobilization and non–weight-bearing we worry about isn’t for construct stability; it’s to protect soft tissue. Reducing that burden can meaningfully affect recovery.

That said, minimally invasive surgery doesn’t eliminate risk. Wound issues and infection can still occur, particularly in patients with comorbidities, and thermal injury from burring is always a consideration. I do believe those risks are lower with MIS, but not zero.

Alignment, however, is non-negotiable. Just as with minimally invasive fracture fixation, there’s no excuse to accept anything less than the alignment you would demand in an open case. If adequate reduction can’t be achieved with MIS, the correct move is to convert to an open approach. I was fully prepared to do that here. MIS should never come at the expense of excellent alignment.

After seeing these results, how do you envision using this approach in future cases?

Much like how we approach fragility hip fractures, the priority in elderly ankle fractures is early mobilization. While this concept hasn’t yet been adopted as broadly in foot and ankle surgery as in hip fractures, the literature around acute TTC nailing for unstable bi- and trimalleolar ankle fractures in elderly patients is growing. Most of that work comes from the trauma literature and often doesn’t involve formal joint preparation—certainly not through a minimally invasive approach.

For me, this technique is best suited for elderly patients who have difficulty mobilizing and are at risk of becoming bedbound. It’s important to be clear that this is not a replacement for open reduction and internal fixation. Preserving motion is preferable when possible, but if a patient cannot safely mobilize, the downstream risks of immobility—pressure injuries, thromboembolic events, and medical decline—can outweigh those concerns. In patients with significant comorbidities, that balance shifts.

These cases aren’t elective; they present acutely in the hospital setting and often require timely decision-making. Being comfortable with this approach means being available in trauma settings and prepared to intervene when these patients present—particularly in situations where prolonged bed rest might otherwise be the default.

When it comes to MIS joint preparation, what details or nuances make the biggest difference?

Joint dynamics matter during preparation. The subtalar joint is relatively stable, so when you’re working in the posterior facet, you can be confident you’re preparing the surface that will ultimately fuse. From there, I work anteriorly toward the angle of Gissane and sinus tarsi, removing bone as needed.

The ankle joint is different. Because it’s more dynamic, it’s easy to over-focus on areas that appear adequate when the foot is held in plantarflexion. If you don’t deliberately work distally toward the talar neck, you may find—once the ankle is dorsiflexed into its final fusion position—that the most critical surfaces weren’t fully prepared.

One additional option is to use the existing portals to introduce a scope and directly visualize the joint. That can provide reassurance without extending the incision. I didn’t do that in this case, as the preparation appeared adequate based on alignment and radiographic bony apposition, but it’s a useful tool for surgeons early in their MIS learning curve.

For surgeons interested in trying this approach for the first time, what advice would you offer as they get started?

The foundation is mastering placement of the DynaNail itself—ideally through cadaver work or sawbones—and understanding the construct from an open perspective before layering in MIS techniques.

The more challenging aspect is joint preparation. While most surgeons are comfortable with reduction and manipulation, MIS joint prep requires trust in the technique. I recommend practicing in cadavers: perform the preparation minimally invasively, then open the joint to evaluate it. The next step is applying the technique clinically and then confirming the preparation.

From a biologic standpoint, I prefer to irrigate after the initial cartilage removal to clear debris, then return with a larger burr. This helps remove any remaining cartilage while creating a favorable fusion surface and local bone graft. In my experience, that preparation works well with DynaNail’s ability to compress and stabilize the fusion site.

Dr. Cornelius is a paid consultant at Enovis.