Does Frontal Plane Rotation Really Matter In Bunions?

A few years ago at the American College of Foot and Ankle Surgeons (ACFAS) Annual Scientific Conference, I started hearing about an evolving philosophy regarding bunion deformity correction and frontal plane rotation. Frankly, I didn’t think much of it and essentially ignored the idea as just another reason to justify doing a Lapidus bunionectomy. For someone who has a very difficult time understanding how people define “hypermobility,” the frontal plane rotation conversation felt equally as esoteric.

A year later at the ACFAS conference in Phoenix, I was part of the faculty at a “pre-conference” cadaver workshop. Prior to the cadaver portion of the workshop, each faculty member gave a short presentation on his or her area of expertise for the attendees to get acclimated for the lab portion. It was during this lecture time that I had the opportunity to see Paul Dayton, DPM, MS, FACFAS, present on frontal plane deformity of bunions and why it was important. I really didn’t know Dr. Dayton prior to this lecture beyond cordial respect and greetings.

Dr. Dayton’s lecture was compelling and thought provoking. I spent a good amount of time with him during the lab discussing his philosophies and experience in treating bunions with frontal plane deformity and correction. Later that week, we went to dinner and continued the conversation. I was far from convinced as he suggested that untreated frontal plane deformity led to recurrence and/or poor results. The treatment he proposed for this deformity was fusion of the first metatarsocuneiform joint with frontal plane correction built in. As a staunch “scarf guy,” this was hard for me to accept. Despite my skepticism, Paul’s lecture and subsequent conversation opened my eyes and mind to a new concept in bunion deformity and correction. 

Over the course of the next two years, I have been paying closer attention. I now take axial sesamoid X-rays as part of my preoperative bunion workup, looking to appreciate whether the sesamoids are disarticulated from the metatarsal or are in perfect alignment but the metatarsal itself is rotated.

A critical paper in 2015 showed that in weightbearing computed tomography (CT) scans of feet with some hallux valgus deformity, the sesamoids are very much in their proper articulation with the first metatarsal but that the metatarsal itself is actually rotated.¹ This paper definitely shows that, in fact, there is frontal plane deformity with a subset of bunion deformities that we may not have previously appreciated.

Over the last couple of years, I have been a part of a bunion focus group that is evaluating the presence of frontal plane rotation and the best way to correct it.  The group consists of surgeons who essentially believe that the Lapidus is the gold standard for bunion correction and I have been placed in the group as the opposition voice. I have been in many cadaver labs with this group, observed the frontal plane rotation, the mechanics that contribute to it and listened to hours of presentations and debates on the subject.

What are my conclusions? Yes, frontal plane deformity does exist in bunion deformity and, in some cases, we need to address the deformity as part of the surgical procedure.  

While you may consider this is a small group of radical thinkers (like I did three years ago), the discussion of frontal plane rotation is becoming more prevalent at our conferences. Last summer at the American Orthopedic Foot and Ankle Society (AOFAS) annual meeting, Charles Saltzman, MD, presented his research on new concepts regarding frontal plane rotation and hallux valgus. As an aside, he failed to reference Dr. Dayton, who has made more contributions in this area than anyone and had presented his theories at the AOFAS meeting the year before. 

The ACFAS Annual Scientific Conference in February 2017 in Las Vegas has many sessions and lectures that will discuss these ideas of bunion deformity and correction. The Foot and Ankle Specialty Day Program during the AOFAS annual conference in San Diego has a large section on bunions and you can be sure the speakers will discuss frontal plane rotation in detail.

You can be sure that industry will start to pay attention as well. Right now, the Lapiplasty (Treace Medical Concepts) procedure addresses the frontal plane deformity of a bunion during a Lapidus procedure with instruments to help guide a surgeon through this triplanar correction.

For me, I still stick with the scarf procedure. However, the evidence is compelling and I have started incorporating a frontal plane derotational component of a scarf procedure to correct that aspect of the deformity when present. While I have not performed that aspect of the surgery for very long, my early results are very favorable. I am encouraged by what I am seeing with respect to correction and patient satisfaction. We have started a prospective study looking at our patient outcomes.

There are definitely naysayers out there who are resistant to change and ideas that challenge the accepted protocols. I believe we are in the midst of an evolution when it comes to the evaluation and treatment of bunion deformity. We need to open our minds to the possibilities.

The author discloses that he is a consultant for Treace Medical. To learn more about frontal plane correction and the scarf procedure, go to www.fabi2017.com and sign up for the cadaver lab on January 26, 2017.

Reference

1. Kim Y, Kim SK, Young KW, Naraghi R, Cho HK, Lee SY. A new measure of tibial sesamoid position in hallux valgus in relation to coronal rotation of the first metatarsal in CT scans. Foot Ankle Int. 2015; 36(8):944-952.