Hallux Valgus And Frontal Plane Deformity: Why Are Some Surgeons Still Not Getting It?

The research continues to pour in but there are still those who refuse to accept the change in the understanding of hallux abducto valgus (HAV) pathomechanics. The arguments against HAV as a three-dimensional deformity with a frontal plane component are hyperbole at this point.

The most recent article on the topic by Campbell and colleagues examined the frontal plane component of hallux valgus using weightbearing radiographs, weightbearing computed tomography (CT) scans and 3D computer-aided design (3DCAD) imaging.¹ Detractors of the literature on the frontal plane component of HAV (specifically Kim, Collan and their respective coworkers) complain that the findings of both studies were based on calculations from 2D CT scans.^2,3 The use of 3DCAD allows for 3D reconstruction based on magnetic resonance imaging (MRI) or CT, thereby providing a well-documented method to evaluate bony orientation.^4-8 The parameters of this study adequately mitigate the doubters’ criticisms of previous studies.

Once and for all, we can put this issue to bed. As the article stated, “HV is clearly 3D.”¹

The authors demonstrated the HAV radiographic angle measurements (hallux valgus angle and intermetatarsal angle) were consistent with measurement taken with CT and 3DCAD.¹ The average pronation angle of the first metatarsal in the HAV group was 27.3 degrees in comparison to the average of 19.1 degrees in the control group. The statistically significant difference in pronation of the first metatarsal was 8.2 degrees.

When evaluating the amount of pronation in the first metatarsal in the HAV group in this study in comparison to other studies, consistency in results is evident. Dayton and colleagues demonstrated an average of 22.1 degrees of varus rotation was required to correct the frontal plane component of HAV.⁹ Kim and coworkers found the average pronation angle for the HAV group and control group in their study to be 21.9 degrees and 13.8 degrees respectively (both consistent with a study by Campbell and coworkers).² The study also examined the pronation of the hallux in both groups with the HAV group having a statistically significant amount of pronation 12.9 degrees in comparison to the control group’s -1.6 degrees.¹ As the authors stated, “Clinically, this means that HV feet differ from normal feet not only in 2D HV and IM angles but also in the degree of first metatarsal and great toe pronation.”¹ In addition, no correlation existed between first metatarsal and hallux pronation.

Additionally, no correlation occurred between first metatarsal and hallux pronation, “suggesting that one must independently assess both the great toe and first metatarsal if both values are needed.”¹ This finding makes sense because the hallux follows the sesamoids via the plantar plate. Kim and colleagues demonstrated sesamoid subluxation to be a separate and identifiable component.²

So, what does all this information mean? No, you do not always have to do a Lapidus procedure but you should try to utilize triplanar corrective procedures. My favorites are the Bosch/SERI (simple, effective, rapid, inexpensive) procedure, the first metatarsophalangeal joint (MPJ) arthrodesis, the Lapidus bunionectomy and the Promo™ Triplanar Hallux Valgus Correction System (Paragon 28). These procedures allow triplanar correction. I do more first MPJ arthrodesis than anything for HAV correction, followed closely by the Bosch/SERI procedure. However, translational osteotomies (like the Austin or Scarf) do not allow for triplanar correction. Those unwilling to let go of the Austin or scarf achieve full deformity correction between 2.4 and 12.7 percent of the time.²

Congratulations but patients deserve better.

Kim and coworkers’ study found that 87 percent of the HAV group displayed pronation of the first metatarsal and 71.7 percent exhibited some degree of sesamoid subluxation.² The sesamoid subluxation number is eerily similar to the 73 percent recurrence rate for the Austin bunionectomy as Pentakainen and colleagues demonstrated.¹⁰ These numbers should be similar because Pentakainen and colleagues defined recurrence based on the hallux valgus angle. If the sesamoids are subluxed, eventually the hallux will follow. It is important to remember the Pentakainen study by far has the longest follow-up (7.9 years) of any study on the Austin bunionectomy.¹⁰

Why do those adamant about continuing to employ the Austin or scarf bunionectomy procedures ignore the data? Why do they try to spin outdated literature to support antiquated notions? It beats me.

Matthews ad colleagues recently argued that radiographic findings after hallux valgus surgery have little to do with patient satisfaction.¹¹ This article’s follow-up time was slightly over one year so I am not too sure what information we can truly glean from these results. I know when a patient entrusts me to correct his or her HAV deformity, both of us expect the toe to be straight afterward. Pain and motion are more important in overall satisfaction rates, but position matters. Looking a postoperative patient with a recurrent HAV deformity in the eye is not pleasant. I have done it.

The Lapidus procedure has a place in the correction of HAV deformity but not every HAV needs a Lapidus. Shocking as it may sound, even a “hypermobile” HAV deformity does not always need a Lapidus. The Lapidus procedure is not without complications.

An excellent new article by Barg and colleagues reviewed 229 studies published over 49 years (1968-2016), encompassing a total of 16,273 surgical procedures on 12,866 patients.¹² The postoperative dissatisfaction rate with the Lapidus was the fourth worst of all procedures at 10 percent, had the second highest incidence of intraoperative nerve injury at 5 percent, had the highest rate of postoperative infection at 11.4 percent, had a non-union rate of 3.77 percent (highest of all procedures reviewed), had the highest rate of reoperation not related to hardware removal at 6.6 percent and had a 6.4 percent hardware removal rate. Several studies have described the role of deformity correction in stabilization of the first ray and that first ray instability is a multilevel pathology.^13-17

As Campbell and colleagues noted: “In conclusion, our study reiterates that pronation is an important factor in the morphology of (hallux valgus) and seeks to quantify pronation as an absolute measure of the (hallux valgus) pathology … Corrective osteotomies must consider the triplanar (hallux valgus) deformity, which includes great toe and first metatarsal pronation.”¹

I find it interesting how evidence-based research has rightfully become the focus in foot and ankle surgery, but on this topic, there are those unwilling to accept the change. This is nothing new as Perera and coworkers describe the 10 steps in the formation of HAV.¹⁸ Step 7 is pronation of the metatarsal head. I believe much of the confusion on this topic is reference point-related, terminology-related and biomechanical hypothesis.

Regardless of the root cause to those still digging in their heels, either we practice evidence-based medicine, or we practice biomechanical hypotheses. I will choose evidence-based surgical research every day and twice on Sunday.

Dr. DeHeer is a speaker for Paragon 28.

References

1. Campbell B, Miller MC, Williams L, Conti SF. Pilot study of a 3-dimensional method for analysis of pronation of the first metatarsal of hallux valgus patients. Foot Ankle Int. 2018; 1071100718793391.
2. Kim Y, Kim JS, Young KW, et al. A new measure of tibial sesamoid position in hallux valgus in relation to the coronal rotation of the first metatarsal in CT scans. Foot Ankle Int. 2015; 36(8):944-952.
3. Collan L, Kankare JA, Mattila K. The biomechanics of the first metatarsal bone in hallux valgus: a preliminary study utilizing a weight bearing extremity CT. Foot Ankle Surg. 2013; 19(3):155-161.
4. Camacho DL, Ledoux WR, Rohr ES, et al. A three-dimensional, anatomically detailed foot model: a foundation for a finite element simulation and means of quantifying foot-bone position. J Rehabil Res Dev. 2002; 39(3):401-410.
5. Grood ES, Suntay WJ. A joint coordinate system for the clinical description of three-dimensional motions: application to the knee. J Biomech Engin. 1983; 105(2):136-144.
6. Gutekunst DJ, Liu L, Ju T, et al. Reliability of clinically relevant 3D foot bone angles from quantitative computed tomography. J Foot Ankle Res. 2013; 6(1):38.
7. Jenkyn TR, Nicol AC. A multi-segment kinematic model of the foot with a novel definition of forefoot motion for use in clinical gait analysis during walking. J Biomech. 2007; 40(14):3271-3278.
8. Wu G, Siegler S, Allard P, et al. ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion—part I: ankle, hip, and spine. J Biomech. 2002; 35(4):543-548.
9. Dayton P, Kauwe M, DiDomenico L, et al. Quantitative analysis of the degree of frontal rotation required to anatomically align the first metatarsal phalangeal joint during modified tarsal-metatarsal arthrodesis without capsular balancing. J Foot Ankle Surg. 2016; 55(2):220-225.
10. Pentikainen I, Ojala R, Ohtonen P, et al. Preoperative radiological factors correlated to long-term recurrence of hallux valgus following distal chevron osteotomy. Foot Ankle Int. 2014; 35(12):1262-1267.
11. Matthews M, Klein E, Youssef A, et al. Correlation of radiographic measurements with patient-centered outcomes in hallux valgus surgery. Foot Ankle Int. 2018; 1071100718790255.
12.  Barg A, Harmer JR, Presson AP, et al. Unfavorable outcomes following surgical treatment of hallux valgus deformity: a systematic literature review. J Bone Joint Surg. 2018; 100(18):1563-1573.
13. Shibuya N, Roukis TS, Jupiter DC. Mobility of the first ray in patients with or without hallux valgus deformity: systematic review and meta-analysis. J Foot Ankle Surg. 2017; 56(5):1070-1075.
14. Rush SM, Christensen JC, Johnson CH. Biomechanics of the first ray. Part II: metatarsus primus varus as a cause of hypermobility. A three-dimensional kinematic analysis in a cadaver model. J Foot Ankle Surg. 2000; 39(2):68-77.
15. Coughlin MJ, Jones CP, Viladot R, et al. Hallux valgus and first ray mobility: a cadaveric study. Foot Ankle Int. 2004; 25(8):537-544.
16. Kim JY, Park JS, Hwang SK, et al. Mobility changes of the first ray after hallux valgus surgery: clinical results after proximal metatarsal chevron osteotomy and distal soft tissue procedure. Foot Ankle Int. 2008; 29(5):468–72.
17. Faber FWM, Van Kampen PM, Bloembergen MW. Long-term results of the Hohmann and Lapidus procedure for the correction of hallux valgus: a prospective, randomised trial with eight-to 11-year follow-up involving 101 feet. Bone Joint J. 2013; 95(9):1222-1226.
18. Perera AM, Mason L, Stephens MM. The pathogenesis of hallux valgus. J Bone Joint Surg. 2011; 93(17):1650-1661.