Tarsal Coalition Surgery And Flatfoot Repair: What You Need To Know

Given that current and emerging evidence supports the simultaneous correction of flatfoot and tarsal coalition resection, these authors discuss key considerations in single-stage repair with an eye on realigning the foot and preserving rearfoot mobility.

We now better understand the relationship between tarsal coalition and flatfoot as a combined pathologic problem. Historically, the surgical treatment of the tarsal coalition took center stage as surgeons focused on what material to place at the resection site and largely ignored the flatfoot altogether.

In 2008, the senior author published a three-part series that sparked the combined approach of fixing the flatfoot and removing the tarsal coalition during the same surgical setting.^1-3 Surgeons around the globe have also recognized the importance of realigning the foot in the face of a tarsal coalition.  

The logic for correcting the flatfoot with a talocalcaneal coalition is simple. If surgeons would repair a symptomatic flexible flatfoot without a coalition by realigning the foot, then the same logic should apply to the flatfoot with a tarsal coalition. After resecting the bony blockade of the coalition, doesn’t the foot then become flexible? Yes, of course it does. Granted, the resection does not ipso facto create a natural joint but rather a pseudo-joint, allowing the hindfoot complex to be mobile and return foot function.  

A well-known association exists between painful flatfoot and tarsal coalition. Consider that the true incidence of tarsal coalition is generally unknown because more patients with rectus feet are often asymptomatic and go undiagnosed in comparison to those with valgus feet. Varner and Michelson explored this in their review of tarsal coalitions in adult patients whose coalitions were not painful in adolescence but were only discovered in adulthood.⁴ Flatfoot deformity can be a normal physical exam finding with pediatric tarsal coalitions. However, in the adult cohort of the study by Varner and Michelson, only seven of 32 feet had a hindfoot valgus deformity and only one in 11 asymptomatic feet was in valgus. Secondary osseous pathology also develops as a result of tarsal coalition and pes planovalgus in the formation of a pseudo-articulation of the lateral heel and the distal fibula, a finding called calcaneofibular remodeling.²

Researchers have documented poorer results when one performs only a tarsal coalition resection in the face of significant hindfoot valgus.^5-7 Wilde and coworkers found poor outcomes with tarsal coalition resections in patients with hindfoot valgus greater than 16 degrees.⁵ Luhmann and Schoenecker found similar poor results in tarsal coalition resections in the setting of hindfoot valgus greater than 21 degrees.⁶

There are also reports of surgeons not addressing flatfoot at the index operation and performing subsequent flatfoot repair to correct the alignment, which resulted in improvement of symptoms. This again suggests the importance of correcting the flatfoot in the first place.⁷ Westberry and colleagues performed middle facet coalition resections for 12 tarsal coalitions, identified the untreated flatfoot as the source of continued pain and subsequently performed a lateral column lengthening.⁸ In 1987, Collins recommended orthotics after tarsal coalition resection, noting that otherwise foot pain may develop.⁹

In previous reports, some surgeons touched on the concept of treating tarsal coalition (talocalcaneal middle facet) and concomitant pes planovalgus deformity. In 1978, Cain performed medial closing wedge calcaneal osteotomies without resecting the tarsal coalition in an attempt to avoid rearfoot fusion.¹⁰ In 2003, Westberry performed radical sustentacular resections as an novel idea to remove the middle facet tarsal coalitions but also performed additional procedures to realign the foot in four of 12 cases.⁸ In 1988, 2001 and 2003, a few different surgeons used arthroereisis as an attempt to control the flatfoot along with coalition resections.^11-13

What The Literature Reveals About Single-Stage Surgery

In 2008, the senior author and colleagues were the first to report and popularize their experience performing middle facet tarsal coalition resection with concomitant flatfoot reconstruction as a single-staged procedure in bilateral feet.¹ Treating six feet in three patients with middle facet coalitions complicated by painful flatfeet, the authors performed coalition resection with a variety of flatfoot reconstructive procedures, and noted improvements in calcaneal pitch from a median 7.5 degrees to a postoperative median 14.5 degrees.

Since then, other researchers have reported similar success. Lisella and colleagues saw favorable outcomes on their series of eight feet in seven patients who had simultaneous tarsal coalition resection and flatfoot reconstruction.¹⁴ Quinn and coworkers reported on a retrospective comparison of calcaneonavicular coalition resections performed with concomitant flatfoot reconstruction in one group and without in the other group.¹⁵ Those who had flatfoot reconstructive procedures had superior postoperative radiographic measurements although researchers did not analyze the patients’ postoperative function. Mosca and colleagues reported on a series of patients who had successful treatment with Evans osteotomies in addition to tarsal coalition treatment.⁷

While the outcomes of these reports are generally favorable, like any surgery, single-stage tarsal coalition resection with flatfoot correction surgery does have its share of failures, especially considering the number of variable presentations and treatment options. In 2012, Hamel reported on eight feet that had talocalcaneal coalition resection with realignment calcaneal lengthening and gastrocnemius recession.¹⁶ He noted that one of the eight feet required fusion at 38 months. Hamel also reported his experience on 26 tarsal coalition resections with pes planovalgus correction, noting that two patients (approximately 8 percent) required subsequent fusion and four patients (approximately 15 percent) had ongoing discomfort.¹⁷

In the same study, the author also looked at the long-term effects of primary rearfoot fusion with tarsal coalition in 23 patients and 9 percent of those patients had ongoing tarsal symptoms.¹⁷ This suggests the failure rate of the two methods is similar. However, with primary fusion, there is no alternative next salvage surgery whereas those with ongoing discomfort after tarsal coalition resection with pes planovalgus correction have the option of rearfoot fusion to alleviate their symptoms.  

Kernbach and Blitz provided an algorithm for treating the tarsal coalition with concomitant flatfoot (see “A Guide To Treating Flatfoot And Talocalcaneal Coalitions” at right).¹ Based on the authors’ success in treating coalitions in flat feet, they propose that the degree of hindfoot valgus as well as the extent and the location of arthrosis guide procedure selection. Simply put, in the operative treatment of tarsal coalition, one should also address any existing flatfoot deformity. In some cases, this might mean fusing a severely flat foot. Additionally, as in the case with any arthritic joint, only an arthrodesis can salvage a tarsal coalition complicated by severe arthrosis.

Pertinent Surgical Pearls For Coalition Resection

Proper resection of the tarsal coalition is necessary before any flatfoot work can occur. It would seem that removing a tarsal coalition would be straightforward but it is not. Improper resection may lead to bony regrowth (recurrence), accelerated arthrosis formation and/or interference with flatfoot correction.

Removing the coalition. It is very important to perform a wide resection of the coalition. A narrow or incomplete resection is the most common reason for failure in the senior author’s revision tarsal coalition surgery cases. For both talocalcaneal and calcaneonavicular coalitions, we use the “pinky test,” which is nothing more than placing your pinky in the resection site as a guide for the approximate amount of space that should be present. A resection is not complete until the rearfoot complex has a return of motion.   

Resection of a tarsal coalition also has the propensity to damage its associated joints. While calcaneonavicular coalitions are classified as extra-articular, the resection invades the superolateral corner of the calcaneocuboid joint, one should take care to protect this articular cartilage. On the contrary, talocalcaneal coalitions are intra-articular and a resection that is too deep or improperly angled may damage the posterior facet articular cartilage of the subtalar joint. Talocalcaneal fibrous coalitions provide some surgical ease as the fibrous interval acts a pathway to the location of the posterior facet. However, osseous talocalcaneal coalitions require the surgeon to develop this plane altogether and the emphasis is on preserving the sustentaculum with performing a greater resection on the talar side.  

Interposition material. With nearly two decades of treating tarsal coalitions, the senior author finds the material for interposition to be less important but still a vital part of the procedure. Authors have reported on a variety of interpositional material, including bone wax, adipose tissue, flexor hallucis longus tendon and/or tensor fascia lata allograft.¹ Acellular material has been in use for coalitions and the senior author has also used similar materials off-label in some patients with favorable anecdotal results.¹⁸ Recently, surgeons have used the interposition of juvenile hyaline cartilage graft with good short-term outcomes in four feet (which also had concomitant flatfoot surgery by the way).¹⁹ The senior author’s preferred interposition material for talocalcaneal coalitions is a combination of bone wax, transferred local adipose and a segment of harvested aponeurosis and muscle.  

Four Rules For Flatfoot Repair With Tarsal Coalitions

There is not a single cookie cutter approach for the combined treatment of the flatfoot with tarsal coalition resections. No two cases are identical and it is important to develop a plan tailored for the patient in front of you. The decision tree usually involves the consideration of patient age, skeletal maturity, activity, the type of coalition, the presence of arthrosis and severity of the flatfoot deformity. Additionally, surgeons need to balance the incisional approaches for the coalition resection and the flatfoot surgeries. While every surgeon may have his or her own surgical playbook, below are four clinical pearls that the senior author uses when developing a surgical plan for single-stage coalition resection.²⁰

Rule #1: Avoid hindfoot fusions. Hindfoot fusion is an irreversible procedure. There is no going back. In the developing adolescent patient population, returning motion of the rearfoot has a theoretical benefit of continued morphologic improvement of the foot with time. Additionally, the absence of rearfoot motion places higher demand on the surrounding joints of the foot and ankle, predisposing joints to an earlier onset of arthritis.

In the setting of a Type III tarsal coalition, you may find rearfoot fusion to be unavoidable but you should tailor the fusion(s) to the specific joints that are arthritic. Do not mistake the talonavicular traction spurring with arthrosis. Additionally, the senior author has recognized the gray area in subtalar joint arthrosis assessment with tarsal coalition and also developed a computed tomography (CT) staging system to grade the posterior facet arthrosis with talocalcaneal arthritis.³ Stage I is normal to mild arthrosis with some sclerosis and lipping. Stage II is moderate arthrosis including joint space narrowing, osteophytes, cysts and erosions. Stage III is severe/end-stage arthritis with complete joint space loss, destruction of more than 50 percent of the posterior facet, osteophytosis and marked sclerosis. Stages I and II may be amenable to reconstruction whereas stage III requires fusion.  

Rule #2: Achieve radiographic improvement. The focus for flatfoot repair with tarsal coalitions is improvement. Depending on the severity of the flatfoot, it may be impossible to achieve radiographic perfection. This does not mean one should accept mediocrity but rather accept radiographic improvement over fusion in severe cases. There is a clear indication to perform a triple arthrodesis for severe flatfoot without a tarsal coalition. When there is severe flatfoot with a tarsal coalition, the same logic applies and a triple arthrodesis would indeed be indicated. However, long-term outcome studies are clearly needed in this particular scenario. Our experience in practice has demonstrated clinical improvements as long as the foot position is markedly improved.  

Rule #3: Perform a gastrocnemius intramuscular aponeurotic recession in most cases. The need for equinus correction in flatfoot is well established and it is no different with tarsal coalition patients. It is beneficial to avoid equinus correction at the Achilles level as the tendon gets bulbous and in some situations, Achilles lengthening is avoidable. However, one can manage most equinus in this population at the gastrocnemius level. A gastrocnemius intramuscular aponeurotic recession is the senior author’s preferred method.²¹ One can harvest adipose tissue for the interpositional material from the subcutaneous tissue as well.  

Rule #4: Calcaneal osteotomies are key. When surgeons use these procedures properly, medializing calcaneal osteotomies and Evans osteotomies are very powerful for patients with tarsal coalitions. If heel valgus is present, then a medial calcaneal osteotomy is indicated. A medial calcaneal osteotomy incision does not interfere with the talocalcaneal tarsal coalition resection incision but some incisional planning is necessary when using this with calcaneonavicular coalitions. Evans calcaneal osteotomies pair nicely with talocalcaneal coalitions and are effective at correcting the forefoot abduction. Special consideration is necessary if one is considering an Evans osteotomy with calcaneonavicular coalitions. All the surgical work occurs in the same vicinity and poses a risk of devascularization of the anterior calcaneus, leading to avascular necrosis or non-healing of the graft, although this is conjecture. Surgeons can consider double calcaneal osteotomies for appropriate patients.  

In Summary

We should no longer ignore flatfoot that presents with a tarsal coalition as there is enough evidence to support simultaneous correction, especially when the flatfoot is significant enough. Each tarsal coalition has its own set of challenges and one should tailor the method of flatfoot correction specifically for that patient. While rearfoot fusion may be a viable option to resolve the tarsal coalition and restore alignment, surgeons should consider preserving the rearfoot mobility in the absence of arthrosis in young patients.

Dr. Blitz is in private practice in Manhattan and is the creator of the Bunionplasty® procedure. He is board-certified by the American Board of Foot and Ankle Surgery, and is a Fellow of the American College of Foot and Ankle Surgeons. One can each Dr. Blitz at Info@DrNealBlitz.com .

Dr. Ciotola is the Chief Resident of Podiatric Medicine and Surgery at Lenox Hill Hospital in New York City.

References

1.     Kernbach KJ, Blitz NM, Rush SM. Bilateral single-stage middle facet talocalcaneal coalition resection combined with flatfoot reconstruction: a report of 3 cases and review of the literature. Investigations involving middle facet coalitions--part I. J Foot Ankle Surg. 2008;47(3):180-90.
2.     Kernbach KJ, Blitz NM. The presence of calcaneal fibular remodeling associated with middle facet talocalcaneal coalition: a retrospective CT review of 35 feet. Investigations involving middle facet coalitions—Part II. J Foot Ankle Surg. 2008; 47(4):288–94.
3.     Kernbach KJ, Barkan H, Blitz NM. A critical evaluation of subtalar joint arthrosis associated with middle facet talocalcaneal coalition in 21 surgically managed patients: a retrospective computed tomography review. Investigations involving middle facet coalitions-part III. Clin Podiatr Med Surg. 2010; 27(1):135-43.
4.     Varner KE, Michelson JD. Tarsal coalition in adults. Foot Ankle Int. 2000;21(8):669-672.
5.     Wilde PH, Torode IP, Dickens DR, Cole WG. Resection for symptomatic tarsal coalition. J Bone Joint Surg Br. 1994;76-B:797-801.
6.     Luhmann SJ, Schoenecker PL. Symptomatic talocalcaneal coalition resection: indications and results. J Pediatr Orthop. 1998;18(6):748-54.
7.     Mosca VS, Bevan WP. Talocalcaneal tarsal coalitions and the calcaneal lengthening osteotomy: the role of deformity correction. J Bone Joint Surg Am. 2012;94(17):1584-94.
8.     Westberry DE, Davids JR, Oros W. Surgical management of symptomatic talocalcaneal coalitions by resection of the sustentaculum tali. J Pediatr Orthop. 2003; 23(4):493–7.
9.     Collins B. Tarsal coalitions. A new surgical procedure. Clin Podiatr Med Surg. 1987;4(1):75-98.
10.     Cain TJ, Hyman S. Peroneal spastic flat foot. J Bone Joint Surg Br. 1978;60-B(4):527-529.
11.     Downey MS, DeWaters AM. Tarsal Coalition. In: Southerland JT, Boberg JS, Downey MS, Nakra A, Rabjohn LV (eds). McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery, Fourth Edition. Lippincott Williams & Wilkins, Philadelphia, 2013, pp. 598-635.
12.     Lepow GM, Richman HM. Talocalcaneal coalition: a unique treatment approach in case report. Podiatr Tracts. 1988; 1(1):38–43.
13.     Giannini S, Ceccarelli F, Vannini F, Baldi E. Operative treatment of flatfoot with talocalcaneal coalition. Clin Orthop Rel Res. 2003; 411:178–87.
14.     Lisella JM, Bellapianta JM, Manoli A 2nd. Tarsal coalition resection with pes planovalgus hindfoot reconstruction. J Surg Orthop Adv. 2011; 20(2):102-5.
15.     Quinn EA, Peterson KS, Hyer CF. Calcaneonavicular coalition resection with pes planovalgus reconstruction. J Foot Ankle Surg. 2016; 55(3):578-82.
16.     Hamel J. Results 3 to 6 years after resection of a talocalcaneal coalition combined with calcaneal lengthening osteotomy in children and adolescents. Fuß & Sprunggelenk. 2012; 10(3):175-83.
17.     Hamel J, Nell M, Rist C. Surgical treatment of talocalcaneal coalition: Experience with 80 cases of pediatric or adolescent patients. Orthopade. 2016; 45(12):1058-1065.
18.     Hounshell CR. Regenerative tissue matrix as an interpositional spacer following excision of a cuboid-navicular tarsal coalition: a case study. J Foot Ankle Surg. 2011;50(2):241-4.
19.     Tower DE, Wood RW, Vaardahl MD. Talocalcaneal joint middle facet coalition resection with interposition of a juvenile hyaline cartilage graft. J Foot Ankle Surg. 2015; 54(6):1178-82.
20.     Blitz NM. Preface: the surgical playbook. Clin Podiatr Med Surg. 2010;27(1):xvii-xviii.
21.     Blitz NM, Rush SM. The gastrocnemius intramuscular aponeurotic recession: a simplified method of gastrocnemius recession. J Foot Ankle Surg. 2007;46(2):133-138.