Current Concepts In Tarsal Coalition Surgery
Given the challenges of treating tarsal coalitions, these authors detail helpful clues in the physical exam and diagnostic imaging. They also provide step-by-step pearls for calcaneonavicular bar resection and talocalcaneal coalition resection, and review pertinent keys to postoperative management.
A tarsal coalition is a fibrous, cartilaginous or osseous union between two tarsal bones created due to failure of segmentation of primitive mesenchyme cells. In general, tarsal coalitions are relatively rare with a reported incidence of 1 to 5.6 percent in the general population.1-3
Calcaneonavicular (CN) and talocalcaneal (TC) coalitions occur most commonly. They respectively comprise 44 percent and 48 percent of tarsal coalitions. Talonavicular and calcaneocuboid coalitions are each present approximately 1 percent of the time with the remaining 6 percent of coalitions comprised of variations within the tarsal bones.1,4 Researchers have identified coalitions bilaterally in 50 to 60 percent of the general population.5,6
A tarsal coalition is a congenital abnormality that one may never identify unless it becomes symptomatic. Historically, the literature has described tarsal coalitions as becoming symptomatic in correlation with ossification dates and location.7
Calcaneonavicular coalitions often present in patients between 8 and 12 years of age with talocalcaneal coalitions becoming symptomatic later in the teenage years or 20s.5 Patients usually present with stiffness and an inability to accommodate uneven surfaces. The mechanical stress on the periosteum creates pain correlating with the children’s vague symptoms and their complaint of the inability to keep up with other children during physical activities.6
Researchers have attributed acute trauma to the area — consisting of a fall or sprain — to the creation of a painful coalition, especially within the adult population.5 The belief is that this occurs due to microfracturing and further remodeling at the coalition junction, which leads to degenerative changes. Free nerve endings within the periosteum and capsular structures surrounding the coalition become irritated and inflamed.3 There have been no documented cases of nerve endings within the coalition itself.5
In 2006, Nilsson and Coetzee described the presence of a stress fracture within a calcaneonavicular coalition in a marathon runner.8 We have also had patients present after sustaining a fracture at the coalition site, which resulted in symptoms requiring surgical excision of the coalition to provide long-term relief.
Key Diagnostic Pointers
Children and adolescents generally present with fatigue and globalized hindfoot pain. Parents often describe their children’s inability to perform certain physical activities or keep up with other children. Adults usually relate a history of subtle trauma with unresolving symptoms.
Tarsal coalitions may present as a component of severe pes planus deformity. However, they have also been documented in cavovarus feet.9,10 Peroneal and posterior tibial tendon spasms have occurred with these conditions.10 The literature has attributed talonavicular coalitions to clinodactyly, clubfoot and symphalangism.4 In 2007, Strauss, et al., discovered that 2 percent of 160 patients presenting with chronic lateral ankle instability also had concomitant coalitions.11
During the physical exam, the patient usually demonstrates stiffness within the tritarsal complex with limited frontal plane range of motion. The patient may present with additional medial column collapse, forefoot abduction or heel valgus. A double heel rise test can help determine the flexibility of hindfoot valgus. One can note this by the failure of the heel to resupinate as patients rise on their toes. Reconstitution of the longitudinal arch with dorsiflexion of the hallux is another test to evaluate for any fixed components of the deformity.