Tarsal coalition.

PURPOSE OF REVIEW: Tarsal coalitions may cause painful pes planovalgus and recurrent sprains, and can lead to arthrosis if improperly managed. In this review, we discuss the current topics related to talocalcaneal and calcaneonavicular coalitions. RECENT FINDINGS: Tarsal coalitions are initially managed with conservative therapy, and when this approach fails, surgery is performed. Treatment of calcaneonavicular coalitions involves resection of the coalition and interposition of the extensor digitorum brevis muscle or fat, and in cases of marked valgus deformity, correction of the deformity. In talocalcaneal coalitions, recommendations include coalition resection for those affecting less than 50% of the area of the posterior facet and with a less than 16° valgus, coalition resection and valgus correction for those affecting less than 50% of the area and valgus greater than 16°, and isolated valgus correction for those affecting more than 50% of the area and with a more than or less than 16° valgus. Arthrodesis is reserved as a salvage procedure. SUMMARY: Talocalcaneal and calcaneonavicular coalitions can cause painful pes planovalgus. Their diagnoses are confirmed by plain radiograph, computed tomography, and, in cases of fibrous or cartilaginous coalitions, MRI. Initial treatment is conservative, and when symptoms persist, resection of the coalition is recommended along with tissue graft interposition with or without associated valgus correction. Arthrodesis is indicated as a salvage procedure whenever treatment fails or with advanced arthrosis.

Coalitions of the Tarsal Bones.

Tarsal coalitions are the result of impaired mesenchymal separation of the tarsal bones. The most common types include calcaneonavicular or talocalcaneal coalitions. Subtalar stiffness results in pathologic kinematics with increased risk of ankle sprains, planovalgus foot deformity, and progressive joint degeneration. Resection of the coalition yields good results. Tissue interposition may reduce the risk of reossification, and concomitant deformity should be addressed in the same surgical setting.

Subtalar Coalitions: Does the Morphology of the Subtalar Joint Involvement Influence Outcomes After Coalition Excision?

Posteromedial subtalar (PMST) coalitions are a recently described anatomic subtype of tarsal coalitions. We compared with clinical patient-based outcomes of patients with PMST and standard middle facet (MF) coalitions who had undergone surgical excision of their coalition. The included patients had undergone surgical excision of a subtalar tarsal coalition, preoperative computed tomography (CT), and patient-based outcomes measures after surgery (including the American Orthopaedic Foot and Ankle Society [AOFAS] scale and University of California, Los Angeles [UCLA], activity score). Blinded analysis of the preoperative CT scan findings determined the presence of a standard MF versus a PMST coalition. The perioperative factors and postoperative outcomes between the MF and PMST coalitions were compared. A total of 51 feet (36 patients) were included. The mean follow-up duration was 2.6 years after surgery. Of the 51 feet, 15 (29.4%) had a PMST coalition and 36 (70.6%) had an MF coalition. No difference was found in the UCLA activity score; however, the mean AOFAS scale score was higher for patients with PMST (95.7) than for those with MF (86.5; p = .018). Of the patients with a PMST, none had foot pain limiting their activities at the final clinical follow-up visit. However, in the group with an MF subtalar coalition, 10 (27.8%) had ongoing foot pain limiting activity at the final follow-up visit (p = .024). Compared with MF subtalar tarsal coalitions, patients with PMST coalitions showed significantly improved clinical outcomes after excision. Preoperative identification of the facet morphology can improve patient counseling and expectations after surgery.