Review relevant bone anatomy of the hindfoot and midfoot. Become familiar withthe clinical presentation of a patient with tarsal coalition Learn the types of tarsal coalition. Review the appearances of tarsal coalitions on plain film, CT and MRI. Be aware ofhindfoot anatomic variants which may resemble non-osseous coalitions.

Tarsal coalitionis the congenital bridging of two or more tarsal bones Fig. 10 Fig. 11 and is often undetected and asymptomatic until late childhood. Itis a common condition which is often underdiagnosed afflicting approximately 1% of the population resulting in significant morbidity if left untreated. Most commonly patients present in childhood or adolescence probably reflecting the differential ossification rates of the tarsal bones. Symptoms include hindfoot pain or stiffness, pes planus and valgus deformity. Calcaneonavicular and talocalcaneal coalitions account for 90% of all tarsal coalitions...

The imaging features of tarsal coalition are varied. There are broadly three subtypes of coalition; fibrous, cartilaginous and osseous with progressive osseous changes occurring with increasing age.Tarsal coalitions are classified by the jointthat is involved and also the type of coalition. Non-osseouscoalitions(fibrous and cartilaginous)are subtle with abnormal, irregular joint space narrowing appearing degenerative on radiographs Fig. 1 . CT features are similar to that of osteoarthritis with joint space narrowing, sclerosis and subchondral cysts in an involved joint on a background of an otherwise normal...

The majority of tarsal coalitions involve the talus, calcaneum and navicular bones. Here we demonstrate multimodality imaging features a radiologist should look forin order to make a diagnosis based on their thorough understanding of hindfoot anatomy and anatomic variants in order to create an accurate report. This will enable prompt and appropriate patient treatment which in turn will limit morbidity and coalition progression.

Lawrence, D. A., Rolen, M. F., Haims, A. H., Zayour, Z., & Moukaddam, H. A. (2014). Tarsal Coalitions: Radiographic, CT, and MR Imaging Findings.HSS Journal ®,10(2), 153-166. doi:10.1007/s11420-013-9379-z Newman, J. S., & Newberg, A. H. (2000). Congenital Tarsal Coalition: Multimodality Evaluation with Emphasis on CT and MR Imaging.RadioGraphics,20(2), 321-332. doi:10.1148/radiographics.20.2.g00mc03321 Swensen, S. J., & Otsuka, N. Y. (2015). Tarsal Coalitions – Calcaneonavicular Coalitions.Foot and Ankle Clinics,20(4), 669-679. doi:10.1016/j.fcl.2015.08.001 Swensen, S. J., & Otsuka, N. Y. (2015). Tarsal Coalitions – Calcaneonavicular Coalitions.Foot and Ankle Clinics,20(4), 669-679....