Computed tomography identifies the proximodorsomedial subchondral bone of equine central tarsal bones as a predilection site for sclerosis, demineralisation and associated fractures

Abstract

Background: The distribution pattern of central tarsal bone (CTB) changes has not been described, except for slab- and dorsomedial–plantarolateral fractures. Objectives: To describe CTB changes in CT and document their distribution and associations. Study Design: Retrospective case series. Methods: Standing and recumbent tarsal CT studies from 94 clinical cases were retrospectively evaluated. General case information, degree of sclerosis (none-severe), lesions (demineralisation, cystoid, fissure/fracture) and their location were recorded, dividing CTBs into 8 regions. Results: Eighty five of 94 tarsi showed at least one region of moderate to severe sclerosis, of which 90% affected the dorsomedial region. The prevalence of lesions was significantly associated with higher degrees of sclerosis (p = 0.04) at this site. Of 32 demineralising lesions, 21 were in the proximal subchondral bone dorsomedially. Twenty-four CTBs showed fissures/fractures; 19/24 were in a dorsomedial–plantarolateral direction, and 17/19 were associated with demineralisation. Of five fissures/fractures with different configurations, none had associated demineralisation. There were 27 cyst-like lesions, 21/27 in the distal subchondral bone, of which almost half (13/27) located medially. Main Limitations: Retrospective design; heterogeneous, warmblood-oriented population; no clinical correlation of findings nor histological confirmation of described changes. Conclusions: Given the links between sclerosis, demineralisation and fissures/fractures, the dorsomedial proximal subchondral bone plate of the CTB must be scrutinised both in CT and radiography.