Computed tomographic assessment of fracture characteristics and subchondral bone injury in Thoroughbred racehorses with lateral condylar fractures and their relationship to outcome

Abstract

To investigate the effects of fracture characteristics and concurrent subchondral bone pathology identified with computed tomography (CT) on the racing performance of Thoroughbred racehorses with fractures of the MC3/MT3 lateral condyle. Study design: Retrospective cohort study. Sample population: Thoroughbred racehorses (n = 50) with a fracture of the MC3/MT3 lateral condyle, which had preoperative CT and internal fixation performed.Methods: Medical records were reviewed for age, sex, limb, and surgical treatment. Computed tomography scans were evaluated to determine fracture characteristics including length, whether the fracture was incomplete or complete, and displacement. The presence of subchondral bone injury (SBI), sesamoid bone fracture, articular comminution, and fragmentation in the joint was noted. Racing data was obtained from an online database. Univariable and multivariable analyses determined associations between independent variables and outcomes. Results: Thirty-three (66%) horses raced after surgery. Horses with sesamoid bone fractures (P = .021), MC3/MT3 comminution (P = .016) and intraarticular fragmentation (P = .015) were less likely to race postoperatively. Concurrent SBI did not affect outcome. In the final multivariable model, sex (P = .015) and whether a fracture was incomplete or complete (P = .007) were the most significant predictors of racing postoperatively with females and horses with complete fractures being less likely to race. Conclusion:The prognosis for racing after a lateral condylar fracture is favorable but is decreased in horses with complete fractures and certain concurrent joint pathology. Clinical significance: Horses presenting with lateral condylar fractures commonly have concurrent joint pathology. Computed tomography can aid in

Identification of a previously unreported site of subchondral bone injury in the dorsodistolateral calcaneus in Thoroughbred racehorses

“…This suggests that identification of SBI of the DDLC is extremely difficult without cross‐sectional imaging and explains why this anatomic site of SBI has not been previously reported. Cross‐sectional imaging modalities, including CT, magnetic resonance imaging, and positron emission tomography, providing three‐dimensional detailed information have advanced the identification and understanding of SBI in the horse in the past decade 6,9,13,14 . Increased accessibility to cross‐sectional imaging in the horse, especially those that can be used on the standing animal, will likely continue to enhance our ability to detect early pathologic changes and make alterations in training programs of racehorses.…”

Comparison of Radiography and Computed Tomography for Evaluation of Third Carpal Bone Fractures in Horses

“…Bone loss and comminution at the proximal articular surface was under-recognised on DR compared to CT. Similarly, comminution of the articular surface was often unrecognized on radiography when compared to CT in horses with lateral condylar Fx of the distal metacarpus [23], another common injury in racehorses.…”

“…CT is extremely useful in the diagnosis of distal limb fractures in horses, and when other imaging techniques are inconclusive [7,8,[10][11][12][13] and can detect fractures, comminution, small osseous fragments (OF), periosteal new bone, osteoarthritis (OA), lucencies within the subchondral cortical plate and subchondral trabecular bone (collectively termed subchondral bone, SCB) or osseous cyst-like lesions (OCLL) at various sites not evident radiographically [7,8,12,[14][15][16][17][18][19][20][21][22]. Due to benefits over planar radiography, CT helps guide surgical approach in horses with a range of distal limb fractures [8,23] and determination of prognosis in horses with lateral condylar Fx [23]. The value of pre-operative CT in evaluation of carpal fractures has been reported; yet, only a limited number of horses with third carpal fracture were included [8].…”

Positron emission tomography assessment of metacarpal/metatarsal condylar fractures post surgical repair: Prospective study in 14 racehorses

“…However, in the current study horses with non‐PSG fractures all had focal uptake suggestive of stress remodeling, and potentially of POD, both at the fracture site and in a similar location in the contralateral fetlock (Figure 4). In a recent CT retrospective study of Thoroughbred racehorses with condylar fracture, 28/29 horses with signs of subchondral bone injury suggestive of POD in the lateral condyle on CT had fracture lines that extended through the lesion 19 . Previous studies have postulated that subchondral bone damage can be contained within the subchondral bone and lead to the formation of POD lesions or can cause fractures by extending into the trabecular bone 6 .…”

“…In a recent CT retrospective study of Thoroughbred racehorses with condylar fracture, 28/29 horses with signs of subchondral bone injury suggestive of POD in the lateral condyle on CT had fracture lines that extended through the lesion. 19 Previous studies have postulated that subchondral bone damage can be contained within the subchondral bone and lead to the formation of POD lesions or can cause fractures by extending into the trabecular bone. 6 These studies, in combination with the current study, suggest that condylar fractures can extend through the POD lesion or POD lesions might initiate the fracture.…”