Computed tomography and fluoroscopy versus radiographic guidance for internal fixation of simulated dorsomedial-plantarolateral central tarsal bone fractures in nonracehorses.

OBJECTIVE

The aim of this study was to assess screw placement in simulated dorsomedial-plantarolateral central tarsal bone (CTB) fractures using two imaging guidance techniques - computed tomography (CT) with fluoroscopy compared to digital radiography alone (DR).

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Equine cadaver hindlimbs (n = 10 pairs).

METHODS

One tarsus per pair was randomly assigned to have a 4.5 mm cortical screw placed across the CTB using CT and fluoroscopy (CT/F group) or digital radiography alone (DR group). Postoperative CT was performed on all limbs. Variables related to marker placement, procedure time, and screw positioning were recorded and compared using a paired t-test for dependent means (p < .05).

RESULTS

Time for marker placement was longer for the CT/F group (p = .001), with no difference in total procedure time (p = .12). CT/F was not superior to radiography alone (p > .05) for parameters related to screw positioning. Based on the 95% CI, there was greater range in relative screw length using radiography (76.5%-91.2%) versus CT/F (78.4%-84.0%).

CONCLUSION

Internal fixation of CTB fractures can be successfully performed using either technique for imaging guidance. CT and fluoroscopy did not result in faster or more accurate screw placement compared to radiographs alone, except in determining screw length.

CLINICAL SIGNIFICANCE

Mild adjustments in fluoroscopic or radiographic angle appeared to be a point of variability in the perception of screw placement. While CT is recommended for improved understanding of fracture configuration and surgical planning, radiographic guidance may be a suitable alternative for internal fixation of dorsomedial-plantarolateral fractures.