This month’s fracture is a 4 year old gelding in jump race training which sustained a mid-body fracture on its left hind medial proximal sesamoid bone.
The proximal sesamoid bones are part of the suspensory apparatus acting as insertions for the suspensory ligaments at the back of the fetlock joint. Their integrity is critical to support of the lower limb and to joint function. Fractures in the middle two thirds of the bone generally disrupt entirely suspensory support on that side and thus require repair if the horse is to return to working soundness. The bones are irregularly pyramidal shaped and curved on all surfaces. They are in addition embedded within a large fibrocartilaginous pad which limits safe surgical access. Repair is technically challenging but combination of arthroscopy and intra-operative x-ray can produce a minimally invasive accurate repair and thus return to training.
Figure 1(a) is a dorsoplantar and (b) is a lateromedial radiograph illustrating the fracture (arrows) on arrival at the hospital.
Figure 2 is a 3-dimensional computed tomography (CT) image used to map the fracture and to determine the optimum site for screw placement.
Figure 3 are athroscopic views of the fracture: a) at initial examination; and b) following arthroscopically guided reduction (arrows = fracture).
Figure 4(a) is a dorsoplantar and (b) a lateromedial radiograph taken 2 weeks after surgery while the limb is still immobilised in a cast.
The horse was discharged from the hospital 3 weeks after surgery and is currently convalescing.