Page 53 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

28 CHAPTER 1

VetBooks.ir 1.51 1.52

Fig. 1.51 Healing dorsal proximal cannon skin Fig. 1.52 Postoperative lateromedial radiograph of
pressure sores after the cast has been removed. The a proximal sesamoid bone mid-body fracture repaired
area was inadequately padded and the cast was not by a cerclage wire.
checked regularly enough.

by gentamicin-impregnated polymethylmethacrylate Screws and plating If fracture fragments are
(PMMA) placed in tubes as sidebars. An external skel- placed under compression, they can heal without
etal fixation device (ESFD) is a special external fixator callus formation. Precise anatomical reduction of the
consisting of 2–3 transfixation pins placed proximal to fracture for primary union is critical. Until recently, the
the fracture and linked by sidebars to a base plate that AO/ASIF system of lag technique fixation and dynamic
has been designed for use in adult horses with distal compression plates (DCPs) was the main implant com-
limb comminuted fractures. bination used to achieve this effect. More recently, the
development of the locking compression plate (LCP),
Internal fixation which allows for stronger and more versatile implant
Intramedullary implants combinations, has replaced the DCP in many proce-
• Steinmann pins. Infrequently used in the horse dures. The LCP allows the screw not only to engage
due to their lack of stability, but they can be used the bone but also to form a rigid fixation with the plate
in foals for medullary stack pinning of humeral itself, since the screw heads and plate holes are threaded,
fractures, certain olecranon fractures and leading to a more robust construct where direct contact
femoral capital physeal fractures. of the plate with the bone surface is not necessary.
• Interlocking nails. Recently designed for use in The DCP and lag screw systems use 4.5 and
foals for humeral and femoral fractures, but not 5.5 mm cortical screws and the LCP uses 5 mm
commonly available. locking screws but also allows for 4.5 and 5.5 mm
cortical screws to be used. Fractures can be repaired
Cerclage wire Used in certain situations such as tension with lag technique screw fixation (Figs. 1.53, 1.54).
band wiring of mid-body proximal sesamoid fractures Certain olecranon fractures can be repaired by using
(Fig. 1.52), rostral fractures of the lower and upper a caudally positioned narrow plate to act as a ten-
mandibles and certain olecranon fractures in foals. sion band (Fig. 1.55). Long-bone fractures such as